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Psychological Bulletin

1987,

Vol.

101. No. 2, 192-212

Copyright

1987

by the American Psychological

Association, Inc.

0033-2909/87/S00.75

The Nature of Phonological Processing and Its Causal Role in the

Acquisition of Reading Skills

Richard K.

Wagner

and Joseph K.

Torgesen

Florida State University

Three

bodies

of research that have developed in relative isolation center on each of three kinds

of phonological processing:

phonological awareness,

awareness of the sound structure of language;

phonological receding in lexical access, receding written symbols into a sound-based representa-

tional

system

to get from the

written word

to its

lexical referent;

and phonetic receding in working

memory, recoding

written symbols into a sound-based representational system to maintain them

efficiently in working memory. In this review we integrate these bodies of research and address the

interdependent issues of the nature of phonological abilities and their causal roles in the acquisition

of reading skills. Phonological ability seems to be general across tasks that purport to measure the

three kinds

of

phonological

processing, and

this generality apparently

is

independent

of

general cog-

nitive

ability. However, the generality of

phonological

ability is not complete, and there is an empiri-

cal

basis

for

distinguishing phonological awareness

and

phonetic recoding

in

working memory.

Our

review

supports a causal role for phonological awareness in learning to read, and suggests the possibil-

ity

of similar causal roles for phonological recoding in lexical access and phonetic recoding in work-

ing

memory. Most researchers

have

neglected

the

probable causal role

of

learning

to

read

in the

development of phonological skills. It is no longer enough to ask whether phonological skills play a

causal role in the acquisition of reading skills. The question now is which aspects of phonological

processing (e.g., awareness, recoding

in

lexical access, recoding

in

working memory)

are

causally

related to which aspects of reading (e.g., word recognition, word analysis, sentence comprehension),

at which point in their codevelopment, and what are the directions of these causal relations?

Phonological processing refers to the use of phonological in-

formation (i.e.,

the

sounds

of

one's language)

in

processing writ-

ten

and oral language. In this

article

we consider the nature of

phonological processing and its causal role in the acquisition of

reading skills through an integration of three bodies of research

on phonological processing that have developed

in

relative isola-

tion.

At the core of the first body of research is the development of

phonological

awareness, that

is,

one's awareness

of and

access

to the phonology of one's language (Mattingly, 1972).' Phono-

logical

awareness

is

demonstrated

by successful

performance

on tasks such as tapping out the number of sounds in a word,

reversing the order of sounds in a word, and putting together

sounds presented in isolation to form a word (Lewkowicz,

1980). To an

individual

with well-developed phonological

awareness, our alphabetic system—which conveys language at

the phonological

level—is

a

reasonable

approach to

visually

representing our spoken language. Conversely, an individual

lacking

such awareness

will find the

correspondence between

symbol and sound capricious at best (see, e.g., Liberman, Ru-

bin, Duques, & Carlisle, in press, for a recent presentation of

this argument).

The

helpful comments

of

Lynette Bradley, Peter Bryant,

Bob

Crowder, Virginia Mann, Keith Stanovich,

and an

anonymous reviewer

are

gratefully acknowledged.

Correspondence concerning this article should be addressed to Rich-

ard K.

Wagner, Department

of

Psychology, Florida State University, Tal-

lahassee, Florida 32306.

At

the core of the second body of research is phonological

recoding in lexical access, that is, getting from a written word

to its lexical

referent

by recoding the written symbols into a

sound-based representational system (Baron &

Strawson, 1976;

Coltheart,

Davelaar,

Jonasson,

&

Besner, 1977; Crowder, 1982;

Kleiman,

1975; Liberman &

Mann, 1981;Martin, 1978;

Meyer,

Schvaneveldt, & Ruddy, 1974). Tasks commonly used to assess

phonological recoding

for

lexical access involve deciding

whether

a string of letters represents a real word or a nonword,

and rapid naming of objects, colors, and other kinds of stimuli.

Whether getting

from the

written word

to its

lexical referent

necessarily

involves speech-related processes has been hotly de-

bated (see, e.g., Crowder, 1982; McCusker, Hillinger, & Bias,

1981,

for reviews of this literature). The consensus is that pho-

nological recoding is one of two basic means of lexical access,

the other being a more direct pairing up of the visual pattern

with

its lexical

referent.

Whereas lexical access that does not

involve phonological recoding appears to be available to skilled

readers for high-frequency words, phonological recoding ap-

pears to be an important means of lexical access in the early

stages of acquiring reading skills, and useful even to highly

skilled readers for less

familiar

words (Baron, 1979; Doctor &

Coltheart, 1980;Ehri&Wilce, 1979; Stanovich,

1982a, 1982b).

At the core of the third body of research is

phonetic

recoding

to maintain information in

working memory,

that is, recoding

1

What we call phonological awareness is also referred to as linguistic

awareness (Mattingly, 1980)

and

phonemic awareness (Lewkowicz,

1980;Rozin&Gleitman, 1977).

192



PHONOLOGICAL

PROCESSING AND READING

193

written symbols into a sound-based representational system

that enables them

to be

maintained efficiently

in

working mem-

ory during ongoing processing (Baddeley,

1982;

Conrad, 1964;

Mattingly, 1980), Recent evidence suggests that the role of a

speech-based, short-term store in normal reading comprehen-

sion may be less important than was originally thought, because

a surprising degree of comprehension occurs so soon after read-

ing a word that efficient storage processes are not required (see

Crowder,

1982,

for an

introduction

to

this literature). However,

efficient phonetic coding may play a vital role for beginning

readers. The task faced by the beginning reader is to: (a) decode

a series of visually presented letters, (b) store the sounds of the

letters

in a

temporary store,

and (c)

blend

the

contents

of the

temporary store to

form

words. Efficient phonetic coding for

storing the sounds of the letters enables the beginning reader

to devote the maximum amount of cognitive resources to the

difficult

task

of

blending

the

sounds

to form

words (Baddeley,

1979,1982;

Torgesen, Kistner, & Morgan, in press).

This article is not intended to be an exhaustive review of

three mature areas of research. For one thing, the length of such

a review

would

be

prohibitive.

For

another, adequate reviews

of

these separate literatures

are

available (see, e.g., Crowder, 1982;

Kleiman, 1975; Liberman et al., in press; Mann, 1985; Mc-

Cusker et al.,

1981).

Rather, our purpose is to provide a coher-

ent

account, spanning the three major areas of research, of pho-

nological

processing

as it

relates

specifically to the

acquisition

of

reading

skills. Further,

we focus on the

causal status

of

relations

between phonological abilities and the acquisition of reading

skills.

Careful evaluation of causal relations between phonological

processing and the acquisition of reading skills is especially im-

portant because the development of many cognitive skills and

the

acquisition of reading

usually

proceed hand in hand.

Thus,

it

is

difficult

to

distinguish

cognitive skills that

play

a causal role

in the acquisition of reading skill

from

those that are primarily

by-products of learning to

read. Ehri

(1979) has distinguished

four possible relations between phonological abilities and read-

ing. First, a particular phonological ability can be a

prerequisite

of

reading, without which the acquisition of reading skills is

severely limited. Second,

a

particular phonological ability

can

act as a

facilitator,

in which case children with the ability ac-

quire

reading skills

faster

than

those

without

it.

Third,

a

partic-

ular phonological ability can be a

consequence

of learning to

read, and thus a by-product rather than a cause of the acquisi-

tion of reading skills. Finally, a phonological ability

might

be a

correlate

of

reading ability, that

is,

related

to the

acquisition

of

reading

skill

only via their shared relation

with

some

third

variable, such as

IQ.

There are at least three major approaches to investigating the

causal status of relations between phonological processing and

the

acquisition

of reading

skills, each

of

which

has

limitations

when used alone. The first approach is to study individuals for

whom

the

usual hand-in-hand development

of

phonological

processes and reading does not occur (i.e., individuals for whom

the

acquisition

of

reading skills

is

particularly

difficult; see Sta-

novich,

1982a, 1982b; Wagner, 1986b,

for

reviews of this litera-

ture).

A

number

of

difficulties

are

associated with this ap-

proach.

For

example,

if

reading disabled students

or

adult illit-

erates

show

marked

deficiencies in

some aspect

of

phonological

processing, it is not easy to determine whether their

deficiency

in

phonological processing caused their reading

difficulties

or is

merely a by-product of their lack of reading skills. Most investi-

gations of the deficiencies of reading disabled children in pho-

nological processing do not inform us about causal relations

between phonological processing deficiencies

and

reading disa-

bilities. In this article we examine two other approaches to de-

termining causal relations between phonological processing

and the acquisition of reading skills: longitudinal correlational

studies and

experimental studies.

Longitudinal correlational studies involve obtaining mea-

sures of phonological processing and reading at several

points

in

time,

and

then testing alternative models

of

causal

relations

by the fit of the

models

to the

obtained

covariances

among mea-

sures (see, e.g., Kenny, 1979; Long, 1983a, 1983b,

for

introduc-

tions to

causal

modeling). Causal inferences can be drawn from

such

studies

to the

extent

one assumes

that

all

relevant variables

that might

be

causally related

to

both phonological

processing

and

reading

are

included

in the

model. This assumption relates

to the "third variable" problem: A correlation between two ob-

served

variables

may

derive

from

their relations

to an

unmeas-

ured third variable.

One can

never

be

sure about

the

extent

to

which this assumption

is

violated,

but in

practice,

the

longitudi-

nal correlational approach yields valuable information about

causal relations between phonological processing and reading.

Experimental studies are attempts to manipulate either pho-

nological or reading skills, usually by providing a training pro-

gram for the targeted skill. Whereas the experimental approach

offers more protection against the third variable problem than

the

longitudinal correlational approach,

the

problem

is not

eliminated. The

experimental approach assumes that one's

ma-

nipulation or training directly affects the targeted independent

variable and not another unobserved variable. Other limita-

tions are associated

with

using

training studies to experimen-

tally manipulate phonological processing abilities

and

reading

skill (see, e.g.,

Sternberg,

1983).

For

example,

it

could

be the

case that phonological awareness plays

a

causal role

in

learning

to

read

but

that phonological awareness cannot

be

trained,

at

least with the specific training program used. Conversely, train-

ing

effects can be

obtained

even

when

the

targeted ability

has

not been affected by training, especially when the training activ-

ities and the criterion share task characteristics (e.g., both are

based

on

speed, both

are

presented

on

microcomputers)

in ad-

dition

to

their both being measures

of the

targeted ability.

No approach by itself can definitively answer all the questions

about causal relations between phonological processing and the

acquisition of reading skill. Yet although each approach has its

limitations,

the

limitations

are to

some degree complementary

and

thus tend to cancel out when the approaches are combined

(Bradley & Bryant, 1985). This is why we are especially inter-

ested

in

results supported

by

both longitudinal correlational

and experimental methods.

This article

is

divided into

six

parts.

The first

part

is a

brief

introductory overview of the phonological nature of reading.

This sets the stage for the parts that

follow

by clarifying (a) the

definitions we have adopted, for purposes of the

present

discus-

sion, for the set of highly confusable terms that make it difficult

for interested observers to

follow

developments in the area of

phonological processing;

and (b) our

assumptions about

the



194

RICHARD K. WAGNER AND

JOSEPH

K. TORGESEN

level of

language conveyed

by the

printed word.

In the

second

through fourth parts, we consider relations between the acquisi-

tion of reading skills and phonological

awareness,

phonological

receding for lexical access, and phonetic receding to maintain

information in working memory, respectively. Each of these

three parts contains sections in which we examine longitudinal

correlational studies and experimental studies that focus on

causal relations between phonological processing

and

reading.

Because

the

literatures

we

review

are

mature, replete with stud-

ies that, on their face, support all possible

positions,

our exami-

nation of these studies is more fine-grained than is normal for

reviews of this sort. In several cases we have reanalyzed the orig-

inal

data.

In the fifth

part

of the

article,

we

explicitly consider

hypotheses about the nature of phonological processing that

emerge

from

examining interrelations among measures

of

different kinds of phonological processing. In the last part, we

summarize

the

major empirical

findings from our

review, iden-

tify

gaps

in

current knowledge

and

issues still

to be

resolved,

and propose how the gaps in current knowledge and unresolved

issues can be addressed in future research.

Overview: The Phonological Nature of Reading

2

We

begin this overview

by

summarizing

our use of the

easily

confused terms adopted

in

studies

of

phonological

processing,

and then

we

briefly discuss

the

level

of

language represented

by our alphabet and orthography. Our presentation, which is

intended to be modal rather than original, highlights conven-

tional thought

on the

phonological nature

of

reading. However,

many points are at issue about how language is represented in

writing, and we sidestep the hot debates only because they are

of secondary interest to our purpose.

Phones,

Phonemes,

and Phonetics

Exasperated readers

of the

phonological processing literature

who get lost in terminology are

justified

in exclaiming, "It's all

Greek

to

me " Many

of the

commonly used (and easily con-

fused)

terms derive from

the

Greek word phone, which trans-

lates into

"sound" or

"voice."

