The ability of infants to recognize their mothers as distinct from others was investigated by presenting 6 boys and 6 girls at two age levels (5 weeks and 13 weeks) with the following six sequential stimulus conditions: (1) mother's face (MO); (2) stranger's face (SO); (3) mother's face with stranger's voice (MS); (4) stranger's face with mother's voice (SM); (5) mother's face with mother's voice (MM); and (6) stranger's face with stranger's voice (SS). Infants' responses were videotaped. Dependent measures in each condition were total visual fixation to the adult and length of first fixation to the adult. Both age groups discriminated mothers from stranger in the congruent face-voice conditions (MM and SS) by showing longer first fixations to the stranger. The older group also discriminated mothers from stranger by the same measure in the face-no voice conditions (MO and SO). These result suggest that the original discrimination of mothers is not based on visual recognition alone. The older group discriminated between congruent and incongruent face-voice conditions by showing longer first fixations to the incongruent conditions (MS and SM) indicating that by 13 weeks infants have developed specific face-voice expectations for their mothers. There was more total fixation to all the stimulus conditions with age. (Author/MS)