Haptic assistance impairs learning: Errors are favorable for learning


While it is generally accepted that experiencing errors during practice can facilitate motor learning, there is much attention on the development of devices such as rehabilitation robots and virtual reality surgical trainers that physically guide the learner through errorless practice. Our purpose was to examine the effect of error during learning on retention and transfer of a skill learned with haptic guidance. Participants learned a tracing task using a Geomagic Touch, which is a desktop haptic interface that can exert precise forces to the user through its end effector. A target line was displayed on a computer screen and this line was traced with the device's stylus. There were two haptic feedback modes: assistance (pulling the cursor back towards target) and disturbance (pushing the cursor off target). Participants generated the tracing movements as fast as possible, or with a goal time of 25 seconds, resulting in 4 practice groups (assistance/fast; assistance/slow; disturbance/fast; disturbance/slow). Participants practiced for 100 trials. Following this there were immediate (10 minute) and delayed (24 hour) retention tests, and a delayed transfer to a new target. ANOVAs showed significantly more error during practice for the error disturbance and fast conditions. However, during immediate retention, delayed retention and transfer there was more error produced by the group that practiced with haptic assistance compared to haptic disturbance. These findings support the notion that error during practice leads to better learning, and should be considered in the design of haptics- and robot-assisted training protocols.

Acknowledgments: This work was supported by NSERC.