Temperament and the development of inhibited approach.

The early development of inhibited approach was studied through the observation of infants' reaching toward objects. 48 infants were observed longitudinally at 6.5, 10, and 13.5 months as they reached for toys under high- and low-intensity/novelty conditions. It was predicted that if an approach system related to positive affect were in place by 6 months, infants should show relative interindividual stability across age in their latency to approach low-intensity/novelty toys. This latency would also be inversely related to temperamental positive affect, that is, children who smiled and laughed more would reach more quickly. It was also predicted that, if behavioral inhibition to high-intensity/novelty stimuli were developing over this period, relative instability of latency to grasp high-intensity/novelty toys would be found. This latency would also be positively related to temperamental ratings of fearfulness, that is, children who were more fearful, would grasp more slowly. These hypotheses were generally supported, with the exception of the relation between parent-reported fearfulness and latency to approach and grasp. In addition, sex differences in frequency of hesitations were found.