title: Additivity of Feature-Based and Symmetry-Based Grouping Effects in Multiple Object Tracking.
abstract: Multiple object tracking (MOT) is an attentional process wherein people track several moving targets among several distractors. Symmetry, an important indicator of regularity, is a general spatial pattern observed in natural and artificial scenes. According to the "laws of perceptual organization" proposed by Gestalt psychologists, regularity is a principle of perceptual grouping, such as similarity and closure. A great deal of research reported that feature-based similarity grouping (e.g., grouping based on color, size, or shape) among targets in MOT tasks can improve tracking performance. However, no additive feature-based grouping effects have been reported where the tracking objects had two or more features. "Additive effect" refers to a greater grouping effect produced by grouping based on multiple cues instead of one cue. Can spatial symmetry produce a similar grouping effect similar to that of feature similarity in MOT tasks? Are the grouping effects based on symmetry and feature similarity additive? This study includes four experiments to address these questions. The results of Experiments 1 and 2 demonstrated the automatic symmetry-based grouping effects. More importantly, an additive grouping effect of symmetry and feature similarity was observed in Experiments 3 and 4. Our findings indicate that symmetry can produce an enhanced grouping effect in MOT and facilitate the grouping effect based on color or shape similarity. The "where" and "what" pathways might have played an important role in the additive grouping effect.
authors.affiliation: Beijing Key Lab of Applied Experimental Psychology, School of Psychology, Beijing Normal University Beijing, China.
authors.forename: Chundi
authors.initials: C
authors.lastname: Wang
authors.affiliation: Beijing Key Lab of Applied Experimental Psychology, School of Psychology, Beijing Normal UniversityBeijing, China; State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal UniversityBeijing, China; Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal UniversityBeijing, China.
authors.forename: Xuemin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Psychology, RenMin University of China Beijing, China.
authors.forename: Yongna
authors.initials: Y
authors.lastname: Li
authors.affiliation: Beijing Key Lab of Applied Experimental Psychology, School of Psychology, Beijing Normal University Beijing, China.
authors.forename: Chuang
authors.initials: C
authors.lastname: Lyu
keywords: additivity; feature-based tracking; grouping; multiple object tracking; spatial-motion-based symmetry