At its most basic level, speech consists of continuously vari-

able

waves

of acoustic energy. Spectrographic analysis of the

speech stream

has

shown,

for the

most part, none

of the

seg-

mentation we perceive when, for example, we hear three sounds

in

the

word "cat"

(Gleitman &

Rozin,

1977). The

apparent seg-

mentation of the speech stream is a cognitive/perceptual phe-

nomenon,

not a

characteristic

of the acoustic

stimulus

itself.

One step removed from the acoustic stimulus is the phonetic

level. Speech

is

represented

at the

phonetic level

by

phones,

which

are the

exhaustive

set of

speech sounds.

An

example

of a

phone is the

sound

of the

letter "t"

in the

word

"ten."

Letters

are associated with more than one phone. For example, the

sound of the letter "t" in the word "stop" is a

different

phone

than "t" in "ten." The relations between phones and the acous-

tic waves

from

which they are

perceived

are

complex

and not

well understood. A mapping occurs between parts of the speech

wave

and

individual phones

for

some types

of

phones (e.g., non-

diphthongized vowels, e.g., the sound of the "a" in "wave").

However, for other types of phones, what we perceive from a

part

of the

speech

wave

depends

on the

characteristics

of the

preceding and succeeding speech sounds (Gleitman & Rozin,

1977).

Although the sound of the letter "t" is different in the words

"ten"

and

"stop," such

differences are not

perceived

in

everyday

speech. The perceived sound distinctions are referred to

as

pho-

nemes. A phoneme consists of a group of phones that speakers

of a language consider to be variations on the same sound (Bal-

muth, 1982).

The

individual phones that make

up a

phoneme

are

referred

to as ollophones of that phoneme. For example, the

sounds of the letter "t" in the words

"ten," "stop," "matter,"

and

"bit"

are allophones of the

English consonant phoneme

/t/,

and the sounds

of

the letter "i"in the words "bite,"

"hide,"

and "tile" are

allophones

of the

English vowel phoneme

/ai/.

Midwestern spoken English can be represented by a total of 45

phonemes

(16

vowel phonemes

and 29

consonant phonemes;

Denes & Pinson, 1963).

Phonemes represent language

at the

phonological level.

Two

additional terms are commonly used in reference to this level

of language. The first,

morphophoneme,

aptly conveys the no-

tion that meaning (morpho) as well as sound (phoneme) is rep-

resented by our writing system and orthography. The second

term, used interchangeably with the first, is systematic

pho-

neme. This term derives

from

Chomsky and Halle's (1968)

analysis

of the

phonology

of

English.

On

their view,

our

knowl-

edge

about words is represented in our lexicons by abstract

strings

of

systematic phonemes. What

is

systematic

or

abstract

about this representation is that families of words that are re-

lated

by

meaning

(e.g.,

heal, health, healthy) share

one

lexical

entry:

/hel/. The spelling of the lexical entry

/hel/

is to some

degree informative about its sound. Speech involves using

pho-

nological rules (e.g.,

the vowel

shift rule responsible

for the

change

in

pronunciation

of the

second "e"

in the

word "extrem-

ity," compared to its pronunciation without the suffix in the

word

"extreme")

to

transform

the

abstract phonemes into sur-

face

phones that, in turn, relate to the

articulatory

gestures we

know

as

speech.

The syllable, which is the smallest independently articulable

segment of speech, is yet another unit of speech segmentation.

Vowels

are produced when the vocal tract is open and the vocal

folds

are

vibrating. Consonants

are

produced

by

constricting

the vocal

tract.

The

alternate opening

and

closing

of the

vocal

tract roughly corresponds

to a

syllable,

but it is

often

difficult to

determine

the

precise beginning

and end of a

syllable

(Balmuth,

1982).

It

bears repeating that there

is

considerable debate about

the

specific nature of phones, phonemes, and syllables. The some-

what simplistic picture

we

have presented

is

intended

to

make

it easier for the reader to

follow

the ensuing discussions. The

issues under debate

are by no

means trivial,

and

their resolution

will be consequential to our understanding of relations between

phonological processing

and

reading.

2

In this

overview

of the phonological

nature

of reading, we have re-

lied heavily

on Balmuth (1982),

Crowder

(1982), and

Gleitman

and

Rozin

(1977).

The interested reader is encouraged to consult these very

useful sources.



PHONOLOGICAL PROCESSING AND READING 195

Representing Spoken Language With Our

Alphabetic

Writing

System

There are two common fallacies about how language

is

repre-

sented by our alphabetic writing system and our English orthog-

raphy (the spelling conventions within our alphabetic writing

system). The first

fallacy

is the

commonsense

yet oversimplified

notion that writing is just the visual expression of language.

What is fallacious about

this

idea is that there is great variety

in the aspects of a language that a writing system might convey,

ranging

from levels close to the sound to levels close to the

meaning (Crowder, 1982). Writing might represent articulatory

gestures—with symbols corresponding to articulatory gestures,

such as pressing one's tongue to the roof of one's mouth. Alter-

natively, writing might represent concepts such as

"middle"

in

a logographic

fashion (e.g.,

the

symbols ": :")that conveys

no

information about pronunciation.

The second

fallacy

is

that

English is a phonetic orthography, in which letters represent

speech sounds. If English were

truly a phonetic

orthography,

the

pronunciation of the sequence of letters "heal" would be the

same for the words heal and healthy, and words such as sword

and knee would not exist at all

Most researchers believe that our writing system represents

language at the phonological level. When language is repre-

sented at the phonological level, writing is related to the sound

of

a word being represented but with compromises that some-

times

reflect a

word's meaning (Crowder,

1982).

Consider

the

previously mentioned example of heal and health. The letters

roughly correspond to the sounds of the words—one would not

pronounce either of the words as

banana,

for example—yet

their spelling provides no clue that the first parts of the words

are pronounced differently. Thus, the relation between the letter

group "heal" and its pronunciation is compromised because the

very

same letter group

is pronounced differently in the

words

heal and health, and this compromise reflects the words' shared

root meaning.

An alphabetic orthography such as

ours,

that represents lan-

guage

at the

phonological level,

is an

optimal system

of

repre-

sentation if we assume that lexical entries consist of strings of

systematic

phonemes. The optimal nature of our alphabetic or-

thography

refers to the notion that our writing system repre-

sents words in terms of the same units (systematic phonemes)

by which words are represented in our lexicon.

3

With this background,

we are

ready

to

consider

the

role

of

phonological awareness in learning to read. The beginning

reader really has two basic things to learn: Printed symbols rep-

resent units of speech, and the unit of speech represented is

the phoneme (Crowder, 1982). Learning that printed symbols

represent

units

of

speech

is

fairly trivial.

Even severely

disabled

readers can learn to read sentences in which words are repre-

sented

as Chinese ideographs (Rozin,

Poritzky,

&

Sotsky,

1971).

What is difficult is learning that printed symbols represent sys-

tematic phonemes, that is, becoming aware of the phonological

nature

of our language.

Phonological

Awareness and the Acquisition

of

Reading

Skill

Proponents of the view that phonological awareness is vital

to the acquisition of reading skill argue that an individual with

phonological

awareness

has a

number

of

advantages over

an in-

dividual without it in learning to read. First, an individual with

phonological awareness is likely to view our alphabetic orthog-

raphy as a sensible way of representing her language. Otherwise,

the patterns of

letter-sound correspondences will seem strange

and arbitrary (Mattingly, 1980). Second, it is argued that learn-

ing to read new words involves segmenting the letter string into

units that

correspond

to individual sounds (phonemes) and

blending

the

individual sounds together

to

pronounce

the

word.

The point of this argument is that an awareness of phonemes is

a prerequisite of the ability to segment letter strings into pho-

neme-based units and to blend the resulting phonemes into

words.

The acquisition of reading skill might also

affect

the subse-

quent development of phonological awareness. The argument is

that learning to read provides explicit knowledge of the phono-

logical structure of language that complements the largely tacit

knowledge acquired

from

experience

at

listening

and

speaking.

The

analogy

of

learning

a foreign

language

may

help clarify this

point. Learning a

foreign

language typically requires consider-

able

effort

at mastering grammatical rules that a native speaker

of the

language takes for granted. Individuals sometimes report

that learning

the

grammatical rules

of a foreign language

made

them aware of grammatical rules of their own language, rules

they

previously were not aware of yet that guided their speech

and

writing nevertheless.

Relations Between Phonological Awareness and Reading

Phonological awareness develops at about the age children are

taught to read. Liberman, Shankweiler, Fischer, and Carter

(1974) examined the ability of

4-, 5-,

and 6-year-olds to seg-

ment words by phonemes and syllables. None of the 4-year-olds

could segment by phoneme, but

half

could segment by syllable.

Only 17% of the 5-year-olds could segment by phoneme, and

again half could segment by syllable. By age 6, 70% could seg-

ment

by

phoneme

and 90% by

syllable. Similar results were

re-

ported by Calfee, Chapman, and Venezky (1972), who asked

5'/2-year-old children

(a)

whether

two

words sounded

the

same

at

the

end,

and (b) to provide a word that rhymes with a pre-

sented word. Even after

practice

trials with

corrective

feedback,

children responded at chance levels in saying whether two words

sounded the same at the end. The children were able to produce

a

rhyming word

39% of the

time,

an

average that resulted

from

a mix of some children doing very well at the task and some

doing very poorly, with

few

in between. Further, success at pro-

ducing words that rhymed was related to success at

early

reading.

Whether or not a young child demonstrates phonological

awareness may depend critically on the nature of the task used.

Fox and Routh (1975)

found

some evidence

that

phonological

awareness may occur earlier than the age at

which reading

is

taught. They had 3- to 6-year-olds listen to monosyllabic words,

and

asked the children to say "just a little bit" of the word. Even

3

Our orthography

cannot

be

truly optimal, because

it

contains

anomalies (e.g., sword) whose spellings are not informative

about

their

meanings.



196 RICHARD K.

WAGNER

AND JOSEPH K. TORGESEN

the 3-year-olds could segment at least some words into their be-

ginning

and remaining sounds, and by age 5, children could

segment first and remaining sounds for over half of the words.

Strong

relations have been reported between performance on

various measures

of

phonological awareness

and

reading skill.

In a large-scale investigation, Calfee, Lindamood, and Linda-

mood (1973) gave the Lindamood Auditory Conceptualization

Test

(Lindamood & Lindamood,

1971)

and the Wide Range

Achievement

Test

(1978) to 660 students

from

kindergarten

through Grade 12. The Lindamood Auditory

Conceptualiza-

tion Test uses

colored blocks to represent sound sequences in

wordlike units.

For

example,

the

unit

sas

could

be

represented

with

two

blocks

of one

color

and one

block

of

another color

by

placing

the

different-colored block between

the

pair

of

same-

colored

blocks. Multiple correlations between reading

and

spelling composite scores and the score on the

Auditory

Con-

ceptualization

Test

were .7 or

higher

at each grade level. How-

ever,

the magnitude of the multiple correlations may overesti-

mate

the true degree of relation between phonological aware-

ness and

reading because IQ

was not partialed

out.

Rosner and

Simon (1971)

did

control

for IQ in a

study

of

relations

between the ability to say a word without one of its

sounds and scores on the Stanford Achievement Test (1982).

Subjects

in this study were 284 students from kindergarten

through

the

sixth

grade. Partial correlations between their mea-

sure of phonological awareness and the achievement test scores

ranged from

. 1 to .7, with a

median

of .5. The only

nonsignifi-

cant partial correlation (.1) was obtained for the sixth-grade

sample. Similar relations

have

been found between reading

achievement

and a variety of measures of phonological aware-

ness (see, e.g., Fox &

Routh,

1975; Helfgott, 1976; Liberman,

1973; Zifcak, 1981).

Having observed that the development of phonological

awareness

coincides

roughly

with

learning to read, and that

measures of phonological awareness are related to measures of

reading ability, we need to consider the causal status of whatever

relations may exist between phonological awareness and read-

ing. Before examining

the

longitudinal correlational studies

and

the training studies that

have

been done, we briefly consider

three studies of individuals with atypical developmental

courses

that avoid

some of the previously mentioned limitations

associ-

ated with this approach.

Morais,

Gary,

Alegria,

and

Bertelson

(1979) examined the

causal status

of the

relation between phonological awareness

and the

acquisition

of

reading skill

by

studying individuals

who

had not received

training

in reading. Morais et al. presented

illiterate

Portuguese

adults

from

an

agricultural community

tasks such

as

saying

words and

nonwords

without one of

their

sounds

(e.g., burn-urn), adding sounds to words and nonwords

(ant-pant), reversing the order of sounds in words

(bat-tab),

and

reversing

the order of

syllables

in words

(packrat-ratpack).

Half of the illiterate subjects failed every test, whereas every

individual in a literate control group whose members learned

to read as adults passed at least one test. Percentages of correct

responses for illiterates on the deleting sounds task were 26%

for words and

19%

for nonwords, compared with 87% and 73%,

respectively, for the literate control subjects. Percentages of cor-

rect responses

for

illiterates

on the

adding sounds task were

46%

for

words

and

19%

for nonwords,

compared

with

91%

and

71%,

respectively, for the literate controls. Finally, the illiterates re-

versed

the

order

of

sounds

in

words correctly only

9% of the

time, but were able to reverse the order of syllables in words

48% of

the time.

