Comments on Thelen and Ulrich's monograph in this issue. Examines theoretical and empirical sections and findings, concluding that the authors have taken a major step forward by introducing the dynamic systems perspective to the study of behavioral coordination in infants, thus opening the way for experimental investigation of phenomena that could…

Examined how infants acquire adaptive locomotion in the novel task of going up and down slopes. Found that infants' judgments became increasingly accurate and exploration became increasingly efficient, with no transfer over the transition from crawling to walking. Infants learned to gauge their abilities on-line as they encountered each hill at…

Two longitudinal studies examined social-cognitive skill emergence in 9- to 15-month olds, mother-infant interaction regarding joint attentional engagement, and infant's communicative competence. Findings indicated a reliable pattern of social-cognitive skill emergence and that amount of time spent in joint engagement with mothers and mothers' use…

Studied the ontogeny of walking by prelocomotor infants. Results support a dynamic systems view of development and the view that upright locomotion emerges from the self-organization of multiple cooperating elements rather than as a result of a preexisting neural code. (Author/GR)