Infants Recognized Other-Race Faces When Learning Them With Incidental Emotional Sounds.

Infant face recognition shows plasticity, with recent evidence indicating enhancement by the presence of emotional facial expressions. The mechanisms and domain-generality of this effect remain largely unknown. This study tested whether auditory emotional cues (vocalizations) facilitated infants' recognition of other-race faces, a perceptual challenge during the first year of life. Infants (N = 89) were presented with emotionally neutral faces paired with happy, sad, or neutral vocal sounds in a within-subjects design. Experiment 1 assessed recognition using identical face images between the familiarization and test phases, while Experiment 2 examined face recognition across viewpoint changes. Across both experiments, infants exhibited successful face recognition only when they were learned with emotional sounds (happy and sad). This facilitative effect remained stable across the tested age range and did not differ between happy and sad vocalizations. Infants' eye movement data revealed comparable face-looking patterns across conditions, suggesting that the facilitation was not driven by changes in visual attention. Thus, incidental, cross-modal emotional signals significantly enhance infant face recognition. This underscores the early integrative nature of emotion processing and its catalytic role in cognitive development.