Abstract
The visual search paradigm has been widely used to study the mechanisms underlying visual attention, and search asymmetry provides a source of insight into preattentive visual features. In the current study, we showed that observers were more efficient in searching for a spatially scrambled (or feet only) upright biological motion target among spatially scrambled (or feet only) inverted distractors than vice versa, suggesting that local biological motion signals can act as a basic preattentive feature for the human visual system. Interestingly, such search asymmetry disappeared when the global configuration in biological motion was kept intact, indicating that the attentional effects arising from biological features (e.g., local motion signals) and global novelty (e.g., inverted human figure) could interact and modulate visual search. Our findings provide strong evidence for local biological motion processing independent of global configuration, and shed new light on the mechanism of visual search asymmetry.
This research was supported by the Knowledge Innovation Program of Chinese Academy of Sciences (KSCX2-YW-R-248 and 09CX202020), Chinese Ministry of Science and Technology (No. 2007CB512300), and the US National Science Foundation.