Remembering faces and scenes: The mixed-category advantage in visual working memory.

We examined the mixed-category memory advantage for faces and scenes to determine how domain-specific cortical resources constrain visual working memory. Consistent with previous findings, visual working memory for a display of 2 faces and 2 scenes was better than that for a display of 4 faces or 4 scenes. This pattern was unaffected by manipulations of encoding duration. However, the mixed-category advantage was carried solely by faces: Memory for scenes was not better when scenes were encoded with faces rather than with other scenes. The asymmetry between faces and scenes was found when items were presented simultaneously or sequentially, centrally, or peripherally, and when scenes were drawn from a narrow category. A further experiment showed a mixed-category advantage in memory for faces and bodies, but not in memory for scenes and objects. The results suggest that unique category-specific interactions contribute significantly to the mixed-category advantage in visual working memory. (PsycINFO Database Record

Similarity effects in visual working memory.

Perceptual similarity is an important property of multiple stimuli. Its computation supports a wide range of cognitive functions, including reasoning, categorization, and memory recognition. It is important, therefore, to determine why previous research has found conflicting effects of inter-item similarity on visual working memory. Studies reporting a similarity advantage have used simple stimuli whose similarity varied along a featural continuum. Studies reporting a similarity disadvantage have used complex stimuli from either a single or multiple categories. To elucidate stimulus conditions for similarity effects in visual working memory, we tested memory for complex stimuli (faces) whose similarity varied along a morph continuum. Participants encoded 3 morphs generated from a single face identity in the similar condition, or 3 morphs generated from different face identities in the dissimilar condition. After a brief delay, a test face appeared at one of the encoding locations for participants to make a same/different judgment. Two experiments showed that similarity enhanced memory accuracy without changing the response criterion. These findings support previous computational models that incorporate featural variance as a component of working memory load. They delineate limitations of models that emphasize cortical resources or response decisions.