Seeing Where the Stone Is Thrown by Observing a Point-Light Thrower: Perceiving the Effect of Action Is Enabled by Information,Not Motor Experience

People are very adept at perceiving biological motion (e.g., Johansson, 1973 Johansson, G. (1973). Visual perception of biological motion and a model for its analysis. Perception & Psychophysics, 14(2), 201–211.[Crossref], [Web of Science ®] , [Google Scholar]). This ability has been an essential life skill to members of this social species. The human niche during the ice age was socially coordinated hunting for big game. Being able to judge the location targeted by the throw of a conspecific would be a valuable perceptual ability that we now study to investigate 2 competing theories of biological motion perception: Common Coding (CC; Prinz, 1997 Prinz, W. (1997). Perception and action planning. European Journal of Cognitive Psychology, 9(2), 129–154.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) and Kinematic Specification of Dynamics (KSD; Runeson & Frykholm, 1983 Runeson, S., & Frykholm, G. (1983). Kinematic specification of dynamics as an informational bias for person-and-action perception: Expectation, gender recognition, and deceptive intent. Journal of Experimental Psychology: General, 112, 585–615.[Crossref], [Web of Science ®] , [Google Scholar]). The 2 theories diverge in attributing perceptual ability to either motor or visual experience, respectively. To test predictions of the CC theory, we performed 3 experiments to manipulate observers' specific motor experience while they judged the targeted location of throwing by watching point-light displays. In Experiment 1, we tested whether the identity of the thrower in the display mattered. In Experiment 2, we tested whether the motor expertise of the observer mattered. In Experiment 3, we tested whether the gender/style of throwing demonstrated by the point-light thrower mattered. The combined results failed to support CC theory, suggesting that motor experience is not required for the perception of action. Because all participants judged the target location of throwing quite well, KSD theory suggests that the kinematic information available in the displays may have enabled the perception. We performed Experiment 4 to analyze the information. We found that the judgment pattern exhibited by the observers in both Experiments 1 and 2 was well predicted by the KSD theory. Thus, we concluded that the perception of biological motion is enabled by visual information and improved by visual experience.