UCL Discovery

Abstract

Drawing portraits upside down is a trick that allows novice artists to reproduce lower-level image features, e.g., contours, while reducing interference from higher-level face cognition. Limiting the available processing time to suffice for lower- but not higher-level operations is a more general way of reducing interference. We elucidate this interference in a novel visual-search task to find a target among distractors. The target had a unique lower-level orientation feature but was identical to distractors in its higher-level object shape. Through bottom-up processes, the unique feature attracted gaze to the target [1-3]. Subsequently, recognizing the attended object as identically shaped as the distractors, viewpoint invariant object recognition [4, 5] interfered. Consequently, gaze often abandoned the target to search elsewhere. If the search stimulus was extinguished at time T after the gaze arrived at the target, reports of target location were more accurate for shorter (T < 500 ms) presentations. This object-to-feature interference, though perhaps unexpected, could underlie common phenomena such as the visual-search asymmetry that finding a familiar letter N among its mirror images is more difficult than the converse [6]. Our results should enable additional examination of known phenomena and interactions between different levels of visual processes.