Social grouping: Perceptual grouping of objects by cooperative but not competitive relationships in dynamic chase

Historically, perceptual grouping is associated with physical principles. This article reports a novel finding that social information—cooperative but not competitive relationships—can drive perceptual grouping of objects in dynamic chase. Particularly, each relationship was constructed with human-generated chasing motions (i.e., two predators and one prey), and its role on perceptual grouping was examined by grouping-induced effect—attentional consequences. The results showed that: (1) Predators can be perceived as a group due to their cooperative relationship, causing attention to automatically spread within grouped predators, thus the response to target appearing on uncued predator is also facilitated; and (2) The attentional effect on competitive predators has no difference from any condition which controls low-level motion patterns, even including the random-motion condition wherein no grouping factor was contained. These findings extend perceptualgrouping into the social field, implying that social information gets involved in visual cognition at an early perceptual stage.