Methoden der Sprachwerbsforschung

(mit einigen Folien aus „EXPERIMENTAL PARADIGMS IN DEVELOPMENTAL PSYCHOLINGUISTICS“ von Zsuzsanna Schnell (Institute of Psychology,

University of Pécs

Typology of methods

Distinction based on:

• 1. Sample: Longitudinal vs. Cross sectional• 2. Method: Observation based (diaries, questionnaires) vs.

Experimental• 3. Temporal aspect: Pre-natal vs. Post natal• 4. Linguistic behavior: Pre-verbal vs. Verbal

Research methods in the study of language development

• Diaries and parental reports: as early as 18th century – own children, diaries.• remain a valuable source, !: misleading: tempted to write down unusual,

or interesting, and not the ordinary but relevant.• new version: McArthur Communicative Development

Inventory (CDI) by Larry Fenson et al.

• checklist prepared by psycholinguists distributed to parents• has been validated in laboratory settings.

Advantages vs. Disadvantages

• ADVANTAGES: natural setting, family context• fast, no funding needed• no training required• DISADVANTAGES: not suitable for older children,

whose lg use is more complex• may be misleading• ALL IN ALL: If used correctly, the home-based

parental questionnaire is a reliable indicator

Observational data

• first motivation: reconcile allegationsof revolutionary nativism: UG, LAD• first: tape recordings transcripts.• Roger Brown 1960-ies, Harvard: longitudinal study, studying the lg dev.

of Adam, Eve and Sarah.

transcripts fostered our understading of child grammar, acq. of basic sentence structures

• still a major research design

Advantages vs. disadvantages

ADVANTAGES:• rich source of data. • focus on environmental factors and on influence of

socialization (effect of parental input).

DISADVANTAGES: longitudinal studies are - confined to a small n. of children (luckily results are representative of

all children)!:transcripts may not include all situational factors, social and contextual

effects- Difficulties arise from individual encoding – devising their own system,

rendering it unusable for others.

CHILDES – The Child Language Data Exchange Systemhttp://childes.psy.cmu.edu

• unified approach • standardization in research methods, • of recording and analyzing data on child language production.• 1980’s: Brian MacWhinney and Catherine Snow proposed setting up a

computerised data-base that would be available for the entire academic community.

CHILDES http://childes.psy.cmu.edu

• the database can be accessed worldwide, to which relevant material can be contributed in a standard format.

• today contains data from 22 lgs• on both first LA and second lg learning • from normally and from atipically developing children• from early mother-child dialogues to lengthy narratives,

monologues • prosody, stress, pause patterns, metalinguistic fators. • Allows initial assessment of hypotheses.

@UTF8@Begin@Languages: nl@Participants: 024 Patient, DIE Dieke_Lagers Investigator@ID: nl | frogstory | 024 | | | fs | | Patient | |@ID: nl | frogstory | DIE | | female | fs | | Investigator | |@Coder: Neeltje Verstegen*DIE: ja, wat gebeurt (e)r verder?*DIE: zullen we (een)s verder kijken?*024: een hond die ging # de jongen likken.%pro: $1*024: en die jongen kijk(t) [*] <zo naar> [?] buiten.%pro: $1%err: $5 kijk = kijkt*024: 0er viel een hond # viel van xxx.%pro: $1%err: $8*024: en in een keer valt die glazen pot.%pro: $1*024: [=! laughs].

Longitudinal vs. Cross-sectional studies

• Cross sectional studies: gather groups of children to assess their abilities

• compare performance of groups.• ADVANTAGES: allows to obtain a great deal of data in a

short time, • large samples yield results that can be generalized.

• Cross Sectional or Longitud. studies can be either Observational or Experimental.

Observational studies

The researcher tries not to interfere with the subject’s natural use of lg.

a.) Naturalistic O.S. - focus on real-life situations linguistic socialization, env. factors shaping LA

b.) Controlled O. S. – laboratory setting and props are the same for all subjects (puppets).

