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Feb 9 2016

Effort, Reward, and Vigor in Decision Making and Movement Control

MIE Department Seminar

February 9, 2016

11:00 AM - 12:00 PM


1043 ERF


Chicago, IL 60607

Effort, Reward, and Vigor in Decision Making and Movement Control


Alaa A. Ahmed, PhD

Department of Integrative Physiology, University of Colorado, Boulder


Abstract: Decisions depend on the reward at stake and the effort required. However, these same variables influence the vigor of the ensuing movement, suggesting that factors that affect evaluation of action also influence performance of the selected action. In this talk, I will describe a mathematical framework that links decision-making with motor control. Each action has a utility, i.e. cost function, that combines the reward at stake with its effort requirements, both discounted as a hyperbolic function of time. The critical assumption of this model is to represent effort via the metabolic energy expended to produce the movement. This energetic representation describes a parameterization of effort as a function of movement duration, mass of the limb, distance, and force, which we confirmed experimentally in reaching movements. Our main result is to show that a single mathematical formulation of action, a utility describing the goodness of the movement via effort, reward, and time, predicts both the decision that animals make as well as the vigor of the movements that follow. This framework accounts for choices that birds make in walking vs. flying, choices that people make in reaching and force production, and the curious fact that pedestrians walk faster in certain cities. We suggest that decision-making and movement control share a common utility in which the expected rewards and the energetic costs are discounted as a function of time.

Bio: Dr. Alaa Ahmed received a B.Sc. in Mechanical Engineering from the American University in Cairo in 1999 and a Ph.D. in Biomedical Engineering from the University of Michigan at Ann Arbor in 2005. She also holds two M.Sc. degrees in Mechanical and Biomedical Engineering. She spent one year as an NIH post-doctoral fellow at the University of Michigan Medical School. From 2006-2008, she was a Whitaker International Fellow and post-doctoral researcher in sensorimotor control at the University of Cambridge. In 2008, she joined the University of Colorado Boulder as an assistant professor in the Department of Integrative Physiology. Her research program uses a neuroeconomic approach that combines techniques from neuroscience, economics, psychology and engineering to investigate the costs and constraints underlying human sensorimotor decision-making, learning, and control. Dr. Ahmed is the recipient of an NSF CAREER Award and a DARPA Young Faculty Award presented to “rising research stars in junior faculty positions at U.S. academic institutions”. Her work has been featured in Forbes, Wired, Time, PBS, and other national and international media outlets.


Max Berniker

Date posted

Oct 14, 2021

Date updated

Oct 14, 2021