top-down influences on the time-course of visual attention:

Top-down influences on thetime-course of visual attention:

Maria V. Falikman

Lomonosov Moscow University

When the attentional blink meets word superiority effect

Research supported by the Russian Fund for Basic Researches, grant # 03-06-80191

Where cognitive science was born…

“… “… I went away from the symposium I went away from the symposium with the strong conviction, more with the strong conviction, more intuitive than rational, that human intuitive than rational, that human experimental psychology, theoretical experimental psychology, theoretical linguistics, and computer simulation linguistics, and computer simulation of cognitive processes were all part of of cognitive processes were all part of a larger whole...” a larger whole...”

(George Miller on the (George Miller on the 1956 MIT Symposium)1956 MIT Symposium)

Types of processing (information flow)

Top-down (conceptually-driven)

Bottom-up (data-driven)

Stimulus

Task,Experience

Conscious percept

Top-down influenceson visual attention

Unconscious (implicit) Conscious (explicit)

Contextual cueingPriming (+/-)

Schemata

...

Strategic regulation of perceptual task

accomplishment

Context-based or

memory-based

Goal-directedor

task-dependent

VISUAL PRESENTATION

Rapid Serial Visual Presentation (RSVP)

RA P I DS ER I A L

RA P I DS

A L

The Attentional Blink (AB) under RSVP conditions

RA P I DS ER I A L


RA P I DS

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RA P I DS ER I A L


RA P I DS

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RA P I DS ER I A L


RA P I DS

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ER I


RA P I DS

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ER I


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Probe relative serial position

% C

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Experimentalcondition

Controlcondition

The AB effect replicated: Results of the standarddual-task RSVP experiment (2000)

Why a blink?

Attentional gate model

Attentional dwell-time

theory

Two-stage model

Interference model

Object substitution

theoryCentral

interference theory

Perceptual system

reconfiguration

Hybrid models

Amnesia!Blindness!

Early selection / filter (Broadbent, 1958)

Models of selective attention and models of its blink

Attentional gate(Raymond et al, 1992)

Late selection (Deutsch & Deutsch, 1963)

Pertinence model (Norman, 1968)

Interference model (Shapiro et al, 1994)

Two-stage model(Chun & Potter, 1995)

Multiple selection (Johnston & Heinz, 1979)

Flexible selection (Yantis & Johnston, 1990)

“Smart selection”(Shapiro & Luck, 1999)

“Intelligent filtering system”(Enns et al, 2001)

Perceptual cycle (Neisser, 1976)

Reentrant model (Di Lollo et al, 2000)

Attention for action

Quo vadis?

Attention as an aspect of action

D.A. AllportO. NeumannA.H.C. van der Heijden

a set of “task-related

mechanisms” (e.g. Deacon & Shelley-Tremblay, 2000)

Gippenreiter, 1983 [rus]1986

or

The prototypical “bottleneck” model

Early stage LC-stageT2 . . .

T2

Early stage LC-stageT1 T1 report

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The AB effect: my old results again

The AB effect might be due to the inability of perceptual system to obtain further information until the previous goal-directed act (conscious

target identification) is completed.

Then, the AB could be modulated through the change of the size of the observer’s activity “units”:

if we incorporate the 1st target into a larger perceptual “object”, the AB will probably not interrupt perception until the end of the act.

““The difficulty is not to combine stimuli, but rather to deal with them The difficulty is not to combine stimuli, but rather to deal with them independently at the same time... capacity limits occur where stimuli independently at the same time... capacity limits occur where stimuli have to be kept apart, not where they have to be combined…”have to be kept apart, not where they have to be combined…”

(Neumann, 1987, p.363)(Neumann, 1987, p.363)

“Attentional units” larger than letters?

WWOO

RRDD

SS

Stimuli examples: Russian letters

WRITTENPRINTED

The word superiority effect

Better performance on letters within a word than on random letters:

• faster recognition

• more letters perceived within a brief (10 ms) presentation

““I find it takes about twice as long to read (aloud, as fast I find it takes about twice as long to read (aloud, as fast as possible) words which have no connexion as words as possible) words which have no connexion as words which make sentences, and letters which have no which make sentences, and letters which have no connexions as letters which make words. When the words connexions as letters which make words. When the words make sentences and the letters words, not only do the make sentences and the letters words, not only do the processes of seeing and naming overlap, but by one mental processes of seeing and naming overlap, but by one mental effort the subject can recognize a whole group of words or effort the subject can recognize a whole group of words or letters, and by one will-act choose the motions to be made letters, and by one will-act choose the motions to be made in naming them, so that the rate at which the words and in naming them, so that the rate at which the words and letters are read is really only limited by the maximum letters are read is really only limited by the maximum rapidity at which the speech organs can be moved...” rapidity at which the speech organs can be moved...”

