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Categorical Representation of Facial Expressions in the Infant Brain
Author(s) -
Leppänen Jukka M.,
Richmond Jenny,
VogelFarley Vanessa K.,
Moulson Margaret C.,
Nelson Charles A.
Publication year - 2009
Publication title -
infancy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.361
H-Index - 69
eISSN - 1532-7078
pISSN - 1525-0008
DOI - 10.1080/15250000902839393
Subject(s) - psychology , categorical perception , categorical variable , facial expression , categorization , cognitive psychology , perception , face perception , developmental psychology , event related potential , electroencephalography , audiology , communication , speech perception , neuroscience , artificial intelligence , mathematics , medicine , statistics , computer science
Categorical perception, demonstrated as reduced discrimination of within‐category relative to between‐category differences in stimuli, has been found in a variety of perceptual domains in adults. To examine the development of categorical perception in the domain of facial expression processing, we used behavioral and event‐related potential (ERP) methods to assess discrimination of within‐category (happy‐happy) and between‐category (happy‐sad) differences in facial expressions in 7‐month‐old infants. Data from a visual paired‐comparison test and recordings of attention‐sensitive ERPs showed no discrimination of facial expressions in the within‐category condition, whereas reliable discrimination was observed in the between‐category condition. The results also showed that face‐sensitive ERPs over occipital‐temporal scalp (P400) were attenuated in the within‐category condition relative to the between‐category condition, suggesting a potential neural basis for the reduced within‐category sensitivity. Together, these results suggest that the neural systems underlying categorical representation of facial expressions emerge during the early stages of postnatal development, before acquisition of language.