Emotional speech prosody perception in the first year of life

Abstract

Prosodic aspects of speech are considered more salient than linguistic features in prenatal listening environment. The literature on early prosodic speech perception has been largely focused on the role of infant-directed speech in language development. While emotional prosody is also ubiquitous and contains diverse social cues, its perceptual development trajectory remains unclear. The current study adopted the central fixation paradigm to investigate 3- to 12-month-old infants' preferential listening attention to English monosyllabic words spoken in neutral, happy, angry, and sad tones. Forty-six infants completed the experiment and were assigned to younger and older groups with the median cut-off age of 8 months. Linear mixed-effect model results revealed a prevailing trend of shorter listening time for the sad tone. Furthermore, this reduced level of attention was only statistically significant in the younger infants but not the older group, suggesting that the lower-pitched and longer sad prosody was least attractive to the younger infants. With more exposure to emotional speech and the ongoing neural commitment towards language-specific speech perception in the older infants, the early differential interests in voice emotions showed signs of mitigation in the context of spoken words, leading to a relative increase in their listening time to the sad tone.