Benefits associated with interspersing observation with physical practice trials in motor-related adaptation processes is related to the rest between physical practice trials


Observational practice of a novel visuomotor rotation has not resulted in unintentional (motor) after-effects, despite subsequent benefits when moving in the novel environment. This suggests that observational practice does not update implicit motor planning processes, without previous physical experience. In prior work, we had shown that interspersing physical with observational practice can bring about significant after-effects but observation preceded by a block of physical practice did not. In the current study we compared interspersed and blocked trials of physical and observational practice with a condition where participants rested between trials. We used a mirror-box set-up with virtual targets and feedback rotated 30┬░clockwise. There were 10 participants in 5 groups: physical practice; blocked observation followed by physical practice, or the reverse; interspersed physical and observational practice (every 5 trials); and physical practice with rest every 5 trials. All groups showed after-effects in a post-test, but these were less pronounced for the 2 blocked groups. The interspersing of observation had some direct benefits, in comparison to rest trials, when groups were tested again in the rotated environment. Observation groups also showed increased RTs and greater variability between trials, indicative of strategic adaptation. Any benefits of interspersing observation trials, with respect to updating of the motor system, appeared to be related to consolidation processes associated with the rest between trials. There was no evidence that learning which occurs from observational practice after prior motor experience is qualitatively different from that which occurs from observational practice in the absence of motor experience.

Acknowledgments: The first author would like to acknowledge Discovery grant funding from NSERC (Natural Sciences & Engineering Council of Canada) for this research