Abstract
Both visual and motor experiences impact action prediction, yet through potentially different mechanisms. Having physical experience with an action is thought to engage motor simulative processes, activating the watcher's motor system in an effector specific manner, aiding prediction. Leveraging baseball's unique specialization demands, we assessed pitch discrimination in athletes with predominantly visual experience (hitters, n = 41) and motor experience (pitchers, n = 42; 10 = left-handed). Right-handed (RH) pitches, frozen in time at or after ball release, of three different pitches, were used to assess pitch prediction accuracy. Two versions of each video clip were shown; the original RH clips were "flipped" to make the pitcher appear to throw left-handed (LH). Pitchers and hitters had reliable responses and showed high accuracy (~70%) and discriminability. Pitchers were more discriminatory than hitters (d prime) when contrasting two pitch types with the same initial trajectory and speed, but different postural cues (curve-balls and change-ups). Pitchers showed a trend for higher accuracy in 'release-point' conditions, compared to hitters, where only postural cue information was available. Accuracy was high on both left and right videos, but only LH pitchers showed a LH video advantage (although at release point there were effector specific advantages for LH and RH pitchers). Because pitchers did not differ in accuracy from hitters, despite a lack of visual experience, this suggests that their motor experiences are aiding prediction. However, there was only partial support for a simulation explanation (based on effector specificity).Acknowledgments: We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC). Nous remercions le Conseil de recherches en sciences naturelles et en génie du Canada (CRSNG) de son soutien.