Effects of haptic guidance and disturbance on motor learning: Potential advantage of haptic disturbance

One of the primary goals of haptic guidance is to facilitate the learning of complex human motor skills by providing haptic cues that are helpful to induce desired movements. Nevertheless, a majority of previous studies have found that haptic guidance is ineffective, or sometimes even detrimental, to motor skill learning. In this paper, we propose the opposite concept, haptic disturbance, and evaluate its efficacy. In haptic disturbance, haptic cues that interfere with the movements of a learner are presented during training. We designed two methods of haptic disturbance using repulsive and noise-like forces, respectively. The effects of these methods were experimentally assessed, comparatively with the conventional methods of visual learning only and progressive haptic guidance. The motor task was to track a dot moving on a 2D plane with a haptic interface operated with one arm. We found that during training, the progressive haptic guidance showed the best tracking accuracy, but in immediate and delayed retention tests, the noise-like haptic disturbance led to the best performance. The results suggest high potentials for haptic disturbance to be a general strategy for expediting the motor learning process.