Zachary Besler’s MSc Thesis Defence

Title: Assessing the contributions of visual and motor experience to action prediction skill in baseball

Thesis Supervisor: Dr. Nicola Hodges
Committee members: Dr. Romeo Chua, Dr. Sean Müller
Defence Chair: Dr. Tania Lam

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, potentially 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; 9 left-handed). Videos of right-handed (RH) pitches, cut 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 (curveballs and changeups). Compared to hitters, pitchers also showed a trend for higher accuracy in “release-point” conditions, where only postural 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 experience aided predictions. However, there was only partial support for a simulation explanation (based on effector specificity).