These results

led

Morais

et al. to

conclude that

phonological awareness does

not

arise automatically without

learning

to

read

an

alphabetic orthography.

One limitation of Morais et al.'s study is a general limitation

of

all research on atypical subjects: The results may apply only

to the

atypical individuals

studied, in

this case, Portuguese illit-

erates. However, other investigators have recently replicated and

extended

this

finding to groups of adult poor readers. Liberman

et al. (in press) measured the phonological awareness of a group

of

adult poor readers who attended a community literacy class.

On a first-grade

level phonological awareness task that simply

required identifying initial, medial, and final sounds in words,

errors were made on over 40% of the items. Similar results have

been reported

by

Byrne

and

Ledez (1983)

and by

Marcel

(1980). However, there is an important difference between

Morais et al.'s study of Portuguese illiterates and these

other

studies in terms of causal implications. We might assume that

the Portuguese illiterates could not read because they were not

taught how,

and

thus conclude that deficiencies

in

phonological

awareness resulted from a lack of reading instruction rather

than from deficiencies

in

phonological abilities.

In

contrast,

the

reading problems of more typical adult poor readers may result

from deficiencies in phonological abilities, deficiencies in in-

struction, or some combination of the two.

A final example of research using atypical subjects to investi-

gate

causal relations between phonological awareness and the

acquisition of reading skill was reported by Bradley and Bryant

(1978). They compared the performance of an older group of

poor readers on measures of phonological awareness to a youn-

ger group of normal readers that matched the older group in

reading level. They assumed that

the

older poor readers should

have experienced at least as much reading instruction and prac-

tice

as the

younger normal readers,

if not

more. Thus,

any

defi-

ciencies in phonological awareness for the older disabled readers

could

not be due to a

lack

of

practice

at

reading. Two tasks were

used

to

measure phonological awareness.

The first

required sub-

jects

to

identify which

of

four words lacked

a

sound shared

by

the other three words (e.g., sun, sea, sock, rag). The older disa-

bled readers performed more poorly on

this

task than the youn-

ger normal readers.

The

second task

was to

provide

a

word that

rhymed with

a

target word. Again,

the

older disabled readers

performed more poorly than

the

younger normal readers. Brad-

ley

and Bryant concluded that one aspect of phonological

awareness—sensitivity to rhyme and alliteration—was a

possi-

ble

cause

of

reading difficulties.

Longitudinal Correlational Studies

The maximally informative longitudinal correlational study

of


and

reading would consist

of

mea-

surements,

on at

least three occasions,

of

reading skill, phono-

logical awareness, and IQ for a large group of children. Ideally,

the first

occasion should occur before

the

children

had

learned

to read (e.g., preschool or beginning kindergarten levels), in

which

case the reading measure should be a brief assessment to

document that the children were indeed nonreaders. The sec-



PHONOLOGICAL PROCESSING AND READING

197

ond occasion should occur at the very early stage of reading

acquisition (e.g., first-grade

level),

and the third at a later stage

of reading

acquisition (e.g., second-grade level).

Support for phonological awareness as a determinant of suc-

cess at early reading

would

be provided by finding that the pho-

nological awareness of prereaders predicted their subsequent

success at reading, provided adequate attention is given to other

factors, such

as

IQ, that might

be

responsible

for the

predictive

relation. Conversely, support for practice at reading as a deter-

minant of

phonological awareness would

be

provided

by finding

that success at early reading

predicted

subsequent performance

on

measures of phonological awareness, again provided ade-

quate attention is paid to plausible third causes. Models posit-

ing reciprocal causal relations,

or no

causal relations

whatso-

ever,

could also

be

examined.

We know of no study that has incorporated the complete de-

sign for a

longitudinal correlational study

of

relations between

phonological awareness and reading just outlined. However, a

number

of studies have incorporated parts of the design, and

we

consider them next.

Mann and Liberman (1984) conducted a longitudinal study

of phonological awareness, short-term memory,

and

reading

for

62

children.

We focus

here

on the

results relating phonological

awareness to reading. Phonological awareness was assessed in

May

of their kindergarten year with a syllable segmentation task

that required the children to tap out the number of syllables in

words

they listened to. Reading achievement was assessed 1

year later.

The obtained correlation between kindergarten syllable seg-

mentation and

reading achievement

1

year later (r = .40, p <

.01) is consistent with the view that phonological awareness is

causally

related

to

reading.

However,

there

are at

least

two

plau-

sible alternative accounts of the relation between phonological

awareness and the acquisition of reading

skills

to consider. The

first is

that

the

relation between syllable segmenting

and

later

reading

achievement

is

indirect, resulting

from

both variables

being related to IQ. This account is implausible because the

partial correlation, with IQ held constant, between syllable seg-

mentation

and later reading was identical to the simple correla-

tion of .40. The second alternative account is that the causal

relation

is reciprocal, that is, that learning to read

plays

a causal

role in subsequent phonological awareness, and vice versa. This

alternative explanation cannot be fully examined because pho-

nological awareness was not

assessed

again with first-grade

reading and because a measure of reading skill at the time the

phonological awareness measures were obtained is not available

as a covariate. The children

were, however,

screened with the

Woodcock Reading Mastery Test

(1973)

to eliminate blatantly

skilled readers (V. A. Mann, personal communication, Septem-

ber 20,

1985).

Mann (1984)

has

reported

a

second longitudinal study that

extends these results. In January of their kindergarten year, 44

children were

given

(a) a syllable awareness task that required

reversing the

order

of

syllables

in 2- and 3-syllable

words,

(b) a

phoneme awareness task that required reversing the order of

phonemes in a

2-phoneme

nonsense syllable, (c) an IQ test (Pea-

body Picture Vocabulary

Test,

1981),

and (d)

several other mea-

sures that

are not of

interest

to us here. One year later, the same

children, now first graders, were given the Word Recognition

and Word Attack subtests of the Woodcock Reading Mastery

Test, and teachers rated them as

being

good, average, or poor in

reading ability.

No

relation

was found

between

the

kindergarten

syllable re-

versal task and first-grade reading, which is surprising because

of the

relation between syllable segmentation

and

reading

re-

ported

in Mann and Liberman's

(1984)

study. However, the cor-

relation between kindergarten phoneme reversal

and first-grade

reading achievement

was

astonishingly high (r = .75, p <

.001).

The partial correlation we obtained holding IQ constant was

identical, .75.

Mann's (1984) and Mann and Liberman's (1984) studies are

both consistent with a causal role for phonological awareness in

the

subsequent acquisition

of

reading skills. However,

whether

this represents only half of the picture, that is, whether the

causal relation might be reciprocal, cannot be determined from

these studies.

In one of two recent large-scale longitudinal correlational

studies,

Bradley

and

Bryant (1985) examined relations between


and

reading

in a

3-year longitudinal

study. They also did a training study that we consider in the

next section.

The subjects in the longitudinal study were 368

nonreaders who ranged from 4 to 5 years old at the beginning

of the

study. (Bradley

&

Bryant excluded

20% of

their original

sample of 503 children because they had acquired at least some

reading skills, and 35 children dropped out over the course of

the

study.) Phonological awareness

was

measured with

a

sound

categorization task: Children listened to lists of three (for the

4-year-old sample)

or

four (for

the

5-year-old sample)

words—

all but one of which shared an initial, medial, or final

sound—

and then indicated

which

word was the odd one out. For exam-

ple, children would hear "cot," "hut," "man," and fit, and

identify man as the odd word.

At the beginning of the

study,

the children

were given

the

sound categorization task, a memory span task requiring them

to

repeat

the identical lists of words in order without identifying

the odd one out, the

English

Peabody Picture Vocabulary Test,

and miscellaneous other tests. Approximately 3 years

later,

the

children were given

(a) two

standardized achievement tests

of

reading, a

spelling

test, and, for discriminant validation, a

group-administered

mathematics test; (b) the sound categoriza-

tion test again; and (c) a short form of the Wechsler Intelligence

Scale for Children (Wechsler, 1974).

The correlations between performance on the sound catego-

rization task and

performance

on

achievement

tests 3 years later

were

.52 and .57 for the two

reading tests,

.48 for the

spelling

test,

and .33 for the math test. Holding constant the variables

of (a) age at

initial testing,

(b)

performance

on

each

IQ

measure,

and (c) memory for the word lists, sound categorization

uniquely

accounted

for

between

4 and 10% of the

variance

in

reading, 6-8% of the variance in spelling, and 1-4% of the vari-

ance in math scores. With the exception of the lower value of

the percentage of variance accounted for in math scores, the

contributions of the sound categorization score were significant

at the .001 level.

These results suggest that the phonological awareness of pre-

readers is at least one causal factor in their success in early read-

ing and spelling. Of course, most of the variance in early reading

and spelling in this study was due to

factors

other than phono-



198

RICHARD

K. WAGNER

AND

JOSEPH

K. TORGESEN

logical awareness (e.g., IQ, educational history), but it is impor-

tant to note that phonological awareness was responsible for

between 4 and

10%

of the variance in reading and spelling

achievement. With the large number of subjects, these results

are quite reliable. Further, several aspects of the procedures

used in the study suggest that the figure of 4-10% of variance

accounted for represents a conservative estimate of the true de-

gree of interrelation between sound categorization and reading.

First, Bradley

and

Bryant

determined

the

proportion

of

vari-

ance in achievement scores accounted for by sound categoriza-

tion with

a

stepwise multiple regression

of the

achievement test

scores on age, two IQ measures, and memory performance. In-

cluding

both IQ

measures

individually rather than one compos-

ite score representing both can rob some variance simply by

chance

that

rightfully

belongs

to the

last entered phonological

awareness variable. Second, the regressions were done sepa-

rately for each of two standardized tests of reading, and sepa-

rately for 4- and 5-year-old samples. Combining the reading

measures should

have

yielded a more

reliable

criterion

variable,

and

combining

the 4- and

5-year-old samples

may

have been

justified,

because dropping 20% of the original sample based on

their reading skill probably restricted the range of

both

inde-

pendent and dependent variables. Finally, the 368 children for

whom data

analysis was performed included 52 children who

had received some

form

of special training during the course of

the

study. Because training was given to children with the worst

sound categorization skills and had a positive

effect

on final

reading

performance, including

both trained and untrained

children in the same analysis likely reduced the obtained pre-

dictive relation between sound categorization

and

reading skill.

Two aspects of Bradley and Bryant's (1985) procedures merit

additional discussion.

First,

their sound categorization task

might be a better measure of working memory' than of

phono-

logical awareness. Recall that

the

task requires children

to

listen

to lists of three or four words and then indicate which is the odd

one

out.

As

Bradley

and

Bryant correctly state, this

is a

test

of

memory as well as of phonological awareness because the child

must remember the list of words in order to identify the odd

one. Memory load apparently was a consideration in designing

the task in that Bradley and Bryant (1985) decided to give lists

of three words to 4-year-olds because "four words seemed to tax

their memory

too much , . ." and to

give lists

of four

words

to

5-year-olds because "three words seemed rather easy for the five

year

olds, whereas four seemed, nicely, not too easy and not too

hard

for

them"

(p.

39).

Including the

memory span task

in

regressions

of

academic

achievement

on the sound categorization task is a creative at-

tempt by Bradley and Bryant to

tease

out a measure of phono-

logical awareness from the composite measures of phonological

awareness and memory that the sound categorization task rep-

resents. Their logic was that variance in achievement test per-

formance attributable to memory span should be captured in

the regression analysis by the memory span measure, and that

whatever remaining variance

is

captured

by the

sound

categori-

ration

task should

be due to

that part

of the

measure that

re-

flects phonological awareness rather than memory. Yet such a

strategy

can be called into question because the simple span

measure

may not be a

valid measure

of the

memory require-

ments of the sound categorization task, a task that requires si-

multaneous maintenance of a list of words in a short-term store

while performing the cognitive operations required for picking

out

the odd

one. Tasks that assess storage

and

processing opera-

tions simultaneously

can be

thought

of as

more complete mea-

sures of

working

memory than are simple span tasks (Baddeley,

in press). Whereas working memory tasks, which have process-

ing demands similar to those of the sound categorization task,

assess the ability to store items while engaging in complex pro-

cessing, span tasks assess only isolated storage components

of

the working memory system. Support for the idea that Bradley

and

Bryant's span measure

may not

assess

the

"right" kind

of

memory is provided by the fact that measures such as they used

are not strongly related to more complex working memory

tasks

(Daneman

& Carpenter, 1980).

Although

we have argued that Bradley and Bryant's sound

categorization task

may not be a

good measure

of

phonological

awareness

per se, it

just might

be the

right measure

to use

pro-

vided that

the

memory demand of

the

sound categorization task

is

similar

to

that experienced

by an

individual processing pho-

nological information

while

actually reading. In such a case,

the complex measure of sound categorization

might

be a more

useful

tool

for studying phonological awareness as it is used in

ecologically realistic situations than purer measures

of

either


or

memory alone. Just what

is

being

measured by the sound categorization task is an important

question for future research.

The second aspect of Bradley and Bryant's procedures to

consider

when interpreting their

findings is

that because they

do

not report relations between early reading achievement and

later sound

categorization,

their conclusion that phonological

awareness has a causal

role

in reading may be only half of the

story: They

did not

address

the

possibility that learning

to

read

has a causal role in subsequent phonological awareness.

