Yurkovic-Harding Julia, Bradshaw Jessica
Department of Psychology, University of South Carolina, Columbia, South Carolina, USA.
Carolina Autism and Neurodevelopment Research Center, University of South Carolina, Columbia, South Carolina, USA.
Infancy. 2025 Jan-Feb;30(1):e12646. doi: 10.1111/infa.12646.
Social smiling is the earliest gained social communication skill, emerging around 2 months of age. From 2 to 6-months, infants primarily smile in response to caregivers. After 6 months, infants coordinate social smiles with other social cues to initiate interactions with the caregiver. Social smiling is reduced in older infants with autism spectrum disorder (ASD) but has rarely been studied before 6 months of life. The current study therefore aimed to understand the component parts of infant social smiles, namely look to caregiver and smile, during face-to-face interactions in 3 and 4-month-old infants at elevated (EL) and low likelihood (LL) for ASD. We found that EL and LL infants looked to their caregiver and smiled for similar amounts of time and at similar rates, suggesting that social smiling manifests similarly in both groups. A nuanced difference between groups emerged when considering temporal dynamics of looking and smiling. Specifically, 3-month-old EL infants demonstrated extended looking to the caregiver after smile offset. These findings suggest that social smiling is largely typical in EL infants in early infancy, with subtle differences in temporal coupling. Future research is needed to understand the full magnitude of these differences and their implications for social development.
社交性微笑是最早获得的社交沟通技能,大约在2个月大时出现。在2至6个月大时,婴儿主要是对照顾者的回应而微笑。6个月后,婴儿会将社交性微笑与其他社交线索协调起来,以发起与照顾者的互动。患有自闭症谱系障碍(ASD)的大龄婴儿的社交性微笑会减少,但在6个月大之前很少有相关研究。因此,本研究旨在了解3个月和4个月大、患ASD可能性高(EL)和低(LL)的婴儿在面对面互动中社交性微笑的组成部分,即看向照顾者和微笑。我们发现,EL组和LL组的婴儿看向照顾者并微笑的时间和频率相似,这表明两组婴儿的社交性微笑表现相似。在考虑看向和微笑的时间动态时,两组之间出现了细微的差异。具体而言,3个月大的EL组婴儿在微笑结束后会延长看向照顾者的时间。这些发现表明,在婴儿早期,EL组婴儿的社交性微笑在很大程度上是正常的,只是在时间耦合上存在细微差异。需要进一步的研究来了解这些差异的全部程度及其对社交发展的影响。