Adam Barnas, Jessica L. James, Lindsey C. Meter, Jeremy T. Schwob
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In the mirror illusion, visual information from a mirror reflection of one hand influences the perceived location of the other hand. Holmes, Crozier, and Spence (2004) demonstrated this visual capture effect on a spatial localization task in which visual information was found to influence reaching movements toward a target when the seen (in the mirror) and felt (proprioception) position of the hand did not match. Furthermore, past results suggest that visual information about hand position overrides the proprioceptive information when the hands were used to indicate perceived object length. The conflict between vision and proprioceptive information of limb location was further examined in three experiments by means of a task in which participants adjusted the physical distance of their unseen hand in the horizontal plane and sagittal plane during judgments of affordance. In each trial, participants viewed their visible hand and its reflection in a mirror, while their unseen hand was positioned at several positions located behind the mirror. At all times, the visible hand was positioned fifteen centimeters in front of the mirror, and as such, the unseen hand always appeared to be thirty centimeters from the visible hand regardless of its actual position. While viewing their visible hand and its reflection, participants performed simultaneous finger movements with both hands to maximize the visual capture illusion. In Experiments 1 and 2, participants then viewed a series of tubes of varying lengths presented in ascending and descending order and called out the point at which they were no longer able to catch the tube given the current distance between their hands, whether felt or seen. In Experiment 3, participants viewed an object presented at different locations in the sagittal plane and repositioned their unseen hand such that it was underneath the object. Future experiments should examine other action capabilities.
Benjamin R. Kunz
Primary Advisor's Department
Stander Symposium project
"The Role of Visual and Proprioceptive Limb Information in Affordance Judgments and Action Capabilities" (2013). Stander Symposium Projects. 214.