Research findings are reviewed concerning infants' abilities to discriminate parents from other social stimuli during the first 6 months of life. The term "discrimination" is used to signify the ability of infants to respond differentially to two or more social stimuli. Studies reviewed are categorized in terms of the visual, auditory,…

A review of research leads to the proposal that infants' perception of "fragile" contrasts is lost due to their lack of exposure to particular sounds. Perception of "robust" contrasts is lost around the onset of formal language training due to children's lack of experience with phonologically irrelevant sounds. (Author/CB)