Jovanovic Bianca, Schwarzer Gudrun
Department of Developmental Psychology, University of Giessen, Germany.
Department of Developmental Psychology, University of Giessen, Germany.
J Exp Child Psychol. 2017 Jan;153:74-82. doi: 10.1016/j.jecp.2016.09.002. Epub 2016 Oct 6.
One effect that illustrates how people adjust aspects of their grasping according to situational constraints is the grasp height effect; when reaching for objects positioned at different heights, adults' grasp height (vertical position of the hand on the object) tends to correlate negatively with object height. This indicates that grasp positions are planned so that they facilitate later placements of the object. The current study investigated the development of the grasp height effect with 3-year-old children, 5-year-old children, and adults. This paradigm allows for studying efficient action planning in the context of a simple task with relatively low motor requirements. Other tasks used so far for studying this issue involved relatively complex adjustments of hand position that younger children might have found difficult to perform. Usually, preschoolers' performance on these tasks was relatively low. We expected that, due to the lower motor requirements of the grasp height paradigm, clearer evidence of efficient planning might be found in preschool children. A second focus of this study was to explore children's behavior in different movement phases of the grasping task. Whereas the task of placing an object at different heights involves planning, putting the object back to its original position seems to depend on recall. The results indicate a significant grasp height effect in all age groups but also significant development across the studied age range. Regarding the second movement phase, when participants were required to put the objects back on the original home shelf, 3- and 5-year-olds did not seem to act based on recall in this context.
一个能说明人们如何根据情境限制来调整抓握动作各方面的效应是抓握高度效应；当伸手去拿处于不同高度的物体时，成年人的抓握高度（手在物体上的垂直位置）往往与物体高度呈负相关。这表明抓握位置的规划是为了便于后续放置物体。本研究调查了3岁儿童、5岁儿童和成年人抓握高度效应的发展情况。这种范式能够在一项运动要求相对较低的简单任务背景下研究高效的动作规划。迄今为止用于研究这个问题的其他任务涉及手部位置的相对复杂调整，年幼的儿童可能会觉得难以完成。通常，学龄前儿童在这些任务上的表现相对较差。我们预计，由于抓握高度范式的运动要求较低，在学龄前儿童中可能会发现更清晰的高效规划证据。本研究的第二个重点是探索儿童在抓握任务不同运动阶段的行为。虽然将物体放置在不同高度的任务涉及规划，但将物体放回其原始位置似乎依赖于记忆。结果表明，所有年龄组都存在显著的抓握高度效应，而且在所研究的年龄范围内也有显著发展。关于第二个运动阶段，当要求参与者将物体放回原来的置物架时，3岁和5岁的儿童在这种情况下似乎不是基于记忆行事。
