Explanation of the Perceptual Oblique Effect Based on the Fidelity of Oculomotor Control During Saccades
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abstract
2017 IEEE. The oblique effect, observed in both humans and animals, refers to the phenomenon of differential perceptual performance in visual recognition tasks that involve horizontal and vertical, vs. diagonal patterns. Furthermore, differences have been found in the visual cortical organization for the horizontal and vertical vs. diagonal representations. However, why such structural differences leading to functional divergence emerge in the first place is yet to be explained. In this paper, we propose a potential explanation for the oblique effect based on the differences in the sampling of oriented edge inputs along different angles due to the mechanics of eye movement. Our hypothesis is that the oblique effect is mainly due to eye movement along the diagonal directions being less precise than the horizontal and the vertical, which causes the sampling of the angles more variable for the diagonal orientations. This will, in turn, lead to structural changes in the visual cortex, which is known to be sensitive to the natural stimulus statistics. We used our Two-Dimensional Linear Homeomorphic Oculomotor Plant Model to simulate saccadic eye movements and sample visual inputs along the eye movement trajectories. Then, we used a multilayer perceptron (as a simple surrogate of the visual cortex) to test how easy it is to learn to classify the different angles from these samples. We found that our results are consistent with the oblique effect data reported in the experimental literature, thus supporting our hypothesis. We expect our work to shed new light on the role of the motor system in determining perceptual organization and function.
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2017 Joint IEEE International Conference on Development and Learning and Epigenetic Robotics (ICDL-EpiRob)