(Cattell, 1886, p.64).(Cattell, 1886, p.64).


Further explorations:

Reicher, 1969

Wheeler, 1970

McClelland, 1976

...


R


RW O D

Some examples of “mutable” words(main experimental session)

...P I L O T #

...S P R I T E #

...B R I D G E #

I

…W A T E R #

L

…F A V O R #

G

…B R I D E #

the AB is due to a certain bottom-up controlled limitation (“a bottleneck”),

Hypothesis

it is rather shaped by top-down processes in the information processing system,

it will leave its signature on the observers’ performance on mutable words.

it will either disappear or be diminished in the word-reading task.

IFIF

IFIF

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Comparison of correct reports on separate letters in mutable words and on a probe X under “standard”

AB conditions (2000)

Word identification

point?

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Subject 6

Subject 17

Mean

There is a blink on mutable words! Individual differences.

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Mentioninga positionfor all wordstrings

And what about the overall result?

The ACTUAL experimental design:

Concluding control

session:

identify the type of a white letter and name three letters following

it (after Weichselgartner

& Sperling, 1987)

Main experimental

session:

identify the type of a white letter and read a word beginning with

this letter

Preceding control

session:

identify the type of a white letter and name three letters following

it (after Weichselgartner

& Sperling, 1987)

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Preceedingsession

Concludingsession

Strategic change: Results of framing sessions

There could be no strategic changes! Individual differences again.

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Subject 16 Subject 2

Control experiment: No practice effects

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No words noticed between!

Word superiority in written vs. printed T1 task

T1 type identification

in the concluding

control session:

90.4 2.9%

T1 type identification in the word-

reading session:

96.2 2.4 %

T1 type identification

in the preceding control

session:

89 3.9%

Significant!(p<0.0001)

Significant!(p<0.0001)

Subjective dual-task estimation through

the experimental sessions (% of subjects)

Preceding Preceding sessionsession

Concluding Concluding sessionsession

Main sessionMain session(word-(word-

reading)reading)

Two separate tasks A single whole

The AB seems to depend on the task and on subjective strategies.

But strategies serve for achieving a goal,

the goal is to report on T1 etc.

For that, verbal working memory consolidation or encoding is essential!

and

Working memory consolidation:

neurophysiological data P300 - a late ERP component, a correlate of working memory encoding and attentional load

T1: repeats the dynamics of the AB after T1 identification (McArthur et al, 1999)

T2: suppressed for missed probes during the AB (Vogel et al, 1998; see also Rolke et al, 2001)

A possible model: two-stage compatible

S

P

H

A

R

E

PP

HH

PP HH

T1 + “word” WM encoding

ReportPP HH

RR

......

PP ......

T1 WM encoding...

...

Not yet!

RR

AA

Time to start WM encoding:- I got the word! - My VSTM buffer is full!

Perceptual task accomplishment can in principle be organized in such a way, that, given a sufficient load of that limited-capacity block or process, the AB would either disappear or diminish and shift from its critical temporal interval.

These changes can be determined both externally (by task conditions and requirements) and internally (by subjective strategy), that is characteristic for any human activity.

Conclusions

if T1 is an addition task (e.g. 2+3)

Hurrah!Hurrah!

Recent results working for this hypothesis:

and T2 is an answer

(seems to be… 5!)

there is no blink!

(Kunar & Shapiro, in preparation)

Our results directly suggest that the attentional blink deficit does not represent merely the workings of a fixed capacity-limited mechanism for the perception of events occurring over time, but rather the structure of actions a subject has to perform in order to accomplish a given task.

Conclusions

Pronounceable pseudowords

Missing controls?

- in progress Random strings, instruct to read words

- in progress

Words with ambiguous endings? - Thanks to Molly Potter for the brilliant idea! To be performed.

More ideas? - Please keep them in mind until the discussion...

Visual search?

Prospect:

Crowding?

Metacontrast masking?

Unconscious perceptual priming?

- YES (Fine, in press)

Attentional switching (gating paradigm)?

Special thanks to

Our programmers:

Ekaterina Pechenkova (Moscow University) for collaboration and invaluable discussions

Suren Sagiyan

Dr. Valeriy Romanov, Dr. Yuriy Dormashev (Moscow University) for inspiration of the AB research

George Kouryachy

Thank you for your attention

that hopefully didn’t blink

(owing to the top-down regulation!)

top-down influences on the time-course of visual attention:

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