生後半年未満の乳児における空間認知2

注視・プレリーチングおよび発声からの分析

抄録

The purposes of this study were (1) to investigate the developmental processes of spatial cognition, motor function and vocalization, and (2) to assess the relation among these processes during development. Three human infants from 10 to 24 weeks of age were longitudinally examined. As a target object was presented within and beyond reach, the infants' visual fixation, prereaching movement and vocalization were analyzed. At 17-18 weeks of age, just after the infants could control their head orientations, the duration of fixation and frequency of prereaching increased gradually only when the target was placed within their reach. Moreover, their hands started to open only to the target within reach. The vocalization tended to accompany prereaching to the target. These results suggested that the acquisition of head control had an important role in adjusting spatial orientation and activating vocalization in early infancy.