Luria Roy, Vogel Edward K
Tel-Aviv University.
J Cogn Neurosci. 2014 Aug;26(8):1819-28. doi: 10.1162/jocn_a_00584. Epub 2014 Feb 24.
The objects around us constantly move and interact, and the perceptual system needs to monitor on-line these interactions and to update the object's status accordingly. Gestalt grouping principles, such as proximity and common fate, play a fundamental role in how we perceive and group these objects. Here, we investigated situations in which the initial object representation as a separate item was updated by a subsequent Gestalt grouping cue (i.e., proximity or common fate). We used a version of the color change detection paradigm, in which the objects started to move separately, then met and stayed stationary, or moved separately, met, and then continued to move together. We monitored the object representations on-line using the contralateral delay activity (CDA; an ERP component indicative of the number of maintained objects), during their movement, and after the objects disappeared and became working memory representations. The results demonstrated that the objects' representations (as indicated by the CDA amplitude) persisted as being separate, even after a Gestalt proximity cue (when the objects "met" and remained stationary on the same position). Only a strong common fate Gestalt cue (when the objects not just met but also moved together) was able to override the objects' initial separate status, creating an integrated representation. These results challenge the view that Gestalt principles cause reflexive grouping. Instead, the object initial representation plays an important role that can override even powerful grouping cues.
我们周围的物体不断移动并相互作用，感知系统需要实时监测这些相互作用，并据此更新物体的状态。格式塔分组原则，如接近性和共同命运原则，在我们如何感知和分组这些物体方面起着根本性的作用。在这里，我们研究了初始物体作为一个单独项目的表征如何被随后的格式塔分组线索（即接近性或共同命运）更新的情况。我们使用了颜色变化检测范式的一个版本，其中物体开始单独移动，然后相遇并静止不动，或者单独移动、相遇，然后继续一起移动。在物体移动期间以及物体消失并成为工作记忆表征之后，我们使用对侧延迟活动（CDA；一种指示所维持物体数量的ERP成分）实时监测物体表征。结果表明，即使在格式塔接近线索出现后（当物体“相遇”并在同一位置保持静止时），物体的表征（由CDA幅度指示）仍保持为分开的状态。只有强烈的共同命运格式塔线索（当物体不仅相遇而且一起移动时）才能推翻物体最初的分开状态，形成一个整合的表征。这些结果挑战了格式塔原则导致反射性分组的观点。相反，物体的初始表征起着重要作用，甚至可以推翻强大分组线索的影响。