Another large-scale longitudinal correlational study of re-

lations between phonological awareness and later

success

at

reading

and

spelling

has

been reported

by Lundberg,

Olofsson,

and

Wall

(1980).

This study

is

particularly interesting because

Lundberg et al. used a number of measures of phonological

awareness, including tasks to measure (a) segmenting and

blending

of

syllables

and

phonemes;

(b)

determining whether

a

target phoneme is in the initial, medial, or final position in a

spoken word; (c) reversing phonemes; and (d) rhyme. In addi-

tion, there were

two

versions

of the

blending

tasks,

one

that used

concrete materials, and another that did not. The concrete ma-

terials consisted

of

pegs used

to

represent either syllables

or

phonemes, depending on the task. Words were constructed by

putting individual pegs into a

pegboard.

The subjects

were 143

Swedish kindergarteners who differ

from

the kindergarteners in

most other studies because their average age was 7 years.

Formal

instruction in Sweden begins 2 years later than in many other

countries. Thus, subjects were considerably older, yet no more

schooled, than the usual kindergarten student.

Near

the end of

their kindergarten year,

the

children were

given

nine measures of the kinds

of

phonological processing just

mentioned,

a

screening measure

of

reading ability,

and

several

other measures not of direct interest. One year later, at the end

of

first

grade,

the

children were given

an IQ

test,

as

well

as

tests

of silent reading

and

spelling. Teacher ratings

of

achievement

also were obtained. Six months later, at the beginning of second




199

grade, the

children

were

again

given the IQ

test

and the

silent

reading test, but a new spelling test was given because of

prob-

lems with the original

test.

The

correlations between

the

kindergarten measures

of pho-

nological

awareness

and first-grade

reading achievement ranged

from

a low of. 13 (p < .05) for segmenting words into syllables

with concrete materials, to a high of.

5

5

(p

< .001) for phoneme

reversal,

with

a

median correlation

of .45

(p

< .001).

Phonologi-

cal

measures requiring analysis

of

phonemes were more

strongly predictive of reading skill than were those that required

analysis

of

syllables (median correlations were

.47 and

.24, re-

spectively,

with

a

test

of the difference

between these values

yielding p < .001).

These simple correlations address the issue

of relations between individual measures of phonological

awareness and later reading; results from path analyses carried

out by Lundberg et al. address the issue of the simultaneous

relations between the phonological measures taken all at once

and later reading achievement. Among the measures of

phono-

logical awareness, skill at reversing the order of phonemes (with

path coefficients

of .56 and .47 for first- and

second-grade read-

ing, respectively), and to a lesser degree, skill at producing

rhymes (with path

coefficients of.

19 and .14, respectively) were

reliable determinants of reading achievement. None of the

other phonological awareness measures made

a

unique contri-

bution to the prediction of reading achievement.

Lundberg et al.'s

data represent

a

uniquely important contri-

bution to our knowledge of empirical relations among mea-

sures of phonological awareness: To our knowledge, theirs is the

only study

in

which

a

large number

of

common measures

of

phonological awareness were given to a large sample of individ-

uals. We took advantage of these data by reanalyzing them to

answer three questions. First, what

is the

nature

of the

interre-

lations

among measures of phonological awareness? Second, are

the observed relations between kindergarten phonological

awareness and first-grade reading independent of general cogni-

tive

ability? Third, are the observed relations between kinder-

garten phonological awareness and first-grade reading indepen-

dent of

preexisting levels

of

reading skill?

Interrelations

among


tasks. The spe-

cific question

we

asked about

the

interrelations among mea-

sures

of phonological awareness is whether different kinds of

phonological awareness tasks (e.g., segmenting

vs.

blending, syl-

lable vs. phoneme) tap

different

latent phonological abilities or

whether the different kinds of tasks tap a single latent phonolog-

ical ability.

A

principal-component solution

for

Lundberg

et

al.'s data yielded two components with eigenvalues greater than

1.

The

proportions

of

total variance accounted

for by

these

principal components were .53 and .14. The proportion

of

com-

mon

variance accounted for by the first principal component

was .80. After varimax rotation,

the

loadings

of the

phonologi-

cal measures on the first principal component were substantial

(from .61 to .91, Mdn = .86) for all variables except segmenting

words into syllables with concrete materials

and

rhyme. These

two measures were

the

only substantial loadings

on the

second

principal

component, with values of .83 and .73. These results

suggest that much of the variance in common measures of pho-

nological awareness

can be

accounted for

by a

single latent abil-

ity. Confirmatory factor analyses carried out to determine (a)

whether segmenting

and

blending represented

different

latent

abilities, and (b) whether tasks involving syllables and tasks in-

volving phonemes represented

different

latent abilities were

also consistent with this view, in that neither distinction was

supported.

Stanovich, Cunningham, and Cramer (1984) provide further

support

for

this conclusion. They gave

10

phonological aware-

ness tasks to 49 kindergarteners whose average age was 6 years,

2 months. With the exception of three tasks for which ceiling

effects were obtained, the tasks were highly intercorrelated. The

mean correlation between the pairs of tasks was .62. A first prin-

cipal

factor

accounted

for

47.8%

of the

total variance

in the

variables. Correlations based

on 31 of the

children between

the

kindergarten measures of phonological awareness and reading

1 year later ranged from .09 to .60, with a median of .41. Seven

of the 10 correlations were significant at the .05 level. Holding

IQ constant did not change the results much at all. The partial

correlations ranged

from

.08 to .58, with a median of .35. How-

ever,

it was impossible to determine from the data presented

whether these relations were independent of preexisting differ-

ences

in

reading skill.

General cognitive ability.

The partial correlations holding IQ

constant between Lundberg et al.'s phonological awareness

measures and first-grade reading scores were of special interest:

With such a large sample, these

partial

correlations provide un-

usually stable estimates of the degree to which each measure of

phonological awareness determines later achievement in read-

ing, independent of general cognitive ability. The partial corre-

lations

we

calculated from these data ranged

from a low of .09

(p

> .05) for segmenting words into syllables with concrete ma-

terials, to a high of.

5

3

(p <

.001) for phoneme reversal, with a

median of .42 (p < .05). These results suggest that kindergarten

phonological awareness is quite strongly related to first-grade

reading, independent of

general

cognitive ability.

Effects

of

preexisting

levels

of

reading

skill.

The

partial

corre-

lations just presented provide relatively strong support for a

causal role

of


in the

acquisition

of

read-

ing skill. However,

it is

obvious that

at

least some

of

Lundberg

et al.'s sample had some reading proficiency before the study

began, because performance on the reading screening measure

given at the beginning of the study was related to first-grade

reading achievement.

(If

none

of the

children could read, there

would be no variance in this variable and thus it could not be

related to any other variable.) Thus the observed relations be-

tween

kindergarten phonological awareness and first-grade

reading might originate

from

preexisting differences

in

reading

skill. To answer this question, we calculated partial correlation

coefficients

between kindergarten phonological awareness mea-

sures and first-grade

reading,

with the score on the kindergarten

screening test of reading held constant. The results were strik-

ing. In contrast to the simple correlations reported earlier, the

median of which was .45 with all being significant, the partial

correlations with kindergarten reading held constant ranged

from

-.07

(ns) to

.21 (p<

.01),

with

a

median

of .06 (ns).

Only

two of the nine partial correlation coefficients were significant

at the .05 level. It appears that differences in original level of

reading proficiency could have been responsible for the ob-

served relations between kindergarten phonological awareness

and first-grade reading achievement, thus making ambiguous

the causal implications of these data.



200

RICHARD

K. WAGNER AND JOSEPH K.

TORGESEN

We turn now to a consideration of experimental studies be-

fore

summarizing all of the evidence relating phonological

awareness to the acquisition of reading skills.

Experimental Studies

Experimental studies, often in the form of training studies,

are a convergent approach to determining the causal status of

relations between phonological awareness

and

reading.

If train-

ing

in


can be

shown

to

improve success

in early reading, we can infer that phonological awareness plays

a causal role in the acquisition of reading skill. Conversely, if

training

in some aspect of reading can be shown to improve

phonological

awareness,

we can infer

that reading plays

a

causal

role in the development of phonological awareness. We now

consider studies that address the effects of manipulating phono-

logical awareness on subsequent reading, and of manipulating

reading instruction

on

phonological awareness.

Effects of


training on reading

skill.

One of the most extensive training studies reported to date was

carried

out by Bradley and Bryant

(1985)

in

conjunction

with

their longitudinal

correlational

study of

sound categorization.

The

subjects

in the

training study were

65

children selected

on

the basis

of

their poor performance

on the

sound categorization

task. The children ranged in age from 5 years, 5 months to 7

years,

4 months, with a mean age of 6 years, 1 month.

The

children were assigned

to one of four

groups

in

such

a

manner as to match the groups as closely as possible on the

variables of sound categorization ability, IQ, sex, and age. Chil-

dren assigned to a sound categorization group (n

=

13) received

40 training sessions of unspecified duration once per week over

a 2-year period. The training consisted of a variety of activities

designed to teach categorization of words based on sound. The

children

were

trained individually, and because each child was

permitted

to

progress

at his or her own

rate, some progressed

further through a sequence of training activities than others.

Children assigned to a concrete sound categorization group

(n = 13) received the same training as the first group, and in

addition, used plastic letters

for

concrete demonstrations

of

shared sounds

among

words.

The

children would,

for

example,

use the letters to spell a series of words that shared one or more

sounds by leaving in place the letter or letters that represented

a

shared sound

and

replacing only those letters unique

to

each

word. Children assigned

to a

conceptual categorization control

group

received

an

equivalent amount

of training

using

the

same

words presented to children in the experimental groups, but

they were

trained to categorize the words based on conceptual

category (e.g., animals, colors) rather than sound. Finally, chil-

dren assigned

to a

no-treatment control group («

=

13) received

no training at all.

The outcome measures for which training effects were ex-

pected

were

standardized tests

of

reading

and

spelling achieve-

ment.

Overall,

the

rank ordering

of the four

groups

on the

crite-

rion measures of achievement was (a) best performance for the

sound categorization group that got the letter training, (b) next

best performance for the sound categorization group

that

did

not

get the

letter training,

(c)

third best performance

for the

conceptual categorization control group, and (d) poorest per-

formance

for the

no-treatment control group.

Of particular interest are comparisons of the sound categori-

zation and concrete sound categorization groups with the con-

ceptual categorization group,

a

group that

is

just

the

right con-

trol group for this training program. As predicted, the groups

differed reliably on the reading and spelling tests but not on the

math

tests.

However, nominal advantages

of

the sound categori-

zation group over

the

conceptual categorization control group

of 4 months for both reading and spelling and 3 months for

mathematics were not reliable

(p >

.05). In contrast, the con-

crete sound categorization group—the group

that

used letters

for

concrete demonstrations—exceeded

the

conceptual catego-

rization control group

by

about

9

months

in

reading (p < .05),

about

17

months in spelling

(p <

.01), but by only 3 months in

mathematics (ns).

In sum, these results suggest that long-term sound categoriza-

tion training, in and of itself, does not result in greater achieve-

ment in reading or spelling. When supplemented with training

in the

sound-symbol

correspondences provided by the spelling

practice with plastic letters, marked gains are

obtained.

The un-

answered question is whether a group that only received spelling

practice with

plastic

letters and no sound categorization train-

ing per se would have shown

gains similar

to

that of

the

concrete

sound

categorization

training group.

Fox and

Routh

(1976) examined the

effects

of training chil-

dren to blend phonemes on a paired-associate reading analogue

task that required decoding "words" made up of letterlike sym-

bols. The subjects were

forty

4-year-olds, half of whom were

randomly

assigned to receive sound blending training. After

training, the children learned to associate spoken sounds with

letterlike symbols

in a

paired-associate learning procedure.

The

reading analogue criterion test

was a

paired-associate learning

task for two lists of "words" constructed from the letterlike

symbols. The items were repeatedly presented until either all

items were named correctly on two consecutive trials or a maxi-

mum

of 20 trials had been given.

No

main

effect of the

blending training

was

found. However,

when a median split was done by skill at segmenting words into

their constituent syllables

and

sounds,

a

reliable interaction

was

found

between sound blending training and segmenting skill.

Sound-blending training improved performance on the read-

ing-analogue task, but only for children who could segment

words into

sounds

{high segmenters). There was no effect of

blending training for children who were less able to segment

words

into

sounds (low segmenters).

This

result has been widely

cited in support of the view that both segmenting and blending

skills are prerequisites of successful acquisition of reading skill.

Although

this

view

has intuitive appeal, a close examination of

Fox and Routh's work suggests that it may be a

mistake

to con-

clude from their study that both segmenting and blending skills

are important to early reading. First, the interaction between

blending training and segmenting skill occurred for only one of

two

item lists used in the reading-analogue task. Second, it is

likely that

the interaction obtained is an artifact of floor effects.

