Elevated laughing and smiling is a key characteristic of the Angelman syndrome behavioral phenotype, with cross-sectional studies reporting changes with environment and age. This study compares levels of laughing and smiling in 12 participants across three experimental conditions [full social interaction (with eye contact), social interaction with…

Our study examined stability of self-regulation and affective expression in children with autism or Down syndrome over a 2 year period. A behaviorally anchored rating scale was used to assess a self-regulation factor (attention, adaptability, object orientation, and persistence), negative affect factor (hostility, irritability, and compliance),…