Generalized Motor Program theory (Schmidt 1975) has been the most influential theory of the transfer of motor learning. The theory suggested that a motor program is represented in a temporal structure namely 'relative timing' which is defined by a ratio of the submovement duration to the total movement duration. According to the relative timing model, a motor program can be easily transferred to similar movements, if the relative timing is preserved. This model has problems. The invariance of relative timing is often violated in empirical data, and, more importantly, the relative timing model says nothing about the spatial aspects of the motor programs. In this presentation, we suggest a pyramid model, which is well established in visual perception, to explain the spatial structure of motor program. Due to the self-similar structure of the pyramid model, a motor program should be easily transferred when the ratio between the size (D) and accuracy (A) of movements are preserved. The role of the ratio (D/A) in transfer was tested in eight conditions. The movement and the target size were changed by a factor of two. The eight conditions represented all cases of the target and movement size changes. Results supported pyramid model showing that the transfer was the most efficient when the ratio between the size and the accuracy of movement was preserved. Further analysis of the temporal structure of data showed that the relative timing couldn't explain the results. |