Visual similarity at encoding and retrieval in an item recognition task.

The aim of this experiment was to examine the effects of shape similarity in visual working memory using a six alternative recognition task of Chinese characters. Shape similarity among items was manipulated at both encoding and retrieval in order to assess in which phase similarity impairs recognition to a greater degree. Results revealed that performance is particularly facilitated by high discriminability at retrieval but also by the presence of similar items at encoding, as similarity simplifies the global representation of the display and reduces memory load. Moreover, results provide further evidence that the classical similarity effect can be reversed in the visual domain when item memory (as opposed to order) is assessed.