In this study, 126 children were observed at 6 months, 12 months, and 2 years. During infancy, latencies to reach for novel objects were measured. At 2 years, positive and negative affect, and behavioral approach-inhibition to low- and high-intensity situations were coded, and mothers assessed behavior problems. Confirmatory factor analysis indicated a 3-dimension model of positivity, negativity, and behavioral approach-inhibition. Positivity was related to low- and high-intensity behavioral approach-inhibition, whereas negativity was linked only to low-intensity behavioral approach-inhibition. Shorter 12-month latencies to reach were predictive of low negativity, high positivity, and behavioral approach at 2 years. Positivity and negativity were correlated with externalizing and internalizing behaviors, respectively. Finally, cluster analysis identified an exuberant group high in externalizing and an inhibited group high in internalizing.