Taking, for example, the number of trials to

criterion,

the

means were 9.3 and

17.2

for the trained and control groups for

the high segmenters. Thus for high segmenters, blending train-

ing reduced

the

number

of

trials required

for

perfect perfor-

mance on the reading-analogue task. The problem arises in the

performance of the low segmenters. The mean number of trials



PHONOLOGICAL

PROCESSING AND READING 201

to

criterion

for

both

the

trained

and

control groups

was

20.0,

with a standard deviation of 0,

which

represents the maximum

number of trials

given

before discontinuing the reading-ana-

logue task. Because the performance of both the trained and

control low-segmenter groups was at the floor for this variable,

and because there was an effect of training for the high segment-

ers, it is impossible

for

there not to be an interaction of blending

training and

segmenting

ability. For all we

know,

the floor

effect

for the low segmenters may conceal a main effect of blending

training.

One final problem in interpreting these results deserves men-

tion because Fox and Routh remedied it in a

follow-up

study.

This

problem is that segmenting ability was not manipulated

and may

have

been a proxy for some other difference between

the

groups that is related to reading, such as

IQ.

Fox and Routh

(1984)

solved this problem

by

directly manipulating segment-

ing skill in a study of relations between segmenting, blending,

and

reading.

The

subjects

in

this experiment were 41 kindergar-

teners, 31

of

whom could

not

segment syllables into phonemes,

and 10 of

whom served

as a

contrasting group

of

segmenters.

The

31

nonsegmenters

were

randomly assigned to one of

three conditions, within the constraint of keeping the ratios of

boys to girls proportional across groups. Members

of

a segment-

ing

training group were trained

to

segment initial sounds from

the remaining sounds of words. The training took place in ses-

sions

lasting up to

15

min, 4 or 5 days per week, for 5 weeks.

Members

of a

segmenting

and

blending training group received

the same segmenting training as the segmenting training group,

as

well

as practice at

blending

the first

sound with

the

remaining

sounds in monosyllabic triphonemic words, for example:

m. .

.an,

p. .

.at, and

r. . .

un. Members

of a

control group

received

no training. Measures to determine whether the train-

ing

worked included Fox and

Routh's

(1975) phonemic segmen-

tation

task

and the Roswell-Chall Auditory

Blending

Test

(1963). The transfer task for which the effects of training were

examined was the

paired-associate

reading analogue task with

letterlike forms used

in the 1976

study.

The results showed that the segmenting training group per-

formed no better than the control group on the reading ana-

logue

task, although there was evidence of training on Fox and

Routh's

segmenting test. Thus, improving segmenting skill does

not by itself appear to enhance learning words made up of let-

terlike

forms."

The segmenting and blending training group per-

formed better than the control group on the reading analogue

task,

the

Roswell-Chall blending test,

and Fox and

Routh's pho-

nemic

segmenting task.

In

fact, their

performance on the

read-

ing

analogue task

was not

reliably

different from

that

of the

con-

trast group of segmenters who scored highest on all measures.

Unfortunately, a blending training-only group was not included

in

this

study, thus

one

cannot

be

sure whether

the

improvement

for the segmenting and blending training group represented an

interaction

of

segmenting

and blending or a

simple

main effect

of blending training.

In sum, Fox and Routh's

(1975,

1976) studies demonstrate

that phonological awareness training results in improved per-

formance in a

reading analogue task. Whether such improve-

ment is evidence of an interaction of segmenting and blending

skill

or

simply

a main effect of blending skill is unknown be-

cause of the floor effects in the earlier study (Fox & Routh,

1976) and the

lack

of a

blending training-only group

in the

pres-

ent

study.

Treiman and Baron (1983) carried the investigation of pho-

nological awareness training a step further by asking whether

the

effects

of training are specific to the actual spelling-sound

correspondences taught, or are general because training makes

children aware of the basic

fact

that spelling-sound correspon-

dences exist.

In

the second, and more powerful, of two experi-

ments,

they used a within-subject design to study the effects of

training on 20 nonreading kindergarteners. Each subject prac-

ticed segmenting and blending the initial and remaining sounds

of one set of triphonemic spoken syllables (e.g., hem, lig,

hig,

hem). They also practiced another set of similar syllables by

merely repeating them. Next, the children learned to associate

the individual sound segments of the syllables

from

both sets

with letters. Finally, children learned to "read" entire syllables

in a paired-associates learning task. The syllables

were

of two

types. Related syllables were syllables presented in their entirety

in either

the

segmenting

and

blending

or

repetition training

conditions, whereas

unrelated

syllables were syllables made

from the same segments but that had not been practiced pre-

viously in their entirety.

Evidence

for an effect of phonological awareness training on

the reading analogue task was present in a small but reliable

interaction between type of practice (segmenting and blending

vs. repetition) and item type (related vs. unrelated). For sylla-

bles that received segmenting and blending training, an average

of 9.2 errors were made on related items and 10.6 errors on

unrelated items.

For

syllables

that

received repetition practice,

an average of 9.6 errors were made on related items and 8.9 on

the unrelated items. This means that children were more likely

to combine written syllable segments into syllables on the read-

ing analogue task if they had previously been trained to segment

and blend the same spoken syllables. This is not a

large

effect,

but it should be remembered that the training took place over

only

4 days. Though the lack of a main

effect

of phonological

awareness training suggests that its effectiveness was specific to

the individual syllables trained, the interaction between type of

practice and item relatedness declined over the 4 days of the

experiment, which suggests that

as skill in

phonemic analysis

and synthesis increased, the effects of training began to appear

for syllables that received repetition practice as well.

Effects of

reading

instruction on

phonological awareness.

Alegria, Pignot, and Morals (1982) compared segmentation

ability in two groups of 6-year-olds. Both groups had received

approximately 4 months of reading instruction;

however,

the

instruction given one group was based on a

"phonics"

method

and that given the other group was based on a "whole-word"

method. The segmentation tasks of interest were reversing the

order of syllables in disyllabic words or pronounceable non-

4

One unusual feature of the segmentation training,

based

on the ex-

amples

presented

by the

authors,

is

that

the units to be segmented did

not consistently reflect either the

constituent

syllables or phonemes of

the

words.

For example, subjects were taught to

segment

the monosyl-

labic,

triphonemic

word man into m ... an. Yet, he word floor was

segmented

into fl . . . oor, sandy was

segmented

into san . . . dy, and

nose

was

segmented

into n . . .

ose. This might

explain the

lack

of a

training effect on the

reading

analogue

task.



202

RICHARD K.

WAGNER

AND JOSEPH K. TORGESEN

words and reversing the order of phonemes in monosyllabic

po-

lyphonemic words or pronounceable nonwords.

Reliable

effects were

found for type of reading instruction—

the phonics group did better—and for type of reversal—revers-

ing syllables was easier than reversing sounds. These main

effects are not particulary informative because (a) the groups

were not randomly assigned to type of reading instruction but

rather were sampled from two schools that happened to differ

in method of reading instruction, and (b) others

have

shown

that segmenting words into syllables

is

easier than segmenting

words into phonemes (Liberman et al., 1974). What is informa-

tive is that there was a reliable interaction between type of read-

ing

instruction and type of reversal. On the syllable reversal

task, the phonics and whole-word groups were correct on 67.5%

and 73.5% of the items, respectively, a

difference

of only 6%. In

contrast, on the phoneme reversal task, the phonics and whole-

word

groups were correct

on

58.3%

and

15.4%

of the

items,

respectively,

a difference five times larger than that

found

for the

syllable reversal task. What remains to be determined is

whether members of the phonics group were better at real read-

ing than members of the whole-word group, and if so, whether

the difference in reading skill

resulted

from the

differences

in

phonological awareness between

the

groups

or

from some other

source.

In a

related experiment, Goldstein

(1976)

evaluated

the

effects

of

learning

to

read

on the


and

sequential memory of 23 nonreading 4-year-olds. The 11 chil-

dren in the experimental group were taught to read using Book

1 of Fuller's

(1974)

"Ball-Stick-Bird" reading system. Training

was provided daily in

10-min

sessions for 13 weeks. A feature

of this reading system is its emphasis on blending sounds to

make words. The 12 children in the control group were read to

from the same book but neither read themselves nor were

trained in sound blending procedures. Segmenting and blend-

ing skills

were

assessed

before

and after training, as was sequen-

tial memory

for

sets

of

pictorial items whose names were sim-

ilar in sound

(e.g.,

cat, hat, can, bag) or not (e.g., horse, spoon,

fish,

hand).

The

training program

had

reliable effects

for

sequential

memory performance but not for either segmenting or blend-

ing. Actually, the

pretest-posttest

gain of the experimental

group on segmenting and blending was about 20% greater than

that

of the

control group,

but

with

only 23

subjects, even this

large

difference

was not significant. It is interesting to note that

almost half

of the

variance

in

acquisition

of

reading skills

by

members

of the experimental group was accounted for by pre-

test measures of segmenting and blending skills independent of

general cognitive ability.

A

study recently

carried out in

China provides support

for

reading instruction as a determinant of phonological aware-

ness. Read, Ahang, Nie, and Ding (1984) compared the phono-

logical awareness of a group of readers who had been trained in

Chinese logographic characters with that of a group of readers

who had been trained in the alphabetic spelling system

pinyin.

A

logographic system is nonphonological because there is a sep-

arate symbol

for

each entire word represented

in the

logogra-

phy.

On a phonological awareness task that required the

addi-

tion and deletion of phonemes, the group of readers that had

been trained in the alphabetic system performed

well,

whereas

the group that had been trained in the logographic system

did

not.

Summary

Phonological awareness appears to develop at about the age

children are taught to read, although there is evidence that even

younger

children

have

rudimentary phonological awareness

(e.g.,

Fox &

Routh, 1975).

The

development

of

phonological

awareness for syllables precedes that for phonemes, and phono-

logical awareness tasks involving syllables appear to be easier

than comparable tasks involving phonemes in general. Based

on factor analyses of the commonly used measures of phonolog-

ical awareness (e.g., segmenting syllables and phonemes, blend-

ing

syllables

and

phonemes, counting syllables, reversing

the or-

der

of phonemes), it appears that they are measures of a single

construct or underlying ability, rather than of multiple and un-

related skills (Lundberg et

al.,

1980; Stanovich et

al.,

1984).

Performance on

measures

of


is re-

lated to performance on measures of reading achievement. Fur-

ther,

the results of the longitudinal correlational studies taken

together indicate that phonological awareness

and

reading

are

related independent of general cognitive ability. This conclusion

is

based on the partial and

semipartial

correlations we calcu-

lated

from

the reviewed studies between measures of phonologi-

cal awareness and later reading achievement with 1Q held con-

stant, summarized

in

Table

1. In

general, phonological aware-

ness tasks involving phonemes are more highly related to

subsequent reading skill than are those involving syllables.

The results in Table 1 from Mann (1984), Mann and Liber-

man (1984), and Bradley and Bryant (1985) support a causal

role for phonological awareness in the acquisition of reading

skills. However, these studies do not address the possible causal

role for learning to read in the development of phonological

awareness. To do so would

have

required obtaining measures of

both phonological awareness and reading at several points in

time. The

deficits

in

phonological awareness found

for

adult

il-

literates

and the effects on


found for the

phonics method of reading instruction suggest a causal role for

learning to read in the subsequent development of phonological

awareness.

The results of the training studies reviewed

were

mixed.

Some evidence

was

obtained

for effects of

phonological aware-

ness training on the acquisition of reading skill but there were

also some glaring null results,

as in the

case

of

Bradley

and

Bry-

ant's (1985) sound categorization training. Although Bradley

and

Bryant reported impressive gains

for

children

who

received

phonological awareness training in the form of concrete dem-

onstrations using plastic letters, these gains may simply reflect

the extensive practice these children received in

letter-sound

correspondences through the spelling activities that were part

of the

training.

We

consider potential reasons

for the

mixed

re-

sults of training studies in some detail in the General Discus-

sion.

Phonological Receding

in Lexical Access and the

Acquisition

of

Reading Skills

In

recent years a substantial body of research has converged

on

the conclusion that there are at least two common means of



PHONOLOGICAL

PROCESSING AND

READING

203

Table

1

Correlations Between Phonological Awareness and

Later

Reading

Achievement

With IQ Held

Constant

Study, phonological awareness

task

Coefficient

Bradley&Bryant(1985)

Sound

categorization with 4-year-old

sample:

Neal

reading

Schonell reading

Sound

categorization with

5-year-old

sample:

Neal reading

Schonell reading

Lundberg, Olofsson, &

Wall

(1980)

Blending:

Phonemes

Phonemes/concrete materials

Syllables

Syllables/concrete materials

Segmenting phonemes/concrete materials

Identification of phoneme position

Phoneme

reversal

Rhyme

production

Mann (1984)

Phoneme reversal

Syllable

reversal

Mann

Liberman

(1984)

Counting syllables

Stanovich,

Cunningham,

& Cramer

(1984)

Delete initial phoneme

Segment initial phoneme

Replace

initial

phoneme

Sound

categorization:

Initial phoneme

same

Initial

phoneme different

Same as initial phoneme different,

but with negative instructions

Final consonant same

Final consonant different

Identify

a rhyme

Supply a rhyme

.25***

.31***

.21

20

.42***

.47***

.21***

.29"*

.44"*

.43"*

.53***

.20"

.75"*

nf

40

.36*

.49"

08

.32*

.58"

.46*'

.33*

.39*

.22

.05

•With

the

exception

of data from

Bradley

and

Bryant (1985),

the re-

ported values are partial

coefficients.

