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Julia Trommershäuser

Department of Psychology, Giessen University, Germany

Wednesday 31 May 2006


Seminar Room B10 (Basement)

Alexandra House, 17 Queen Square, London, WC1N 3AR


 Effects of Sensory and Motor Uncertainty on Movement Planning under Risk

I present research that combines theoretical and experimental methods to investigate visuo-motor strategies during the planning and execution of goal-directed movements under risk. In our experiments, we study human movement planning in environments where there are explicit gains and losses associated with the outcomes of actions and compare human performance to a model of optimal performance based on statistical decision theory. The model comprises approaches of motor control, statistical and Bayesian decision theory and is based on the idea that goal-directed movements reflect a subject’s choice under the constraints of the perceptual and motor system.

I will present several experimental tests of the model. In these experiments, subjects effectively acted so as to maximize gain, in good agreement with predictions of the model. Our experiments further demonstrate that subjects are able to modify their movement strategies to maximize expected gain in response to changes in response variability, reward, penalty, and object locations. Optimal performance can be disrupted by introducing uncertainty to the presentation of reward, penalty or object location.