Behavioral effects of visual field location on processing motion- and luminance-defined form

Abstract

Traditional theories posit a ventral cortical visual pathway subserving object recognition regardless of the information defining the contour. However, functional magnetic resonance imaging (fMRI) studies have shown dorsal cortical activity during visual processing of static luminance-defined (SL) and motion-defined form (MDF). It is unknown if this activity is supported behaviorally, or if it depends on central or peripheral vision. The present study compared behavioral performance with two types of MDF [one without translational motion (MDF) and another with (TM)] and SL shapes in a shape matching task where shape pairs appeared in the upper or lower visual fields or along the horizontal meridian of central or peripheral vision. MDF matching was superior to the other contour types regardless of location in central vision. Both MDF and TM matching was superior to SL matching for presentations in peripheral vision. Importantly, there was an advantage for MDF and TM matching in the lower peripheral visual field that was not present for SL forms. These results are consistent with previous behavioral findings that show no field advantage for static form processing and a lower field advantage for motion processing. They are also suggestive of more dorsal cortical involvement in the processing of shapes defined by motion than luminance.