Abstract: Visual working memory (VWM) performance can benefit from the Gestalt principles of similarity and proximity in the change-detection task. A fundamental issue in this field is how similarity together with proximity influences the VWM representations. One view postulated that the positive effect of similarity on VWM performance was constrained by proximity, such that similarity was effective only when the similar items were near each other in an ordered spatial configuration of memorized items. The other assumed that such effect of similarity could occur regardless of proximity of similar items in a random spatial configuration of memorized items. However, the order of spatial configuration, as a basic organization rule, was not controlled in previous studies of the effect of similarity and proximity in VWM. Such similarity effect might be influenced by the order of spatial configuration for memorized items. Therefore, a crucial test of such fundamental issue is how proximity and the order of spatial configuration influence the similarity effect. We examined how proximity influenced the similarity effect in VWM with the orderliness of spatial configuration of memorized items using a change detection task. Proximity of similar items was manipulated by the distance and the inserted other item between similar items. The proximal condition was the decreased distance between similar items without inserting other item. The non-proximity conditions were the decreased distance between similar items with inserting other item, as well as the increased distance between similar items with or without inserting other item. Furthermore, the present study employed ordered and random spatial configurations of memorized items in experiments 1 and 2, respectively. In Experiment 1, it investigated whether proximity influenced the similarity effect when spatial configuration was in order. Participants were asked to remember 6 colored circles that were located on an imaginary circle (i.e., ordered spatial configuration). In Experiment 2, it aimed to investigate whether proximity influenced the similarity effect when spatial configuration was random. Participants were required to remember 6 colored circles that were presented at random locations around the center of the screen (i.e., random spatial configuration). The hypotheses were that the increased distance and the inserted other item between similar items could impair the similarity effect when spatial configuration of memorized items was in order, and that such proximity could not influence the similarity effect when spatial configuration was random, given the salient cue of similarity in the random spatial configuration. The results showed that the accuracies of similar items were higher than those of dissimilar items in both ordered and random spatial configurations, regardless of proximity of similar items. Furthermore, inserting other item between similar items attenuated the similarity effect when the similar items were far from each other for the ordered spatial configuration, but not for the random spatial configuration. These results suggested that similarity could facilitate VWM performance regardless of the order of spatial configuration for memorized items. Such similarity effect on VWM performance was constrained by proximity only when the spatial configuration of memorized items was in order.

Key words: Visual Working Memory, Spatial Configuration, Similarity, Proximity

摘要： 相似性对视觉工作记忆表征的促进被称为相似性效应。以相似项目间的距离和是否插入其他项目改变邻近性，并操纵记忆项空间构型有序性，探讨邻近性对相似性效应的影响。结果发现，不同空间构型和邻近性条件下相似项目的记忆正确率高于非相似项目；在空间构型有序下，相似项目距离远时，插入其他项目时的相似性效应值低于不插入，而空间构型无序下未发现显著差异。这表明相似性促进视觉工作记忆表征，空间构型在邻近性对相似性效应的影响中起重要作用。

关键词: 视觉工作记忆, 空间构型, 相似性, 邻近性