In this project the Principal Investigator will use a combined experimental and theoretical approach to understand the role of risk-sensitivity in movement adaptation. Movements will be analyzed within a decision-theoretic framework. The central hypothesis is that risk-sensitivity is a fundamental determinant of movement adaptation. Young and older adults will perform whole-body movement tasks that involve adaptation to novel reaching dynamics under increasing conditions of risk. Risk will be modulated by altering the subjective value associated with a given movement error. Risk-sensitivity will be quantified based on the relationship between movement error and movement-to-movement adaptation. Older adults are an ideal population to test model predictions because the subjective value of an error is greater. They have a reduced capacity to produce rapid corrections when an error elicits an unwanted action and have a greater prevalence of injurious falls. Together, these studies will determine whether risk-sensitivity provides a mechanistic explanation for the effect of the subjective value of movement error on adaptation.
In terms of broader impacts, this research will test the idea that risk influences movement adaptation. It articulates a conceptual framework that could potentially transform current analyses of the decision-making processes underlying movement adaptation. The proposed work will develop a decision-theoretic, risk-sensitive model of movement adaptation that can be broadly used in the field of motor control to investigate learning in a range of movements and movement contexts, to inform studies on the generalization of risk-sensitive behavior to non-motor tasks, and how this behavior changes across the lifespan. It can inspire future studies that leverage risk-sensitivity to facilitate adaptation, and significantly advance the state-of-the-art in the areas of sensorimotor control, rehabilitation, and decision making.