Experimental studies

Do involve interference from the part of the researcher. • WUG test - Jean Berko Gleason ’50-ies – Elicited Production

experiment Using Nonce Words.• m.i.: when prompted by the linguistic context in which the

term appears, children will transform these so as to obey the grammatical rules.

• picture shown and is told it is called a „wug”. Then subject is shown another „wug” and told: „So now there are 2 of them.” And asked: „Now I have two…?” Expected answer: „wugS”.

• 2. Every day I „gorp”. Just like every day, yesterday I……….? „GORPED”.

13Berko (1958)

Observational vs. Experimental studies

• OS: we do not know for sure if plural marker „s” is consciously put there, or blind imitation

• ES: semi-controlled setting, eliciting the plural marker RULE application true status of grammatical markers

DISADVANTAGE of ES:• Rigidly controlled settings may mean difficulties, such

demands of the experimental task may distort validity and reliability of results.

• It is therefore important to verify that such patterns are present in natural speech.

PREVERBAL I.Pre-natal Studies of speech perception

Prenatal (fetal):from 6th month of gestationmethod: microphone placed outside the womb,

measure modifications in:a.) Cardiac acceleration/deceleration: fetus shows sensitivity to changes in stimuli (habituation)

b.) Fetal movement (kicking rate) corresponds to changes in stimuli (US)

PREVERBAL II. Post-Natal Studies of speech perception

HASP: High Amplitude Sucking Paradigm (e.g. Juszyk, 1997)?: categorical perception of infants capitalizes on natural sucking instinct

using sucking rate as measure of interest habituation / dehabituation

paradigm

…with older children• Conditioned head-turn paradigm (Polka, Jusczyk, Rvachew 1995) - with infants 6-18 months of age-a stimulus sound is presented repeatedly

• - Whenever there is a change in a stimulus, an electric toy (to the side of the child’s line of vision. ) is lit up and activated.

• Eventually the child learns to anticipate that sound changes provoke a visual display, and they will turn their head to look for it when hearing a sound change.

methods for studying comprehension …beyond speech (sound) perception

• preferential looking paradigm (Hirsh-Pasek – Golinkoff 1996). capitalizes on differential looking behavior when given a choice from 2 displays

child grammar: passive voice lexicon: pictures of objects, animals (nouns)

m.i.: child will look longer in the direction of the named object if they understand the word / construction.

if neither object corresponds to the experimenter’s label, then they will look at both stimuli for eqivalent periods of time.

the same holds if the baby does not know the word.

…in the verbal stages• elicited response, interviews (monologue, retelling an adventure>5

yrs).

Off-line techniquesmeasure comprehension by getting children a.) perform an action (act out)b.) retell the event after hearing a linguistic stimulusc.) picture pointing – subject is asked to point to the pic. that depicts the

action in the experimenter’s utterance. The dog pushes the cow vs. The cow is pushed by the dog (active vs. passive)

DISADVANTAGE: experimenter influences answers (multiple choice)- involves conscious decisions and reflections by the child (performance

limitations) (metalinguistic competence.)

On-line techniques I.- measure language processing as it occurs in real time.- e.g.: distinction between transitive vs. intransitive verbs.

- I. Task: to listen for a particular word, e.g. „DOG”. - The subject is asked to push a button as soon as they hear the target

word. - a.) The boy was out on a walk and he watched a DOG passing by.- b.) The boy was out on a walk and he watched to*a DOG passing by.- If they are sensitive to in-/transitive distinction, it will take longer to react

in the erroneous case (watched to* a DOG…)- because the processing of ungrammatical structures will take longer if

they have already acquired the correct grammatical rule.

On-line techniques II.- Non-invasive brain imaging studies: HD Event Related

Potential (ERP) Studies measuring electric activity in brain areas.

- Eye-tracking experiments (head-mounted and remote eye-tracking systems) (syntactic parsing, topicality, idiom research looking time – segmentation correlation).

- Reaction-time techniques: computers measure reaction time in milliseconds. Time correlates with parsing difficulties (gaden-path sentences).

