PARAFOVEAL IDENTIFICATION ASYMMETRY - INTERACTIVE EFFECTS OF SHAPE AND COLOR

If two adjacent letters project to the parafoveal region of the retina , both accuracy and discriminability measures have revealed that a let ter flanked to its foveal side is identified more accurately than a le tter the same distance from the fovea that is flanked to its periphera l side. This parafoveal identification asymmetry is greater if the let ters are dissimilar in shape than if they are similar. Color and brigh tness were introduced as variables in the present experiments. The ide ntification asymmetry was greatest for dissimilar letters in different (complementary) colors. Although those colors differed also in bright ness, two letters that were achromatic but merely different in brightn ess did not produce an asymmetry interaction with shape. Interletter s eparation was varied between .15 and 1.95 deg, and the pattern of resu lts just described persisted across both distances. The synergistic in teraction of shape relation and color relation in determining the amou nt of identification asymmetry suggests that color and shape affect pe rceptual processing at the same level.