Provine R R, Westerman J A
Child Dev. 1979 Jun;50(2):437-41.
The development of the ability to extend the hand across the body midline to contact a visually presented object was examined in 48 normal, full-term, 9--20-week infants. One of the infant's arms was restrained while the behavior of the contralateral, unrestrained arm was observed. Results indicate that infants can first contact objects placed in front of the ipsilateral shoulder, then at the body midline, and later in front of the contralateral shoulder. Between 9 and 17 weeks, success at contacting objects at the midline progressed from 33% to 93%. During this interval, the success in contacting objects presented in front of the contralateral shoulder increased from 0% to 71%. By 18--20 weeks, all infants contacted objects in all three positions. These findings indicate that visually directed hand extension and reaching skills progress from the ipsilateral to include the bilateral and later the contralateral domains. The results are considered in regard to the development of bilateral coordination and complementarity.
对48名9至20周大的正常足月婴儿进行了研究，以考察他们将手越过身体中线去触碰视觉呈现物体的能力发展情况。在观察对侧未受约束手臂的行为时，婴儿的一只手臂被固定住。结果表明，婴儿首先能够触碰放置在同侧肩部前方的物体，然后是身体中线处的物体，之后是对侧肩部前方的物体。在9至17周之间，触碰身体中线处物体的成功率从33%提高到了93%。在此期间，触碰对侧肩部前方物体的成功率从0%增加到了71%。到18至20周时，所有婴儿都能在所有三个位置触碰物体。这些发现表明，视觉引导的伸手和够物技能从同侧发展到包括双侧，随后是对侧区域。研究结果从双侧协调和互补性发展的角度进行了考量。