Advantages vs. Disadvantagesof on-line methods

- ADVANTAGES: - fast, accurate, - reveals fine-grained differences in performance, - memory is not overburdened, does not require reflection, since it is

unconscious. - reveal competence off-line don’t (focus on comprehension)- online: investigates the interaction between competence and

performance factors.

- DISADVANTAGES: - difficult to design, - fallible, detail sensitive.

Conclusions

• Innovative Experimental techniques counterbalance the limitations of a purely observational research

• Experimentally gained data need to be complemented by observations of natural linguistic performance.

Literature:E. Blom & S. Unsworth (2010) siehe Lehrmaterialien

Gleason, J. B. - Ratner, N. B. (1998). Psycholinguistics. Harcourt Brace College Publishers. Orlando, FL.

Karmiloff-Smith, A. – Karmiloff, K. (2002). Pathways to Language. Harvard University Press.

Sowden, H. (2008). Developmental Psycholinguistics. On-line methods in children’s language processing. Language acquisition and language disorders series. John Benjamins, Amsterdam.

Head-turn preference procedure (Kemler Nelson, Jusczyk, Mandel, Myers, Turk & Gerken, 1995) (used with children 5-20 months old, but mainly with 6-12-month-olds)For this method we make use of a 3-sided booth. The child sits facing forwards on the parent’s lap in the middle of the booth. In the centre of the wall facing the child is a blue light that starts to blink at the beginning of the experiment. When the child looks at the light, it stops blinking, but a red light on either the left or right side of the booth then starts to blink. There are loudspeakers built into the wall behind the lights. As soon as the child looks at the light on the left or right, he will hear a speech sample. The sound stops if the child looks away for more than two seconds. So the length of the speech sample is dependent on how long the child continues to look at the light. When the sound stops, the blue light in front of him will blink again to attract his attention and the whole process starts again. By measuring the time spent listening to different speech samples, we can discover whether the child has a preference for one of them.

We use this method to find out whether children have a preference for (and thus listen longer to):their native language as compared to another language;grammatical as opposed to ungrammatical sentences;frequently-occurring as opposed to infrequently-occurring words;words with stress on the first syllable (“baby”) as opposed to words with stress on the second syllable (“giraffe”).

Baby Research Center Nijmegen

The Conditioned Head-Turn Procedure (CHT, Polka, Jusczyk, & Rvachew 1995)(between 6 and 10 months of age)Sitting across a table (on a parent’s lap) from an experimental assistant, the infant is shown brightly coloured toys to keep him/her interested and focused straight ahead. Speech stimuli are presented to the infant via an audio speaker placed at one side. The infant is taught to turn his/her head in the direction of the sound whenever there is a change in the speech stimulus. A correct head-turn results in visual reinforcement from the direction of the audio speaker; the experimental assistant also gives the infant social reinforcement via smiles and praise. Incorrect head-turns are not reinforced.A study using the CHT begins with a Conditioning phase, during which tokens from the background stimulus category are played repeatedly so that the infant gets used to that category of sounds (e.g., ba, ba, ba, ba). Then, the target sound (or sound category) is played (e.g., da), and after a short delay of a few seconds, the reinforcer (a lighted, moving toy bunny that plays on a set of drums) turns on, prompting the infant to make a head turn. This sequence is repeated a number of times so that the infant becomes conditioned to turn his/her head toward the bunny when he/she hears the change in sound from the background stimulus to the reference stimulus.

The equipment we use for measuring eye movements (the Tobii eye-tracker) consists of a computer screen with a built-in camera that takes pictures of your child’s eyes. Your child will sit on your lap and watch a short movie on the computer screen.While your child is watching the movie, we record his or her eye movements and later investigate whether and how he or she followed what happened on the screen and which aspects he or she paid most attention to.

