Infants recognized other-race faces when learning them with incidental emotional sounds

Recent research has revealed a facilitative effect of facial emotions on infants' face recognition; however, the underlying mechanisms remain unclear. To investigate the domain-generality of this effect, we examined whether emotional vocalizations enhance infants' recognition of other-race faces, a perceptual challenge during the first year of life. Infants (N = 61, 121– 404 days) 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 (data collected between November 2022 – September 2023), while Experiment 2 examined infants’ face recognition across viewpoint changes (data collected between February – May 2024). 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. Emotion’s facilitative effect may emerge early in development as Bayesian analyses further support this developmental invariance over 4 to 13 months of age. Infants’ eye movement data revealed comparable face looking patterns across emotional conditions, suggesting that the facilitation was not driven by changes in visual attention. These findings demonstrated that emotional signals, even when presented cross-modally and incidentally, can enhance face recognition in infancy. Early emotional processing possesses an integrative nature and is a critical catalyst for cognitive development. The wide selection of audio-visual stimuli ensured the generalizability of the current findings; other constraints on generality and sample demographics were discussed.