Statistical extraction affects visually guided action.
The visual system summarizes average properties of ensembles of similar objects. We demonstrated an adaptation aftereffect of one such property, mean size, suggesting it is encoded along a single visual dimension (Corbett, et al., 2012), in a similar manner as basic stimulus properties like orientation and direction of motion. To further explore the fundamental nature of ensemble encoding, here we mapped the evolution of mean size adaptation over the course of visually guided grasping. Participants adapted to two sets of dots with different mean sizes. After adaptation, two test dots replaced the adapting sets. Participantsfirstreached to one of these dots, andthenjudged whether it was larger or smaller than the opposite dot. Grip apertures were inversely dependent on theaveragedot size of the preceding adapting patch during the early phase of movements, and this aftereffect dissipated as reaches neared the target. Interestingly, perceptual judgments still showed a marked aftereffect, even though they were made after grasping was completed more-or-less veridically. This effect of mean size adaptation on early visually guided kinematics provides novel evidence that mean size is encoded fundamentally in both perception and action domains, and suggests that ensemble statistics not only influence our perceptions of individual objects but can also affect our physical interactions with the external environment.
University of Trento, Center for Mind/Brain Sciences ; Brown University, Department of Cognitive, Linguistic, and Psychological Sciences.
Jennifer E
JE
Corbett
Brown University, Department of Cognitive, Linguistic, and Psychological Sciences ; Brown University, Institute for Brain Science.
Joo-Hyun
JH
Song
Adaptation aftereffect; Ensemble statistics; Mean size; Visually guided action