Incorporation of a stop signal task does not impair learning of a serial key-press task: Evidence against inhibition-induced forgetting in explicit motor learning


Recent behavioural studies have described an inhibition-induced forgetting effect where, in a motor reaction task using faces as stimuli, a decrease in incidental memory was seen for the faces displayed when the motor response was required to be inhibited (e.g., no-go cues). The purpose of the present study was to investigate this effect on explicit motor learning using a serial key-press task. We hypothesised that participants in a movement inhibition (stop signal) group would show decreased learning compared to groups that did not experience inhibition. Participants (n=46) performed a serial key-press task requiring typing a sequence of digits (2,4,8,6) on the numeric keypad of a computer keyboard in an overall movement time of 900ms and between key-press durations of 22.2%, 44.4%, and 33.4% of the total movement time. Participants in the control group performed four practice blocks of 12 trials during which they were provided with terminal feedback on keypress and timing accuracy. Participants in the "stop signal" group were asked to prepare for every trial (24 trials) but had to attempt to inhibit their movement if a stop signal occurred (50% of trials). A third group involved participants with an additional 12 trials per block where no movement was required. Contrary to the hypothesis, no significant learning differences between groups were found for immediate or delayed retention, or for transfer. These results suggest that inhibition-induced forgetting may be limited to incidental learning, and inhibition effects are overshadowed by explicit learning of a motor skill.

Acknowledgments: Supported by NSERC and the Ontario Ministry of Research and Innovation and Science