Effects of Depth, Distractor Transparency, Chromaticity, and Object type in Feature Search of Transparent Real-World Objects

Abstract

Nguyen et al. (2024) found strong evidence for more efficient orientation searches when semi-transparent, simple objects were in front of distractors, especially when the distractors were more opaque. This study investigates if there is strong evidence for depth effects for orientation search of complex, real-world objects and whether there are differences between orientation search for simple and complex objects. Participants searched for semi-transparent, vertical Hershey bars or Remote controllers amongst horizontal bars. These stimuli were either in front of or behind diagonal bars of 0%, 25%, 50%, 75%, or 100% opacity. Stimuli were also normally colored (chromatic) in Experiment 1 and grayscale in Experiment 2 to investigate whether complex object chromaticity affects orientation search. Search was more efficient when targets were in front of distractor diagonal bars, and there were differences in search efficiency between simple and complex, real-world objects when targets were occluded by distractors. In addition, chromaticity aids search for complex, real-world objects when targets were behind a diagonal of opacity 75% or greater. Overall, when occlusion was present (whether the target is occluded or occludes distractors), search was more efficient when targets were perceived closer to the viewer, and this study additionally yields decisive evidence that orientation search for real-world objects (chromatic or achromatic) yielded larger search slopes than orientation search for simple objects when the target is behind an occluder.