It was not possible to calculate

partial coefficients from their

data,

so

these

values are

semipartial co-

efficients holding constant two IQ

test

scores, age, and

score

on a

mem-

ory

span task. Semipartial

coefficients

are lower bound

estimates

of the

values of the partial correlations.

b

Neither

simple

nor partial

correla-

tion

was reported,

though Mann (1984)

indicated that the

simple

corre-

lation was not significant.

*p<.05. **p<.01.

"*p<.001.

lexical

access (see

Crowder,

1982;

McCusker

et

al.,

1981,

for

reviews

of this literature). The first means of lexical access,

which

has

variously been referred

to as

phonological receding

(Coltheartetal., 1977;

McCusker

etal., 1981), speech receding

(Crowder, 1982; Kleiman, 1975; Martin, 1978),

and

phonemic

receding (Baron & Strawson,

1976;

Meyer et al., 1974), refers

to receding written symbols into some kind of sound-based rep-

resentation, and then using this sound-based representation to

access

the

lexicon.

The

second means

of

lexical

access,

which

has variously been referred to as

direct access,

unmediated ac-

cess, or

visually

mediated access, refers to pairing up written

symbols with their lexical referents without using a sound-

based representation system. Phonological receding is used to

a lesser or greater degree by all readers, depending on the

famil-

iarity of a particular word, but it appears to be especially impor-

tant in the early stages of the acquisition of reading skills

(Baron, 1979; Doctor

& Coltheart, 1980;

Ehri

&

Wilce, 1979;

Stanovich, 1982a, 1982b). Facility of phonological receding in

lexical

access as a

determinant

of

early reading success

has

been

suggested by a number of phenomena and observations. We

briefly mention two of them.

First, the reading task on which good and poor readers

differ

the most is naming speed for pseudowords

(Hogaboam

& Per-

fetti, 1978; Perferti & Hogaboam, 1975; see also Stanovich,

1982a, 1982b, 1985, for a review of this and related issues in

reading). Pseudowords (e.g., nke) share the phonology of our

written language,

but

they cannot have

a lexical

address

to

which they might be directly paired because they are not real

words. They also cannot be processed as a familiar, or unified,

configuration of letters, because they have not been encoun-

tered previously as words. In decoding pseudowords, children

must

access and

integrate multiple phonological codes,

so the

decoding speed for pseudowords is particularly sensitive to

difficulties in phonological coding of visual stimuli. The ex-

treme difficulties of poor readers in decoding pseudowords sug-

gest that at least some of their difficulties in word reading are

due

to problems in generating the phonological code required

to

access

the

lexicon.

A more direct observation that suggests the importance of

phonological recoding in lexical access is that dyslexic children

are slower at naming series of objects, colors, numbers, and let-

ters (Denckla

&

Rudel,

1976).

Naming tasks such

as

these

re-

quire lexical access, and there now is substantial support for the

view that the problem for dyslexics in naming tasks is due to

deficits in using phonological information for lexical access, as

opposed

to deficits of a visual-perceptual nature (see Stanovich,

1982a;

Vellutino,

1979,

for

reviews

of

this literature).

For

exam-

ple, the poorer performance of dyslexics compared to normal

readers

disappears

on visual processing tasks that do not in-

volve either phonological recoding or overt speech (Bouma &

Legein, 1980;

LegeinA

Bouma,

1981).

The literature on naming rate is complicated by the fact that

differences in rate between good and poor readers may depend

to

some extent

on the

structure

of the

naming task. Stanovich

(1985), for example, has pointed out that studies using discrete

trial

naming tasks report smaller differences between reading

groups than do those that require subjects to name items in a

continuous series. However, a recent report by

Lorsbach

and

Gray (1985) indicates that naming

rate

is reliably associated

with

reading skill on discrete

trial

tasks if comparison groups

are substantially different from one another in reading ability.

Before turning

to

studies that

address the

causal status

of re-

lations between phonological recoding in lexical access and the

acquisition of reading skills, we should note that it may be im-

possible

to

devise

a

task that measures recoding

in

lexical access

and

little

else,

especially

for young children. The ideal task

should measure the efficiency with which (a) the appropriate

phonological codes are retrieved from memory, and (b) the lexi-

con is searched for a string of phonological codes that matches

the search string of retrieved codes.

Consider several commonly used tasks to

assess

these aspects

of phonological processing. The rapid naming of letters would



204

RICHARD K. WAGNER

AND

JOSEPH K. TORGESEN

seem to involve retrieving phonological

codes,

but not using

them to make lexical access. In addition to being incomplete,

another

problem with this task is that it cannot be used with

young children who do not know the alphabet. Further, differ-

ential knowledge of letter-sound correspondences can inflate

correlations between the rapid naming of letters and later read-

ing skill even among groups of children who know the alphabet.

Switching from naming letters to naming objects should avoid

this limitation, although once again, phonological codes are not

used to make lexical access.

Naming real words seems

to

involve both retrieving phono-

logical codes and using them to make lexical access. However,

this

task cannot be used with

nonreaders,

and, in common with

letter naming tasks,

differential

mastery of letter-sound corre-

spondences may account for much of the variance in perfor-

mance

for young children. Another problem is that it is possible

to access the lexicon directly, especially for high-frequency

words, and thus not use phonological codes at all. Switching

to pseudowords avoids this limitation but introduces another

problem: Pseudowords cannot

have

a lexical address; thus it

seems that naming pseudowords cannot

be a

valid measure

of

using phonological codes to make lexical access.

Longitudinal Correlational Studies

Wolf (1984)

has

reported results from

a

longitudinal study

of

relations between a variety of naming measures and reading.

The subjects were

115

kindergarteners, 98 of whom were fol-

lowed through the end of second grade. The naming tasks,

which were administered at the end of the kindergarten year,

included (a)

four continuous naming tests

for

colors, letters,

numbers, and objects (hand, chair, dog, star, ball); (b) a continu-

ous

naming task for alternating digits and letters (e.g., 2 a 6 s 9

p); and (c) a

continuous naming task

for

alternating digits, let-

ters, and colors. Measures of oral reading, word recognition la-

tency,

and reading comprehension were administered at the end

of the kindergarten, first grade, and second grade school years.

The

correlations between

the

kindergarten naming measures

and the first-grade measures of reading ranged from -.35

(p <

.001) for naming objects to -.71

(p <

.001) for naming alter-

nate digits and letters. (The correlations are appropriately nega-

tive because

the

measure

of

naming proficiency

was the

amount

of time required to name a series of items.) In general, the mag-

nitude of the relations between the naming measures and later

reading

varied

as a

function

of (a) the

stimuli

to be

named,

with

letters and numbers being more related than objects; (b) grade

level;

and (c)

reading ability.

Perhaps

the

most important

of Wolf's

results

is

that naming

speed for objects reliably predicted later reading ability. This

result

is of

greater interest than

the

larger correlations found

between

naming speed

for

letters

and

later reading ability

be-

cause relations between letter naming speed and reading ability

may reflect other properties they have in common besides

re-

quiring phonological receding (e.g., knowledge of letter-sound

correspondences).

The

extent

to

which these results support

a causal

role

for

phonological receding in lexical access in the acquisition of

reading skills

is difficult to

determine from

the

data presented.

First, the reported correlations, though large, may be inflated

by the

relations

of both the naming tasks and the reading mea-

sures with

IQ.

Second, it is not clear that naming rate

differ-

ences

necessarily resulted from differences in the efficiency of

phonological receding.

For

example,

the

naming rate differ-

ences might

reflect

the differential use of direct lexical access,

or, because the tasks

were

presented in a continuous naming

format, the ability to sustain speeded performance. Third, the

substantial correlations between the kindergarten reading test

scores and the naming measures indicate that a nontrivial pro-

portion of the kindergarten sample possessed some reading

skills when the naming tasks were first administered, and thus,

the

observed

differences in

naming speed might

have

been

caused by differential prior practice at reading. Finally, the

naming tasks apparently were not administered again after the

kindergarten year, making it impossible to test alternative

causal models that might resolve the ambiguity about the direc-

tion of

causality.

Lesgold and Resnick (1982) reported a 3-year longitudinal

study

of causal relations between word naming speed and read-

ing

comprehension that is at least indirectly related to the ques-

tion

of

causal relations between phonological

receding

and

reading. Their subjects

were

127 first graders, 46 of whom re-

mained as third graders at the end of study. Word naming speed

was measured

on

four occasions over

the

course

of the

study,

and measures of reading comprehension were obtained on

three occasions. Whereas word naming speed was related to

subsequent comprehension (with

one

exception), comprehen-

sion was not

related

to subsequent word naming

speed.

Lesgold

and Resnick concluded that speed or

automaticity

of word

naming

is

causally related

to the

ability

to

extract meaning

from

a text and is not simply the result of more

efficient

language

comprehension processes.

A

strength of this study compared to other longitudinal stud-

ies of relations between phonological processing and reading is

that the phonological measure (e.g.,

word

naming speed) was

given on multiple occasions over the course of the study, thus

permitting Lesgold and Resnick to test alternative models of

causal relations among the variables in their study. However, the

results of this study are

only

indirectly linked to the question of


receding

for lexical ac-

cess

and

reading.

Unlike naming

speed

for objects or

colors,

word

naming speed is obviously a composite measure that in-

cludes important reading

processes

other than phonological re-

coding.

Summary

The importance to reading of phonological

receding

in

lexi-

cal

access is supported by the magnitude of the

differences

be-

tween good and poor readers on naming speed for pseudowords

and the

naming

speed differences

between dyslexics

and

normal

readers

for

objects, colors, numbers, and letters. Markedly fewer

studies have

addressed

the specific question of causal

relations

between phonological receding in lexical access and the acquisi-

tion of reading skills than for phonological awareness. As a re-

sult, there is little evidence of causal relations.




205

Phonetic

Receding to Maintain

Information

in Working

Memory

A

number of models of

working

memory

have

been pro-

posed, each of

which

conceptualizes working memory as a stor-

age system of limited capacity that supports ongoing cognitive

processing

(Torgesen, Kistner, &

Morgan,

in

press). Baddeley

and his associates (Baddeley, 1981; Baddeley & Hitch, 1974;

Baddeley & Lieberman, 1980)

have

developed a model of work-

ing memory that has been applied to the problem of under-

standing

beginning reading (Baddeley, 1979, 1982; Mann &

Liberman, 1984). We briefly describe this model of working

memory and the possible role of phonetic receding in the acqui-

sition of reading skills

before

beginning our review of work in

this area.

Working memory

is conceptualized as a collection of

interre-

lated

subsystems, three

of

which

have

been identified

at

least

tentatively.

The

central

executive is a limited capacity work-

space that can be used to operate control processes (e.g., execu-

tive

routines

and

decision making)

or to

briefly

store

informa-

tion. The two other subsystems are "slave" systems to the cen-

tral executive in that information is sent to them for storage

at

the

discretion

of the

central executive. Which slave system

information

is

sent

to for

storage depends

on the

kind

of

infor-

mation to be

stored. Visual

or

spatial information

can be

sent

to a visuospatial scratch pad for storage. Verbal information can

be sent to a phonological store for storage, a process that in the

context

of reading is carried out by an articulatory

loop.

The phonological store and the articulatory loop are of pri-

mary

interest to us here. According to the working memory

model, verbal information is recoded phonetically and stored

in

working

memory

in

terms

of its

phonological features.

The

means by

which

verbal information

is

registered

in the

phono-

logical store depends

on

whether

the

information

is

heard

or

read.

Verbal

information that is heard is automatically regis-

tered in the phonological store. Verbal information that is read

also may be registered in the phonological store, through an

articulatory

loop activated when the reader

subvocally

articu-

lates the information (Baddeley, 1982).

A

number

of

studies

have

demonstrated

the

important role

of

phonetic coding

in

working memory tasks.

For

example, Katz,

Shankweiler, and

Liberman (1981)

had

good

and

poor second-

grade readers recall series of pictures that were either readily

labeled common objects

or

abstract line drawings

for

which ver-

bal labels were not apparent. Differences between good and

poor

readers

were

found

for

recall

of

objects that could

be la-

beled

but not for

recall

of the

abstract line drawings. Katz

et

al.

concluded

that the problem for poor readers is not a general

problem in working memory but a problem

specific

to coding

items phonetically.

Shankweiler,

Liberman, Mark, Fowler, and

Fischer (1979)

found that letter-span performance

of

skilled

readers

was

impaired when

the

names

of the

letters were

phono-

logically

confusable (e.g.,

b, c, d, p)

compared

to

their span per-

formance for nonconfusable letters, but less impairment was

found for less skilled readers. This suggests that good readers

make more

use of phonological

information

in

span tasks than

do poor readers (see

also,

Bisanz, Das, & Mancini, in

press;

Brady,

Shankweiler, &

Mann, 1983; Byrne

&

Shea, 1979;

Mann, Liberman, & Shankweiler, 1980; Perfetti & Lesgold,

1977, 1979; Perfetti &McCutchen,

1982;Swanson,

1978).

We next consider studies that

address

the issue of causal re-

lations between phonetic receding in working memory and the

acquisition of reading skill.

