Abstract
The internal simulation of observed actions is thought to play a crucial role in the process of recognizing action intentions of others (Jeannerod, 2001). In many situations, performers attempt to manipulate this process in order to deceive another. For example, competitive athletes may try to convince opponents that one action is being performed, while another is actually carried out. It has been shown that the visual system is sensitive to the intentions of deceptive movements, although prediction accuracy is reduced (e.g. Grèzes et al., 2004). Real and deceptive actions typically display a degree of spatiotemporal dissimilarity in terms of motion trajectories and temporal dynamics of the movement kinematics. Currently there is no research that examines how these spatiotemporal dissimilarities influence the discriminability of deceptive movements for novice and expert observers. We addressed this question in the context of handball throws. We motion captured deceptive and non-deceptive throwing movements of novice and elite handball field players and used these to generate realistic 3D avatars. In a perceptual task, we asked novice and expert handball players to judge whether observed throws were either deceptive or non-deceptive. The results show that both groups were highly sensitive to deception in throws. Expert observers were significantly better than novices at discriminating throws from both elite and novice performers. In general, discriminability was directly related to spatiotemporal dissimilarities between deceptive and non-deceptive throws. Elite performers produced deceptive throws that were highly similar to non-deceptive throws, resulting in higher misclassifications by observers. We interpreted these findings in the context of prediction errors resulting from internal simulation of kinematically similar deceptive and non-deceptive throws. The higher sensitivity to deception displayed by experts points towards superior action simulation based on stored motor representations for practiced actions, resulting in fewer prediction errors. Future neurophysiological studies should directly address this interpretation.
Meeting abstract presented at VSS 2016