Movement vigor as a traitlike attribute of individuality
Abstract
A common aspect of individuality is our subjective preferences in evaluation of reward and effort. The neural circuits that evaluate these commodities influence circuits that control our movements, raising the possibility that vigor differences between individuals may also be a trait of individuality, reflecting a willingness to expend effort. In contrast, classic theories in motor control suggest that vigor differences reflect a speed-accuracy trade-off, predicting that those who move fast are sacrificing accuracy for speed. Here we tested these contrasting hypotheses. We measured motion of the eyes, head, and arm in healthy humans during various elementary movements (saccades, head-free gaze shifts, and reaching). For each person we characterized their vigor, i.e., the speed with which they moved a body part (peak velocity) with respect to the population mean. Some moved with low vigor, while others moved with high vigor. Those with high vigor tended to react sooner to a visual stimulus, moving both their eyes and arm with a shorter reaction time. Arm and head vigor were tightly linked: individuals who moved their head with high vigor also moved their arm with high vigor. However, eye vigor did not correspond strongly with arm or head vigor. In all modalities, vigor had no impact on end-point accuracy, demonstrating that differences in vigor were not due to a speed-accuracy trade-off. Our results suggest that movement vigor may be a trait of individuality, not reflecting a willingness to accept inaccuracy but demonstrating a propensity to expend effort.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 01, 2018
- Source ID
- 10.1152/jn.00033.2018
Entities
People
- David J Herzfeld
- Ehsan Sedaghat-Nejad
- Ioannis Rigas
- Oleg Komogortsev
- Reza Shadmehr
- Thomas R Reppert
Organizations
- Division of Computer and Network Systems
- Johns Hopkins School of Medicine
- Michigan State University
- National Institute of Neurological Disorders and Stroke
- National Institute of Standards and Technology
- Office of Naval Research
- Texas State University