Longitudinal

Correlational

Studies

Mann and Liberman (1984) examined relations between

kindergarteners' memory span for word lists and first-grade

reading. Their subjects were

62

children who,

in May of

their

kindergarten

year,

were asked to repeat word strings that were

either phonemically

confusable

or nonconfusable. One year

later they were given the Word Recognition and Word Attack

subtests of the Woodcock Reading Mastery Test. If efficiency of

phonetic

coding in working memory is related causally to the

acquisition of reading skills, one would expect reliable corre-

lations between

the

performance

on the

kindergarten measure

of memory for word lists and reading skill 1 year later.

The

simple correlations between

first-grade

reading

and

kin-

dergarten word string span measures were .39

(p < .01)

for non-

confusable word strings and .26 (p > .05) for confusable word

strings. Partial correlations with IQ held constant are identical

to the simple correlations because IQ was unrelated to the crite-

rion measure of reading.

In

a follow-up study of 44 children, Mann (1984) replicated

these results. The correlation between kindergarten memory for

lists of nonconfusable word strings and first-grade reading ob-

tained in this study was .56

(p

< .001). Holding IQ constant, a

partial correlation of .55 (p < .001) is obtained.

These results, then, are at least consistent with the

view

that

efficiency

of

phonetic coding

in

working memory

is

causally

re-

lated to the acquisition of reading skills, although a stronger

case

could be made had a measure of reading skill at the time

the phonological measures were obtained been available as a

covariate. We turn now to experimental studies that

have

inves-

tigated causal relations between phonetic receding

in

working

memory and the acquisition of reading skills.

Experimental Studies

Alegria

et al., (1982), using two groups of 6-year-olds, com-

pared memory span performance for drawings of objects with

either phonologically confusable or nonconfusable names. One

group had received 4 months of reading instruction using a

phonics method, the other received 4 months of reading in-

struction using a whole-word method. Although the groups

differed

in their ability to segment sounds, there were no group

differences in memory span performance. This result is not

consistent

with the view that instruction in reading emphasiz-

ing the phonological features of words leads to greater efficiency

of

phonetic receding in working memory. We do not want to

make

too much of this null result, however, because it is based

on groups of only moderate size (32 children in each of two

groups) that were preexisting rather than created by random

assignment to method of reading instruction.

In

addition to examining the

effects

of reading instruction on

working

memory performance, we can also examine the effects

of training designed to improve memory span performance on



206

RICHARD K.

WAGNER

AND

JOSEPH K.

TORGESEN

subsequent reading skill. The problem here, of course, is that

performance on span tasks is affected by several different kinds

of processing operations (Dempster, 1981). Large improve-

ments in

span performance

can be

obtained

by

teaching

special

mnemonic strategies like cumulative rehearsal (see, e.g., Butter-

field,

Wamgold,

&

Belmont, 1973)

or

temporal chunking (see,

e.g., Torgesen & Houck,

1980).

Furthermore, there is substan-

tial evidence that children with reading problems perform

poorly on many memory tasks because they do not use appro-

priate strategies efficiently (Bauer, 1977, 1979; Shepherd,

Gel-

heizer, Solar, 1985; Torgesen, 1977).

Even though memory span performance might

be

improved

by teaching mnemonic strategies, there is little reason to expect

such training

to affect

reading performance.

It is

doubtful that

elaborate strategies for improving simple storage of items on

span tasks can be used effectively while performing complex

tasks like reading (Torgesen,

Kistner,

& Morgan, in press).

Reading

occurs at a rate that probably precludes the use of elab-

orate strategies to store individual letters, words, or phrases dur-

ing

processing. Further, the use of elaborate mnemonic strate-

gies may tie up cognitive resources that could be more usefully

applied to other important

processes

in reading.

Summary

One important rationale for expecting efficiency of phonetic

coding in

working

memory to be related to the early acquisition

of reading skills is that efficient phonetic coding should enable

the

reader to apply maximum resources to the difficult task of

blending

together isolated phonemes to make words.

There is considerable evidence that good and poor readers

differ on

memory span tasks

and

that these differences derive

primarily

from differences in the efficiency of phonetic recod-

ing

in

working memory. Further,

the

relation between

efficiency

of phonetic

receding in

working memory

and

reading skill

is

independent of general intellectual ability.

Results

of the longitudinal correlational studies that have ad-

dressed

the issue

suggest

a

causal role

for efficiency of

phonetic

coding in

working

memory in the acquisition of reading skills.

As was true for research on phonological awareness and phono-

logical receding in

lexical access,

insufficient

attention

has

been

paid

to a

possible causal role

for

learning

to

read

in the

develop-

ment

of

phonetic coding

in

working memory.

Relations Among

Phonological

Awareness, Phonological

Receding

in Lexical Access, and Phonetic Receding

in Working

Memory

We have reviewed three literatures that have developed in rel-

ative

isolation. Each literature

has its own set of

tasks,

and for

the most part, its own set of researchers. With few exceptions

(e.g.,

Blachman, 1984; Crowder, 1982;

Liberman & Shank-

weiler, in

press; Mann,

1985), the

focus

has

been

on

relations

between

one of the

three kinds

of

phonological processing—

usually operationalized by a

single task—and reading.

The

question we

address here

is

whether

the

tasks commonly used

to measure phonological awareness, phonological receding in

lexical access, and phonetic receding in working memory repre-

sent

substantively distinct kinds

of


or

skill.

We

briefly

consider the theoretical and practical signifi-

cance of this question.

Theoretical Implications

The theoretical importance of the question concerns how

many latent phonological abilities or kinds of processing there

are. It is

possible that

the phonological tasks commonly used to

measure

awareness,

receding

in

lexical access,

and

receding

in

working memory

are

basically measures

of one

general latent

ability. Alternatively, it is also possible that phonological aware-

ness and the actual use of phonological information—either in

lexical access

or in

working memory—represent separate latent

abilities. Finally, awareness,

use in

lexical access,

and use in

working memory might represent separate latent abilities or

kinds

of phonological processing.

The ambiguity about the nature of latent phonological abili-

ties carries over into interpreting performance on any given

phonological task. For example, two measures of phonological

awareness that reliably predict the acquisition of reading skills

are phoneme reversal and Bradley and Bryant's (1985) sound

categorization

task. Compared to other commonly used phono-

logical awareness tasks, phoneme reversal

and

sound categori-

zation would seem

to

place

the

greatest demands

on

working

memory. Should we view these tasks as measures of phonologi-

cal awareness, working memory, or some combination of both?

Practical Implications

Reading skill has been shown to be related to measures of

phonological awareness, phonological receding in lexical ac-

cess, and phonetic receding in working memory. Determining

whether

each kind

of


is

related

to

read-

ing independent of the other kinds of phonological processing

is a first

step

in constructing a phonological battery that could

be

used

to

identify children

who are at risk of

reading failure

even

before reading instruction has commenced. For example,

based on previous studies, it might be assumed that prereading

measures of phonological awareness, phonological

receding

in

lexical access, and phonetic receding in working memory each

correlate with first-grade reading at the .3 level. Depending on

their degree of interdependence, a battery that includes mea-

sures of each of the three kinds of phonological processing

could account for a modest 9% (completely overlapping mea-

sures) to an astonishing 81% (completely nonoverlapping mea-

sures) of the variance in first-grade reading.

In addition to the practically important issue of

identifying

children

at risk for

reading

failure,

another implication

of the

question about the number of latent phonological abilities con-

cerns training programs

for

enhancing

the

acquisition

of

read-

ing skills. If, for

example, there should turn

out to be

basically

three distinct phonological abilities, each may represent a po-

tential locus of intervention. Alternatively, if there should turn

out to be basically one general phonological ability, then train-

ing programs should probably be directed at improving that

ability.

Empirical Studies

We know

of only a

handful

of

studies that address relations

among measures of phonological awareness, phonological re-



PHONOLOGICAL PROCESSING

AND READING

207

coding in lexical access, and phonetic receding in working

memory. With

two

exceptions (Blachman, 1984; Mann, 1984),

these studies have addressed relations between

(a)

phonological

awareness and phonetic

receding

in working memory, or (b)

phonological

receding

in lexical access and phonetic

receding

in working memory,

Mann and Liberman

(1984)

gave a syllable counting task as

a measure of phonological awareness and a memory span test

for phonemically nonconfusable word strings as a measure of

phonetic receding in working

memory

to

kindergarten preread-

ers. The

partial correlation

we

calculated between these

two

measures after holding IQ constant

was .32

(p < .01).

We

car-

ried out a multiple regression of first-grade reading scores on

IQ, syllable counting, and memory for word strings,

which

yielded an

R

2

of .25

(p

<

.01). With

IQ

held constant, reliable

proportions

of

variance

in first-grade

reading were accounted

for by syllable counting ft = .32, p < .01) and word string mem-

ory

ff = .31, p < .01).

In

sum, performance

on a

measure

of

phonological

awareness

was

related reliably

to

performance

on

a measure of phonetic recoding in working memory, yet both

measures contributed to predicting first-grade reading perfor-

mance.

Similarly, Goldstein (1976) reported a partial correla-

tion

holding IQ constant between a composite measure of

pho-

nological awareness (segmenting and blending) and memory

span of.

47, p<

05,

Mann (1984) gave a phoneme reversal task, a word string

memory task, and a letter

naming

speed task to kindergarten

prereaders. We calculated partial correlations with IQ held con-

stant

of . 11

(as) between phoneme

reversal and

word string

memory, -.09

(ns)

between phoneme reversal

and

letter nam-

ing

speed,

and -.11(ns)

between word string

memory and

letter

naming speed. These partial correlations indicate that perfor-

mance

on

these measures

is not

related

at

beyond-chance levels.

We

carried out a multiple regression of first-grade reading

scores

on

phoneme reversal, word string memory,

and

letter

naming speed, which yielded an

R*

of .74 (p < .001). With IQ

held

constant, reliable proportions of variance in first-grade

reading were accounted for by phoneme reversal {S

-

,61,

p <

.001) and by word string memory (0

=

.39,

p<

.001), with letter

naming speed approaching significance (0 = —.12, p < .1).

Blachman

(1984)

has reported similar results for measures of

phqnological awareness (segmentation and rhyming) and pho-

nological recoding in lexical access (naming speed for objects,

colors,

and

letters).

She

concluded that

the

measures were

tap-

ping different aspects of

linguistic

processing, each of which was

predictive of reading skill.

Naming

speed measures of phonological recoding in

lexical

access have been found

to be

related

to

span measures

of

pho-

netic recoding

in

working memory

by a

number

of

investigators

(Mann, 1984; Spring, 1976; Spring & Capps, 1974; Spring &

Farmer,

1975; Spring

&

Perry, 1983;Torgesen&Houck, 1980).

For

example, Spring and

Perry

(1983)

reported

a

correlation

of

.57

(p<

.01)

between digit naming speed

and

memory

for

pic-

tures with

nonrhyming

names

for a

mixed group

of 30

reading

disabled and nondisabled children.

Summary

The issue of the interrelations among measures of phonologi-

cal

awareness, phonological recoding

in

lexical access,

and pho-

netic recoding

in

working memory

is of

theoretical

and

practi-

cal importance.

The

theoretical importance

of

this issue

is

whether there

is

empirical support for distinguishing phonological awareness,

phonological recoding in lexical access, and phonetic recoding

in

working memory as separate phonological

skills

or kinds of

processing,

or whether they are manifestations of a single skill

or kind of phonological processing. The studies we have re-

viewed

suggest that phonological skill is to some degree general

across tasks that purport

to

measure awareness, recoding

in

lex-

ical access,

and

recoding

in

working memory.

However,

this gen-

erality

is not

complete,

and

empirical support for distinguishing

phonological awareness and phonological recoding in working

memory was found in

their independent contributions

to the

prediction

of

reading ability.

The practical importance of the issue of interrelations among

measures

of

phonological processing concerns

(a)

predicting

reading

difficulties

even

before reading instruction begins,

and

(b) identifying loci

for

possible training interventions. The com-

bined predictive power of measures of phonological

awareness,

phonological receding in lexical

access,

and phonetic recoding

in

working memory can be considerable. Mann

(1984),

for ex-

ample,

accounted

for

almost three-fourths

of

total variance

in

first-grade reading with three phonological tasks administered

in

kindergarten. In addition, the fact that phonological aware-

ness and phonetic recoding in working memory each accounted

for unique variance in first-grade reading when both were used

as predictors suggests that each should be viewed as a potential

locus of remedial efforts.

General

Discussion

We began this article by distinguishing three kinds of phono-

logical processing: phonological awareness, phonological recod-

ing in

lexical access,

and

phonetic recoding

in

working memory.

We have addressed

two

major interdependent issues:

the

nature

of phonological processing and the nature of its causal relations

with the acquisition of reading skills. In this section we (a) sum-

marize

for

these

two

issues

the major

empirical

findings from

our

review,

(b)

identify

important gaps in current knowledge

and

issues

to be

resolved,

and (c)

propose

the

means

by

which

these gaps and unresolved issues can be addressed in

future

re-

search.

Nature of Phonological Processing

Our interest in the nature of phonological processing is

fo-

cused

on the

question

of

whether phonological awareness, pho-

nological recoding in lexical access, and phonetic recoding in

working memory represent distinct kinds of phonological abili-

ties. Although

we

cannot answer this question with

any

degree

of certainty,

we can

provide

a partial answer.

