Investigation of the motion mimicking ability in healthy subjects during simple and complex tasks

Abstract

From prehistoric humans to modern humans, the motion mimicking ability has persisted through evolution for millions of years. This ability is important for mimicking food-hunting and combat skills of early hominids, and for mimicking sports maneuvers and surgical skills of modern humans. Prior literature has suggested the mimicking ability as having a potential role in post-stroke recovery, which could possibly become an add-on action observation treatment to standard rehabilitation process. However, little is known on how the mimicking ability may be influenced by the difficulty level of the mimicked task. Therefore, this pilot study aimed to investigate the motion mimicking ability of healthy human subjects during simple and complex tasks. One female instructor subject and seven female copier subjects were recruited. The instructor was asked to perform a simple armraising task and a complex bow-arrow task, while the copier was asked to copy the actions of the instructor. Their motions were recorded using a motion capture system for at least three trials per task. We generally found strong correlations between instructor kinematics and copier shoulder kinematics in the sagittal plane for the simple task. Poor correlations were noted for the frontal plane during the complex task, indicating the important role of task complexity in human motion mimicry. We also noted that copiers were relatively more capable of copying the instructor's complex actions in the sagittal plane than in the frontal plane, suggesting that visual perspective of the instructor could be another vital factor in human motion mimicry.