Eye of origin information does not always facilitate target search

Abstract

Despite being unconsciously experienced, eye of origin information (Zhaoping, 2008) and an invisible collinear structure (Tseng & Chow, 2013) are both reported to guide attention in visual search. Here we investigated the interaction between the facilitative capacities of ocularity and the impairment from collinearity. Observers searched for a target (tilted gap on a bar) in a 9 × 9 horizontal bars display, except that in one column the bars are vertical (collinear item), and in another column presented to another eye (ocular item). The target could overlap with both, either, or neither visual items. Surprisingly, search performance was worsened when a target overlapped with the ocular item, opposite to Zhaoping’s (2008) finding. To isolate the ocular effect from collinear suppression, we removed the collinear column and adopted a homogeneous display of horizontal bars only with an ocular item that comprises parallel horizontal bars. The worsened search performance persisted when the target overlapped with the ocular item. Our results imply that the effect of ocular information on visual search may be task-dependent, and possibly interacts with perceptual organization of display and relative target size.