Melanie Palomares and Howard Egeth
Johns Hopkins University

Does spatial separation between attended objects affect their recognition? While viewing
letters or gratings, observers determined whether one or two diagonal targets appeared
among non-diagonal distractors (with letters, N, Z among H, I). Though intuition may
predict that objects in one attentional window would be perceived better, we found that
detection of two targets is better at large separations. For letters, accuracy is always
poorest at separations of < 3.9 deg, regardless of whether the targets were same or
different. However for gratings, the effect of inter-target separation depended on whether
targets were the same or different in orientation. Our results support the idea that simple
features such as gratings and complex objects such as letters are detected by different
mechanisms.