Abstract
In daily life, humans interact with multiple objects in complex environments (e.g., fetching a glass from the cupboard, selecting a book on a shelf, etc.). Target selection is biased toward recently attended features, such that reaches are faster and trajectory curvature is reduced when target features (i.e., color) are repeated—a phenomenon referred to as “priming of pop-out”. However, it is unclear how selecting a single target for action is impacted when it is grouped as part of a greater whole. We examined this question using a visually guided reaching task requiring participants to search for uniquely colored target among distractors and reach toward its location. Importantly, targets were Pac-men that were oriented to be either consistent or inconsistent with a global Kanizsa triangle. We found that movement initiation was faster when an illusory figure was present independent of color repetition and this effect increased with successive figure presentations. Additionally, movement duration and reach curvature were reduced when colors were repeated irrespective of configuration, consistent with priming of pop-out. An interaction also emerged for curvature: color switches were less costly when the configuration changed as well. We interpret this as evidence of binding between target color and global structure. To summarize, repeated Kanizsa figure presentations induced an early global priming effect indicated by faster movement initiation, whereas local color feature priming reduced movement duration and curvature, reflecting later focal decision processes. These results demonstrate that global and local attentional mechanisms play distinct roles in target selection for action and impact behavior during different stages of the decision process.
Meeting abstract presented at VSS 2015