Department of Psychology, York University, Toronto, Ontario M3J 1P3, Canada; Vision: Science to Applications (VISTA) Program, York University, Toronto, Ontario M3J 1P3, Canada; Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Department of Psychology, University of Western Ontario, London, Ontario N6A 3K7, Canada; Brain and Mind Institute, University of Western Ontario, London, Ontario N6A 3K7, Canada; Neuroscience Program, University of Western Ontario, London, Ontario N6A 3K7, Canada.
J Exp Child Psychol. 2019 Mar;179:56-72. doi: 10.1016/j.jecp.2018.11.004. Epub 2018 Nov 23.
Vision for action and vision for perception both rely on shape representations derived within the visual system. Whether the same psychological and neural mechanisms underlie both forms of behavior remains hotly contested, and whether this arrangement is equivalent in adults and children is controversial as well. To address these outstanding questions, we used an established psychophysical heuristic, Weber's law, which, in adults, has typically been observed for perceptual judgment tasks but not for actions such as grasping. We examined whether this perception-action dissociation in Weber's law was present in childhood as it is in adulthood and whether it was modulated by stimulus complexity. Two major results emerged. First, although adults evinced visuomotor behavior that violated Weber's law, young children (4.5-6.5 years) adhered to Weber's law when they grasped complex objects ("Efron" blocks), which varied along both the graspable and non-graspable dimensions to maintain a constant surface area, but not when they grasped simple objects, which varied only along the graspable dimension. Second, adherence to Weber's law was found across all ages in the context of a perceptual task. Together, these findings suggest that, in early childhood, visuomotor representations are modulated by perceptual representations, particularly when a refined description of object shape is needed.
行动愿景和感知愿景都依赖于视觉系统内部得出的形状表示。这两种形式的行为是否基于相同的心理和神经机制仍然存在激烈争议，这种安排在成人和儿童中是否等效也存在争议。为了解决这些悬而未决的问题，我们使用了一种既定的心理物理学启发式方法，即韦伯定律，该定律在成人中通常用于感知判断任务，但不适用于抓握等动作。我们研究了这种韦伯定律中的感知-动作分离在儿童期是否与成人一样存在，以及它是否受到刺激复杂性的调节。主要有两个结果。首先，尽管成年人表现出违反韦伯定律的运动行为，但年幼的儿童（4.5-6.5 岁）在抓握复杂物体（“Efron”块）时遵守了韦伯定律，这些物体沿着可抓握和不可抓握的维度变化以保持恒定的表面积，但在抓握简单物体时则不遵守，简单物体仅沿着可抓握的维度变化。其次，在感知任务的背景下，所有年龄段的儿童都遵守了韦伯定律。这些发现表明，在儿童早期，运动视觉代表受到感知代表的调节，特别是在需要对物体形状进行精细描述时。
