Thomas E Boggs



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The visual system often misperceives the curvature of arcs. The current study investigated the role the primary visual cortex (V1) and area V4 of the occipital lobe play in arc perception. Past research has demonstrated that the V4 response is responsible for curvature detection and perception. The V4 response is directly proportional to the amount of excitation of V1 simple cells. By manipulating the style of the line that the arc is drawn in (solid, dotted), fewer simple cells in V1 should be excited therefore causing a smaller response in the curvature detectors of V4. Male and female university students, in independent groups, adjusted the size of a circle to match the curvature of the arc in nine different trials of varying arc radius and arc length. Participants saw a solid line arc or a dotted arc. The dotted arc should appear to be less curved than the solid arc due to less excitation from the V1 simple cells. Preliminary results did not indicate a significant main effect of line style (solid, dotted). Preliminary results did indicate a significant effect of length, a significant effect of radius, and a significant radius with line style interaction. The preliminary results agree with past research by suggesting shorter arcs tend to be underestimated more than larger arcs. By determining how the amount of excitation of V1 simple cells are related to veridical curvature detection, we better understand how the brain processes curvature.

Publication Date


Project Designation

Capstone Project - Undergraduate

Primary Advisor

Greg C. Elvers

Primary Advisor's Department



Stander Symposium project

A Biological Perspective: The Effects of Line Style on Arc Curvature Perception