The Role Of Social Information In Perceptual Organization

Though visual scenes in front of our eyes are consisted of discrete elements, they are constrained by coherent structures in the meantime. Hence, to understand the visual world in a meaningful way, visual system is not only to perceive the objects individually, but also to uncover its underlying structures and organize the discrete objects into groups accordingly. Besides, this capacity of organization plays an important role when human beings interact with physical world and social scenes. Previous studies have found that the organization process emerges from perceptual experience and creates perceptual groupings of discrete elements according to certain principles. For the discrete elements, though it is possible that the processing could produce different perceptual experiences, in fact the visual perception is inclined to form the most coherent and reasonable representations in specific situations. Thus, it is necessary to find what principles or properties of stimuli determine the perceptual grouping. At present, this issue has been studied by ample of researchers. However, so far only the physical aspects of this process have been emphasized, finding several grouping principles concerning purely physical relationships for the elements, and it is still unclear whether the social relationship information imbedded in the objects can also be involved in perceptual grouping. Nevertheless, our human acts on social structures which are shaped by the social relationship, and accordingly one’s behaviors are always affected by the people around. Hence, it will help us understand the actual meanings of social behaviors if the individuals with certain social relationship are perceived as a group. Therefore, I hypothesized that the vision can also use the social relationship information to perceptually group objects.In the current study, the cooperative and competitive relationships which have been considered as two basic relationships in our social world are focused on. Each relationship is transmitted by hand gestures or dynamic chasing scenes. Here, I measured the grouping effect in terms of its induced attentional consequences via behavioral paradigms and ERPs (event-related potentials) technique. The experiments are divided into three parts. The experiments in the first parts are to explore whether the cooperative objects appeared in the directly interactive scene will be perceived as a group. This cooperative condition was constructed in accordance with the handshake gesture, while the control conditions were containing the hand gestures but without interactive meaning. To investigate the grouping effect, the attentional distributions on varied conditions were compared when participants completed the cue task or the distraction task. In the second part, the author explored whether the objects with competitive relationship in the directly interactive scene will be organized into a whole group at the perceptual stage. To investigate this issue, the author presented the competitive relationship by simulating boxing-match with two fists, and used the same paradigms as the experiments in the first part. In the third part, the cooperative and competitive relationships from indirect interaction were involved, which were transmitted in dynamic chasing scenes wherein two agents (predators) cooperatively or competitively chasing a common target. Here, the author mainly used the cue task to measure the attentional distributions on different conditions, and accordingly inferred which social relationship could act as a factor to drive perceptual grouping. Finally, it was mainly found that:(1) The interactive scene and social relationship information have different influences on the perceptual grouping. Specifically, with the direct interaction-handshake or boxing-match, the objects with cooperative and competitive relationship are both perceptually grouped; while with the indirect interaction-dynamic chasing, only the cooperative objects are perceptually grouped, but the competitive relationship has no effect on perceptual grouping.(2) Except for the explanation of the influence of social information, these results can’t be interpreted by the other possibilities, including the physical cues of perceptual grouping, emotion, physical fit, perceptual familiarity, and so on.(3) The impact of social information truly occurs at the perceptual stage (about200ms after onset), with an automatically and irresistible way. In summary, the visual system can use the social relationship information to perceptually group discrete objects. It implies that social information can become involved in visual cognition at an early perceptual stage.