The effect of perceptual expertise on visual short-term memory

Abstract

Visual short-term memory (VSTM) capacity is larger for faces than other complex objects. Inversion reduces capacity for faces more than nonfaces (Curby and Gauthier, 2007). These findings suggest that VSTM is not influenced simply by object complexity, but also by the encoding processes employed by face experts. Previous research (Scolari, Vogel and Awh, 2008) found that perceptual expertise enhances the resolution but not the number of representations in working memory. In other words, people have a more detailed memory, instead of a larger WM capacity, for faces than nonfaces. Since we are more expert at recognizing own-race than other-race faces, we investigated whether the own-race advantage is due to a higher resolution of own-race face representations. Six study items (Chinese and Caucasian faces as well as shaded cubes) were simultaneously shown on screen on each trial. After a short delay, a single image was presented. Participants were asked to judge whether this image was the same or different from the item that originally appeared in that location. Performance of both cross-category changes (i.e. face to cube, cube to face) and within-category changes (i.e. face to face, cube to cube, color to color) was measured. Neither own-race nor other-race faces showed an inversion effect when stimuli changed between categories. However, an inversion effect was found for both own-race and other-race faces when stimuli changed within a category. These results suggest that both own-race and other-race faces are stored with high resolution in working memory.