The effect of different types of transformations on unimanual circling movements

In order to investigate the effect of different transformations on coordination performance we compared two experiments with identical visual setup. Participants saw two dots circling next to each other on a screen. The right dot was controlled by the participants' movement and had to be coordinated with the left dot (target stimulus). Participants' movements were dissociated from their effects on the screen by means of transformed feedback. When the transformation was a phase shift (experiment 1) the results show that unimanual coordination occurs in reference to perceptual rather than motor space. When the transformation turned a symmetric movement into a parallel movement and vice versa (experiment 2) the results show neither an advantage for effect-based nor motor-related coordination in the transformed condition. Together, the results indicate that movements are coordinated with the environment in terms of their external effects. However, this coordination mode may break down with certain transformations