Before the measurement can begin, your child will see a circle moving to different positions on the screen. In this first phase of the experiment it’s important that your child looks at the circles and doesn’t move around too much. In this way, the computer can register what your child’s eyes look like when he or she looks at different parts of the screen. This usually takes just one or two minutes. The main experiment then starts, during which your child will watch one or two short movies. Generally, each experiment lasts only a few minutes, but if your child becomes very restless, we can simply end the experiment.

The eye-tracker allows us to learn how babies perceive and process other people’s actions. The picture below is from a study where we investigated whether babies already know what various objects are used for. The pictures show the child watching as a person picks up a cup (the child’s eye movements are shown by a blue dot.) It’s very clear that the child has anticipated what the person is going to do!

Baby Research Center Nijmegen

Eye-tracking

Eye-tracking

Preferential looking paradigm (Hirsh-Pasek – Golinkoff 1996) (used with children aged 4-26 months old) One of the methods we use is the “Preferential Looking Paradigm”. We observe children’s eye movements while they watch a short movie either on a large TV screen or on a Tobii eye-tracker. The children sit on their parent’s lap. The parent generally listens to music via headphones so that he or she doesn’t influence the child in any way. The movies, in which the child either hears words, sentences or a story generally last no longer than 5 minutes. If a child hears the name of an object that is depicted on the screen, then he or she will automatically look at that object. For example, if the screen shows a dog on the right and a baby on the left and the child hears “Where’s the baby?”, then the child will look at the left side of the screen. In one of our experiments, we investigated whether children would also do this if they heard “Where is the “vaby”? It appears that in this situation children will look at the correct picture (the baby), but it will generally take a little longer and they will look at the picture for less time.Children also sometimes mispronounce words. For example, a Dutch word like “vis” may often be pronounced “tis”, and “vogel” may be pronounced “pogo”. But a word like “poes” won’t normally be pronounced as “voes”. It appears that how a word is pronounced depends on children’s perception of it: children easily notice the difference between “voes” and “poes”, but less easily the difference between “vogel” and “pogo”.

Baby Research Center Nijmegen

Switch procedure (Stager & Werker, 1997) (Variant of visual fixation procedure)

In the Switch procedure we measure the eye movements of young children while they are looking at a picture or some other visual display on a large TV screen. While they are looking at the screen, they hear various sounds, words or languages. The child sits on the parent’s lap, while the parent listens to music via headphones, so that he or she doesn’t inadvertently influence the child’s behaviour. Children can often hold a plastic toy during the experiment. The majority of experiments last for five minutes. The idea behind this procedure is for the child to listen to a word, for example, long enough that he or she no longer finds it interesting and looks away from the screen more and more frequently. This is also known as “habituation”. We determine the child’s interest based on how long he or she continues to look at the screen. When the child’s interest has decreased considerably, we let him or her listen to another word (that is sometimes very similar to the previous one). If children notice the difference between the new word and the previous one, then their interest should increase and they should once again spend more time looking at the screen.Our research using this procedure has shown that 10-month-olds are able to discern small sound changes at the beginning of words. For example, infants continuously heard the fictitious word “tos” and after a while gradually lost interest and spent less time looking at the screen. When they subsequently heard a new fictitious word “pos”, where the beginning of the word changed from “t” to “p”, the time they spent looking at the screen increased again.

Baby Research Center Nijmegen

Aufgabe v. 20.4.15

Lesen Sie das Kapitel von Johnson & Zamuner (S 73ff) in Blom & Unsworth (2010). Nennen Sie Vor- und Nachteile der Methoden.Erstellen Sie eine Zeitskala in Monaten von 0-24 aus der ersichtlich wird, welche Methoden in welchem Alter in Frage kommen (einschließlich conditioned head-turn procedure und high-amplitude sucking procedure, siehe Folien)Bereiten Sie mit zwei bis drei weiteren Teilnehmer(inne)n eine kurze (ca. 5 min.) Demonstration einer der Methoden in Form eines Rollenspiels vor. Achtung: Außer den beteiligten Personen (Kind, Mutter, Experimentator, Sprecher von Stimuli) brauchen Sie auch Requisiten (Licht, Spielzeuge).