The Social Grouping Effect In Multiple Object Tracking:Evidence From Contralateral Delav Activity

In addition to spatiotemporal properties and featural properties,human can use social relationship information imbedded in the objects to group targets when tracking simultaneous multiple moving objects.For example,when watching a soccer game,human's grouping of players will not only be based on position and clothing information,but also be affected by social relationship information such as cooperation and competition relationships.It helps observers understand and process the dynamic information when individuals who share a certain social relationship are perceived as a group.However,the mechanism behind social information-based grouping still remains unclear.In the current study,the researcher use high temporal resolution electroencephalogram to explore the process of social information-based grouping.Cooperative and competitive relationships,two relationships which have been considered as the most basic in our social life,are chosen as the focus in this study.Each relationship was reflected through dynamic chasing scenes.Contralateral delay activity(CDA)was adopted as a neural marker to measure the grouping effect.In experiment 1,the researcher displayed the scenes by forward-replaying segments selected from the trajectories when two agents(predators)are performing a cooperative or competitive chase toward the same prey(cooperative or competitive relationship condition).A random motion served as a restricted baseline.The author recorded the brain electrical activity of observers during multiple objects tracking processes in order to examine whether agents with a cooperative or competitive relationship could be perceptually grouped when being traced.Nevertheless,the grouping effect might be caused by physical features of the chasing idividuals.Therefore,backward replays of trajectories were used in experiment 2 to explore this possibility.It was mainly found that:(1)Observers can employ social relationship information to group targets when tracking simultaneous multiple moving objects.(2)Cooperative and competitive relationship information have different effects on the grouping of targets during participants' tracking of multiple moving objects:The cooperative relationship information can affect the grouping more deeply and more easily.On the contrary,competitive relationship information is harder to use,and the grouping process lasts longer in this case.In summary,the visual system can use the social relationship information to group targets when tracking simultaneous multiple moving objects.Moreover,different kinds of relationship information can have diverse impacts on targets grouping during the tracking.