Integrating sequential arrays in visual short-term memory

Are sequential visual arrays represented as separate images or as a combined image in visual short-term memory (VSTM)? Proponents of the integration account suggest that an image of the first array is gradually formed and integrated with an image of the second to produce a combined representation. This view is evidenced by successful performance in an empty-cell detection task. In this task, on a 4 x 4 square matrix, 7 locations are occupied on a first array, followed by a variable interval, and then by 8 other occupied locations on a second array. Subjects' success in identifying the remaining empty cell has been taken as evidence for integration. In this study, we show that success in this task can be better accounted for by a convert-and-compare process than by an integration process. We conclude that VSTM only supports limited integration across sequential arrays.