Event-related potentials (ERPs) were recorded from 6-month-olds as eac
h watched pictures of the mother's face and a stranger's face. The ERP
s differed for the 2 faces, but the pattern of neural activity elicite
d depended on whether the mother and stranger looked different (Experi
ment 1, n = 22) or alike (Experiment 3, n = 22). In contrast, when dif
ferent 6-month-olds were each shown 1 of these 44:pairs of faces their
ERPs did not differ between the 2 faces (Experiment 2, n = 22, and Ex
periment 4, n = 22). In a visual preference test of recognition, infan
ts showed no evidence of recognizing the mother's face (Experiment 5,
n = 32). Together, these results suggest that infants are able to reco
gnize their mothers' faces but (1) the neural processes accompanying r
ecognition depend on the difficulty with which mother can be discrimin
ated from stranger and (2) under the conditions investigated in this s
tudy, ERPs are a more sensitive measure of recognition than is looking
time.