Chunking movements into sequence: the visual pre-selection of subsequent goals

The chunking of individual movements into sequences has been studied extensively from a motor point of view. Here we approach the planning of sequential behavior from a perceptual perspective investigating the sensorimotor transformations that accompany visually guided sequential behavior. We show that visual attention pre-selects subsequent goals only if two movements are planned to be carried out in rapid succession and therefore are integrated into one common action. This causes visual attention to select both intended goal locations in advance. In contrast, in more slowly executed motor sequences, the single movements are programmed one-by-one and subsequent movement goals are only later visually prepared ('just in time'). The visual selection of a subsequent goal location crucially depends on the speed of the planned sequence: the longer the inter-reach delay, the less visual attention is deployed to the subsequent goal initially.