Abstract
The introduction of non-targets objects into a workspace leads to temporal and spatial adjustments of reaching trajectories towards targets. This is because target and distractor compete for attention during action planning. There have been several investigations into how this competition can be modulated by manipulating features of the distractor that are directly relevant for the movement, like size and orientation. On the contrary, little is known about the influence of features, like target-distractor similarity, that are irrelevant for the execution of the movement. In eye movement studies the similarity of distractors has been revealed to influence oculomotor competition. Because of the tight neural and behavioral coupling between the gaze and reaching system, our aim was to determine the contribution of target-distractor similarity to avoidance movements of the hand. We performed two experiments in which participants had to reach to grasp a target object while a distractor was present in the workspace. Experiment 1 featured a single target location, whereas Experiment 2 featured two target locations. The distractor could be either similar or dissimilar in color to the target. Moreover, the distractor was placed in several possible locations relative to the reaching hand. Kinematic parameters were extracted for analysis from the recorded hand trajectories. The results of both experiments indicate that dissimilar target-distractor pairs have a stronger effect on reaching-to-grasp movements than similar target-distractor pairs. This effect was most pronounced when the distractor was on the outside of the reaching hand. We propose that participants attended more to this specific location, or ‘danger zone’, as collision of the hand with the obstacle is more likely here, and that competition between target and distractor was enhanced. We conclude that target-distractor similarity, a feature not directly relevant for movement planning, can affect hand movements trough increased attentional capture by the distractor.
Meeting abstract presented at VSS 2013