Detecting social cues conveyed by laughter and associations with callous-unemotional traits in early childhood.

Beginning in infancy, laughter promotes positive social interactions. However, laughter can also convey derision. Adults distinguish friendly from derisory laughter, appropriately modulating social behavior based on their perceptions of the laugher's intent. Given the connection between laughter perception and broader social functioning, it is important to understand how this skill develops in young children who are initiating foundational early social bonds. Moreover, children who have difficulties forming and maintaining social bonds-including those with callous-unemotional (CU) traits-may show differences in correctly identifying and responding to laughter. Here, 3-, 4-, and 5-year-old children (N = 150; 50% female) categorized laughter clips that varied in conveying affiliation (i.e., friendly) or dominance (i.e., mean) and reported on whether they wanted to play with the person producing the laughter. Children distinguished between laughter types, were accurate at detecting mean laughter, and showed increasing accuracy across ages 3 to 5 years. Children expressed a preference to play with friendly versus mean laughers, a distinction that sharpened from ages 3 to 5 years. Higher CU traits predicted lower accuracy for identifying mean laughs, with no CU-related difference for friendly laughs, though CU traits were not related to social preference. The findings provide the first evidence of young children's ability to detect and appropriately adjust their behavioral intentions based on different communicative signals conveyed in laughter. Findings also suggest that these abilities may be relevant to young children who have difficulties with interpersonal interactions and social bonding.