Name: Julie Harrison

Master’s Thesis Defense Meeting
Date: Friday, December 17th, 2021
Time: 10:30 AM
Location: https://bluejeans.com/879822501  
 
Advisor:
Jamie Gorman, Ph.D. (Georgia Tech)
 

Thesis Committee Members: 

Jamie Gorman, Ph.D. (Georgia Tech)
Bruce Walker, Ph.D. (Georgia Tech) 

Christopher Wiese, Ph.D. (Georgia Tech) 

Title: Characteristic Lag and the Intermanual Speed Advantage 

Abstract:  Previous research has found evidence for the intermanual speed advantage, wherein novice actors perform a visually-guided, two-handed task faster with one hand from each member of a dyad (i.e., intermanually) compared to when one actor completes the task with their own two hands (i.e., bimanually). The intermanual speed advantage is reversed or erased, however, after the task has been well-practiced by both actors bimanually. Furthermore, visuomotor coupling (i.e., coupling between eye and hand movements) has been found to underlie the presence of the intermanual speed advantage in novices and its erasure in experienced actors. This is due to a reduced reliance on visual input as the execution of the manual task becomes more fluent. Using secondary data, the present study seeks to further investigate how visuomotor coupling changes as a function of previous bimanual practice. This is done through a characteristic lag analysis, a dynamical systems metric that assesses how close in time and space the gaze and hands are while actors complete a simulated laparoscopic cutting task. Results suggest that the individual visuomotor coordination of the component actors impacts the execution of the task by the dyad in the intermanual condition, and that this change in coordination depends on previous bimanual practice. Specifically, findings show that the lag between the gaze and the hands of novice actors entrains to the partner with the longer lag (i.e., the less coupled partner) when acting in the intermanual trials. However, in experienced actors with previous bimanual practice, the dyad entrains to the actor with the shorter lag (i.e., the more coupled partner) imposing a ceiling on the dyad in intermanual trails and preventing them from decoupling further. This pattern of results demonstrates how changes in visuomotor coupling lag help account for the erasure of the intermanual speed advantage after previous bimanual practice.