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

•Cooperative and competitive relationships are constructed by chasing scenes.•Objects with cooperative relationship can be perceptually grouped.•Objects when doing competitive chase are not perceptually grouped.•Uncovering social structure is initiated during the perceptual stage.•Visual cognition is integrated with social information at an early stage. 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.