Infant perception 2

Question 1

What is the difference between behavioural and imaging techniques?

Answer 1

behavioural require action, imaging is passive- sometimes hard to show novelty or preference

Question 2

Behavioural (5) techniques

Answer 2

high amplitude sucking (HAS)
conditioned head turn (CHT)
head turn preference (HTP)
preferential looking
eye tracking

Question 3

HAS

Answer 3

suck triggers sound, suck less as habituate to sound then change makes rate change if perceived
+: good for newborns, active indication of interest
-: high attrition and if increased sucking rate- lost attention or not perceived?

Question 4

CHT

Answer 4

suitable only for older babies; requires movement, brightly coloured toy to keep attention straight ahead, then conditioned to turn to particular stimuli (eg speech), reinforced by picture//toy during conditioning phase
eg Kuhl 2006 144 discounted out of 170 due to time

Question 5

HTP

Answer 5

child looks between different lights; sound played while looking at to light, stops when stops looking. time spent looking indicates preference of sound – or does it show novelty?!

Question 6

Preferential looking

Answer 6

measure total looking time and decide which one is preferred

- familiarity or novelty? McMurray and Aslin 2005- inconclusive results trying to distinguish

Question 7

Eye tracking technique

Answer 7

Quantitative measure of attention to different stiuli or actiosn presented on the screen (pref looking)
- non invasive and used for range of experiments

Question 8

Imaging (3)

Answer 8

ERPs
fMRIs
Baby MEG
- reduced in cost and availability, less attrition, effortful to run and highly trained, but exps are highly controlled

Question 9

ERPs

Answer 9

Record brain electro activity as EEG, picked up on scalp and amplified with excellent temporal resolution
- odd ball paradigm; low prob mixed with high prob intermixed. evoke potentials, not spontaneous- correlate directly with stimulus

Question 10

ERP responses

Answer 10

MMN: mismatched negatively; discriminate neurally- subconscious results
P300: reflect processes involved in stimulus evaluation and categorisation
N300: reflect unexpected result
+: passive, all ages, can compare, spectral waves can be directly linked to cognitive processes
-: poor spatial res, difficult to get info to regions specifically

Question 11

fMRI

Answer 11

difference in test conditions by blood flow to particular region- very good spatial resolution BUT total absnece of movement, noise or blinking- not suitable. but some success with young children: Biasill (3m to emotional sounds)

Question 12

Baby MEG

Answer 12

magnetoencephalography- electrical activity up to 100,000 neurones in a specific area
+: combines spatial res and much better than fMRI, non invasive, can be used when sleeping and infant can move head within helmet, can be used for interaction (eg washington labs)
-: not very available,

Question 13

perceptual pre-requisites of speech learning

high sensitivity to..

Answer 13

sound distinctions for phonemic contrasts, congruence between auditory ad visual cues
- sub-phonemic differences that may be relevant (eg allophonic distinctions)

Question 14

perceptual pre-requisites of speech learning

low sensitivity to…

Answer 14

variance in speaker tone (perceptual constancy), speech sounds not relevant to ambient language, within category variation

Question 15

are these present from first weeks?

Answer 15

innate categorical perception= high sensitivty to phonemic distinctions by 6m.
perceptual constancy at 4-6m, 4.5m speechread,

Question 16

Eimas 1971:

Answer 16

HAS in 104m infants, hear cross cat differences but to within category with longer VOTs- high sensitivity to phonemic distinctions and low sensitivity to within-category distinctions
thus INNATE CATEGORICAL PERCEPTION

Question 17

Kuhl 1979

Answer 17

Evidence of low-sensitivity/ perceptual constancy: HTP, 4-6m, for vowels; transferred to new tokens differing in speaker and pitch contours- equivalence class

Question 18

Kuhl and Meltzoff 1982:

Answer 18

attunement to AV correspondences using preferential looking for 4.5m: spend longer looking at face matching articulation

Question 19

Werker ad Tees 1984

Answer 19

Evidence of attunement to native phon cats at 6m desensitise to non-native changes
- infants are born able to discriminate all contrasts. neural commitment to native language occurs at 6-12m

Question 20

evidence against presence in first weeks:

Answer 20

adsf

Question 21

animals:
Kuhl and Miller 1978;

Eimas 1971

Answer 21

Kuhl and Miller 1978; chinchillas can discriminate human phonetic barriers
Eimas 1971: basing this evidence on cochlear rather than innate lingustic neural structures.

Question 22

lack of early sensitivity to native: Eilers and Minfrie 1975

Answer 22

evidence of early sensitivity to native contrasts- counters universal sensitivity

Question 23

further attunement: Kuhl 2006

Answer 23

evidence of further attunement to native phonemic contrasts with experience: 6-12m CHT, taught 32 infants in japan and usa r/l contrasts… shows neural commitment to native language

Question 24

ongoing sensitivity to some non-native contrasts:

Meta analysis in 2006 of 9 experiments on contrasts- not conclusive.

Answer 24

7 studies decline in performance with age; 2 didn’t
No decline for US infants discrimination in african clicks (Best, sithole 1988)
No decline for french infants tested on non native contrasts (falsified hypothesis) (polka et al 2001)

Question 25

Early sensitivity to within-category distinctions

Answer 25

at 3-4m infants show graded perception of VOT (miller and eimas 1996)
at 6m discrimination of within-category difference along VOT continuum when tested with sufficiently sensitive tasks (mcmurray and aslin 2005)

Question 26

mechanism?

Answer 26

statistical learning; Maye, werker and gerken 2002: tested 6-8m using preferential looking, only children from bimodal exposure group discriminated
SO infants learn phoneme categories via SL sensitive to distributional properties of phonetic input