Skill

at phonologi-

cal processing is to some degree general across tasks that pur-

port to measure phonological awareness, phonological recoding

in lexical access, and phonetic coding in working memory. Fur-

ther,

the

generality

of

phonological processing skill goes beyond

that which

may be

accounted

for by individual differences in

general cognitive ability. These conclusions are based on finding

significant

interrelations

among

tasks that purport

to

measure



208

RICHARD K.

WAGNER

AND

JOSEPH K. TORGESEN

each

of UK

three kinds

of

phonological processing after holding

IQ constant

However, the generality of skill at phonological

tasks

is not

complete,

and

there

is an

empirical basis

for

distin-

guishing phonological awareness from phonetic receding in

working

memory: Tasks that measure each of these two kinds of

phonological processing uniquely account

for

variance

in

later

reading

skill.

There are at least two means by

which

our understanding of

the nature of phonological processing might be advanced. The

first is to give a relatively large number of children tasks that

measure each of the three kinds of phonological processing, ide-

ally

on several occasions over the course of their early develop-

ment of phonological

skills. Alternative models

of the

nature

of

phonological processing could be tested

formally

with confir-

matory factor analysis on the basis of their accounting for ob-

served

covariances among the phonological processing mea-

sures.

Plausible models

of

the nature of phonological processing

to

consider include (a) a

general

ability

model,

which proposes

that performance on the three kinds of phonological processing

tasks derives from

one

latent phonological ability;

(b) an

aware-

ness versus

use

model, which proposes that performance on


tasks

and on

tasks

measuring the use of

phonological information in lexical access or in working mem-

ory derive from separate latent phonological abilities; and (c) a

specific ability model, which proposes that performance on the

three kinds

of

phonological tasks derives from separate latent

phonological abilities. Developmental changes in the nature of

phonological processing could be examined by comparing re-

sults across

multiple

administrations

of the

measures.

A

second means by

which

our understanding of the nature of

phonological processing could be increased is to look for re-

lations between particular kinds of phonological processing and

specific aspects of reading that should, in theory, be related to

them. For example, one might expect

that phonological

aware-

ness, especially in the form of segmenting and blending skill,

would be particularly salient to the acquisition of sound-based

reading skills

at the

word level. Measures

of

phonological aware-

ness would thus be better predictors of performance in reading

programs that emphasize a phonics

approach

than of perfor-

mance

in

reading programs that primarily

use a

whole-word

or

basal reader approach. Furthermore, there is no reason to ex-

pect direct relations between individual differences in phono-

logical awareness and reading comprehension.

5

Crowdert 1982) has proposed an account of the relations be-

tween

phonological processing and reading that also has im-

plications

for

differential relations between various aspects

of

phonological

processing and reading. He

suggests

that

when

a

word is encountered, lexical access is obtained very rapidly by

activating

an abstract phonological representation associated

with the

visual

representation of the word. In addition, as a re-

sult

of

subvocal

articulatory processes, the

word

is

phonetically

coded in short-term memory right after lexical access occurs.

Because

lexical access

can

occur before words

are

actually

placed in working memory, quite a bit of comprehension can

occur

without analyzing words stored

in

working memory.

However, storing word strings

in

working memory

is

important

for tasks such as resolving

pronomial

referents, following con-

voluted syntax, and making sense of difficult to comprehend

material, tasks that require examining relations among words

in complete phrases. Thus, although efficiency of phonetic re-

coding to maintain items in working memory may not be re-

lated

to

comprehension performance

for

easy material,

for

cer-

tain kinds of difficult text,

efficient

phonetic receding may be

crucial. For reasons we have outlined previously, the efficiency

of phonetic receding in working memory should also be related

to the accuracy of initial attempts at using word attack skills,

but might not be as predictive of the eventual speed of decoding

highly

familiar words.

The existence of specific relations between certain aspects of


and of

reading could

be

determined

by administering measures of several

aspects

of phonological

processing (e.g., awareness, receding in lexical access, and re-

coding

in

working memory)

and of

reading

(e.g.,

word analysis,

word recognition,

and

comprehension).

If

specific relations

were

found, they would provide

an

empirical basis

for

distin-

guishing the

different

aspects of phonological processing skill.

Causal

Relations Between

Phonological Processing

Skills

and the Acquisition

of

Reading

Skills

We have reviewed two major

sources

of evidence about causal

relations between phonological processing skills and the acqui-

sition of reading skills: longitudinal correlational studies and

training studies.

On

the

basis

of longitudinal correlational studies, we con-

dude that phonological awareness plays a causal role in the ac-

quisition of reading skills. There is considerable evidence for

such

a relation from a number of longitudinal correlational

studies,

but not

enough

to

determine whether similar causal

roles exist for phonological receding in lexical access or pho-

netic receding in working memory. However, the description

just

given

of the


process-

ing and the acquisition of reading skills is probably incomplete,

as it

neglects

a likely causal role for learning to read in the devel-

opment of phonological skills. The longitudinal correlational

studies we reviewed

simply

were not designed to determine

whether learning

to

read plays

a

causal role

in the

development

of

phonological abilities. Further, the results of our reanalysis

of

Lundberg

et al.'s (1980) data are consistent with the view that

learning to read plays a

nontrivial

causal role in the develop-

ment of phonological abilities.

The

training

studies

that have been carried

out to

address

the casual relations between the development of phonological

abilities

and the

acquisition

of

reading skills have yielded mixed

results. There

are at

least three important

reasons for

this out-

come. Before introducing these reasons, we must first reintro-

duce two rationales for expecting phonological skills to be use-

ful

in

learning

to

read.

The first rationale is provided by Mattingly (1980), who has

argued

that

a child with phonological awareness is

likely

to view

our system of writing as a sensible way of representing one's

language. Otherwise, the patterns of letter-sound correspon-

dences will seem strange and arbitrary. The second rationale

Stanovich, Cunningham, and Feeman (1984) used path analysis to

show that phonological awareness affects comprehension only indi-

rectly, through

its

influence

on

decoding speed.



PHONOLOGICAL

PROCESSING AND

READING

209

starts

with

the idea that beginning readers have three basic tasks

to

perform.

They must (a) decode a string of visually presented

letters,

(b)

store

the

products (i.e.,

the

sounds

of the

letters)

in a

temporary

store,

and (c)

blend

the

contents

of the

temporary

store to form words (Baddeley, 1979, 1982;

Torgesen

et al., in

press). Phonological skills, in the form of efficient use of phono-

logical codes to store letter sounds, enable the beginning reader

to apply the maximum amount of processing resources to the

difficult task of blending sounds to form words. Whereas these

rationale suggest that the effects of training in phonological abil-

ities should be largest very early in the acquisition of reading

skills, none of the large-scale phonological training programs

we reviewed began training until well after reading instruction

had

begun.

A second possible reason for the mixed outcome of training

studies is that in many cases, there was no direct assessment of

whether the training affected the targeted phonological skill at

all; the effectiveness of training was evaluated only in terms of

its

effects

on subsequent reading skill. The problem is that a

phonological training program may or may not improve read-

ing skills, and for reasons that are unrelated to the theoretical

relations between the phonological skill and reading (Steinberg,

1983).

A third possible reason for the mixed effects of training stud-

ies is that phonological abilities may be

difficult

to train. Con-

sider how one might train phonological awareness. The typical

approach is to present exercises requiring children to work with

individual

phonemes

in isolation and

then perhaps

to

blend

them together to form words. Yet in everyday speech, phonemes

are coarticulated, and the interpretation given of a target pho-

neme

depends on the immediately preceding and succeeding

phonemes. Thus,

there will

be differences

between what

is

expe-

rienced in everyday speech and what is experienced in phono-

logical training

programs,

and

these

differences

may be

non-

trivial.

There have been

two

approaches

to

addressing this problem,

each

of which attempts to simplify the phonological task to be

trained.

The first approach

teaches segmentation

and

blending

of

syllables rather than

of

phonemes, because syllables appear

to be more accessible to early readers than phonemes.

Gleitman

and

Rozin(

1973,1977;

Rozin&

Gleitman, 1977) took this ap-

proach in a training program for inner-city children. A rebus

approach was used in which syllables were represented by Dic-

tographs (e.g., an outline of a bee for the syllable "be") or by

letter

sequences. Children were trained

to combine

picto-

graphic representations of syllables

to

make words. Preliminary

results suggested that children could learn to use the system

easily, and thus got practice at segmenting and blending they

might not have otherwise. However, it was not demonstrated

that benefits

of

training extended

to

phonemic segmentation

or

to reading in the absence of the rebus. We are not aware of any

more recent studies of the effectiveness of this particular

ap-

proach.

The second approach has been to provide concrete materials

to help train children to segment and blend phonemes. Bradley

and Bryant's (1985) use of plastic letters is one example, al-

though whether the concrete materials need be letters is at issue.

Elkonin

(1971, 1973) has devised a program to train children

to

segment words into phonemes.

In the first

stage

of

training,

subjects are shown pictures of objects. Below the pictures are a

series of unmarked connected squares, one representing each

sound of the word. Children are taught to say words by pro-

nouncing

each sound

in

succession while placing

the

squares

in

their proper positions. In the second stage, the concrete materi-

als are removed, and in the final stage, the child

does

not verbal-

ize the

sounds.

A

series

of

training studies were carried

out

with

6-year-old nonreaders

who

were unable

to

segment words into

phonemes before training. After training, the children could

segment words into phonemes.

After

over

a decade of

research,

we

know more about

re-

lations between phonological processing

and

reading than

we

do

about relations between reading

and

just about anything

else. Yet perhaps the most important fruit of this labor is the

realization that it is no longer enough to ask whether phonologi-

cal skills play a causal role in the acquisition of reading skills,

or

even

whether learning to read plays a causal role in the devel-

opment of phonological skills. Rather, the question we must

now

ask is both more complex and more to the point: Which

aspects of phonological processing

(e.g.,

awareness,

receding

in

lexical access, receding in working memory) are causally re-

lated to

which

aspects of reading (e.g., word recognition, word

analysis, sentence comprehension) at

which

point

in their

code-

velopment,

and

what

are the

directions of these causal relations?

Not one of the

studies reviewed

is of the

scope necessary

to

answer

this question. What is required are longitudinal correla-

tional studies that obtain multiple measures of each kind of


and

reading

at a

number

of

points

in

time, as

well

as training studies that obtain similar kinds of

measures.

We describe one admittedly speculative proposal

(Wagner,

1986a) in order to give an example of what an answer to the

question just posed might entail. The two-part proposal is based

on a

quantitative synthesis

of

16

longitudinal

correlational

and

training studies with a combined N > 1,200. It is largely an

integration of the views of Perfetti, Beck, and Hughes (1981)

and

Baddeley (1979, 1982).

First,

it is

proposed that

the

ability

to

blend phonemes plays

a causal role in the acquisition of beginning reading skills. How-

ever, it is not the simple awareness that phonemes can be

blended

to

form words that matters,

but

rather

the

ability

to use

phonological codes to efficiently store the sounds of letters and

letter combinations when blending sounds to form words.

Evidence from the quantitative analysis that blending rather

than

segmenting plays

an

important causal role

in the

acquisi-

tion of reading skills comes from the fact that there are reliably

stronger causal relations

for

blending than

for segmenting in the

acquisition of word analysis

skills.

Evidence that use rather than

simple awareness

is

what matters comes

from the fact

that

blending tasks are highly correlated with measures of use of

phonological information either in lexical access or in main-

taining information in working memory, yet segmenting tasks

are not. Finally,

evidence

that blending phonemes as opposed to

syllables is what matters comes from the reliably stronger causal

relations for tasks involving phonemes than for tasks involving

syllables in the acquisition of word analysis

skills.

Second, it is proposed that the acquisition of reading

skills—

especially those measured

by

word analysis

tasks—plays a

causal role in the development

of

both awareness that words can



210

RICHARD K. WAGNER AND JOSEPH K. TORGESEN

be

segmented into phonemes and efficient

phonetic

receding to

maintain information in working memory.

Regarding phonetic

receding, it is proposed that reading

instruction

and practice

facilitate the

efficiency

with

which phonological

codes

are

re-

trieved and paired

with

letters and the efficiency

with which

the

codes can be

maintained

in working memory

once

they have

been retrieved.

Evidence

that

reading

plays

a causal role in the development

of awareness

that

words can be

segmented

into

sounds comes

from

the

fact that

the acquisition of word

analysis skills

plays a

reliably

stronger

causal role in the development of segmenting

ability than blending

ability.

The quantitative analysis also pro-

vided evidence of a causal

role

for

reading

in the

development

of efficient phonetic

receding in working memory.

Whether

this particular

proposal about causal relations

be-

tween

phonological

processing and reading or some other pro-

posal ultimately will be supported by further

empirical

work is

unimportant.

What

is important is that our future

work

should

begin to answer the question of how phonological

processing

and reading are

related

causally, in a framework

that allows

different answers for

different

kinds of

phonological

processing

and reading, at

different points

in their

codevelopment.

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Revision

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the nature of phonological processing and its causal role in the acquisition of reading skills

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