We examined 7-month-old infants' responses to 6 joy-eliciting episodes. Three episodes included and 3 did not include a major social-interactive component. Confirmatory factor analysis of infants' joy reactions in these episodes revealed that a 2-factor model significantly improved the fit over a single-factor solution. Those 2 factors represented…

This research unites traditionally disparate developmental domains--cognition and locomotion--to examine the classic cognitive issue of the development of inhibition in infancy. In 2 locomotor A-not-B tasks, 13-month-old walking infants inhibited a prepotent response under low task demands (walking on flat ground), but perseverated under increased…

This study investigated the developmental continuity, stability, and organization of infants' behavioral response to mild stress from 1 to 3 months of age. Changes in infant stress reactivity were expected to coincide with a suspected neurobiological shift around the 2nd month. A total of 53 infants and their mothers participated in this study. At…