Eliminating interlimb transfer asymmetry through exposure

Abstract

This study investigated the asymmetry of interlimb transfer in motor skill learning and explored a method to eliminate it. Two experiments were conducted using a laser pistol shooting task. In Experiment 1, we examined whether interlimb transfer asymmetry occurs in pistol shooting. Right-handed participants trained with either their dominant or nondominant hand. Pre- and post-tests were conducted with both hands. Results showed that shooting performance transferred from the dominant to the nondominant hand immediately after training, but not in the reverse direction. Experiment 2 tested whether the training-plus-exposure (TPE) paradigm could eliminate this asymmetry. Three groups trained with their nondominant hand. Following training, two exposure groups engaged the dominant hand in either a mouse-tracking or keyboard-typing task, while a third group rested. Only the tracking exposure group exhibited complete transfer of shooting skill to the dominant hand. A control group that performed only the tracking task without prior training showed no performance gain. These findings suggest that interlimb transfer in shooting is asymmetric not because of unequal learning, but due to execution-level inhibition that prevents expression of acquired skill. Exposure to a task with similar control demands reactivates access to shared motor representations. This challenges existing models of interlimb transfer focused on learning or storage limitations and supports a new framework that dissociates acquisition from expression. The results also parallel findings from perceptual learning and may inform interventions in sports training and motor rehabilitation.