UC Santa Cruz

The perception and understanding of human behavior is fundamental for social interaction. Mostly grounded in the theory of embodied cognition, the study of intentional action has focused on different aspects such as action planning and execution, action identity, and action prediction. Based on principles of dynamical systems theory (DST), the goal of this study is to test the method of using eye tracking to expand our knowledge of the temporal dynamics of human intention perception by investigating the time-locked sequence of eye movements during social interaction to investigate the online decision making process during an action observation task. Stimuli consist of 5 sec videos portraying reach and grasp actions, which are either intentional (pour coffee) or unintentional (coffee spills), cooperative action (serve other) or non-cooperative (serve self). In condition 1 participants are asked to determine whether an action presented is intentional, condition 2 whether the action is cooperative while collecting eye tracking data. This study hypothesized that participants' eye movements will be sensitive to the task demands, predicting that (H1) participants in the intentional group will be more likely to attend to the object interactions as compared to the cooperative condition and (H2) participants in the cooperative group will be more likely to attend to social cues between the agents as compared to the intentional condition. The results show that the intentional group was more likely to focus on the object interactions in support of hypothesis 1. Furthermore, results also showed that the cooperative group focused more on social cues in support of hypothesis 2. Therefore, the results of this study strongly support the theory that cognitive processes such as decision-making during an intentional or cooperative action are emergent and the temporal dynamics can be made visible through eye tracking. In support of the dynamical systems theory, external influences such as task demand were shown to have an effect on the viewing pattern, duration of fixations, as well as attention to target details while observing a dynamic, natural and social interaction.