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The effects of shape crowding on grasping
Juan Chen1, Sanasi Jayawardena1, Melvyn Alan Goodale1
1The Brain and Mind Institute, the University of Western Ontario, London, Ontario, Canada.
Journal of Vision
|March 12, 2015
Summary
Grasping actions can use invisible shape information, even when crowding impairs perception. This ability to guide actions with unseen shapes depends on hand proficiency.
Area of Science:
- Visual perception
- Motor control
- Cognitive neuroscience
Background:
- Crowding impairs visual identification of peripheral targets.
- Previous research showed grip scaling to target size despite size perception deficits.
- The impact of crowding on grasping based on object shape remained unclear.
Purpose of the Study:
- To investigate if grasping can overcome crowding effects on object shape perception.
- To determine if action proficiency influences the ability to use invisible shape information for grasping.
Main Methods:
- Presenting 3D rectangular blocks in isolation or crowded by peripheral blocks.
- Requiring participants to grasp the target block across its width or estimate its width.
- Comparing grasping performance with the dominant (right) and non-dominant (left) hands.
Main Results:
- Grasping scaled to target width even when width perception was impaired by crowding.
- Left-hand grasping did not overcome crowding effects on shape perception.
- Right-hand grasping demonstrated an ability to utilize invisible shape information.
Conclusions:
- Grasping actions can utilize unseen shape information to guide movements.
- The ability to use invisible shape information for action is dependent on motor proficiency and hand dominance.
