An integrated theory of deciding and acting

How do we translate information from sensory inputs and memory stores into goal-directed actions? In the last 40 years, the fields of cognitive psychology and cognitive neuroscience have focused on the decision-making stage, and very few attempts have been made to understand the complete process. The aim of the present scientific proposal is to elaborate an integrated computational theory of deciding and acting in humans, which explains conflicting measurements from these traditionally separate fields of research, and provides joint, precise quantitative predictions about them. The core hypothesis of the theory is that motor execution is determined by the same evidence accumulation variable that drives decision-making. This hypothesis strongly departs from current models of decision-making that represent motor execution as a residual parameter, under the assumption that motor execution captures effects that are not cognitively interesting. The theory will be tested through a series of experiments that combine cognitive modeling, behavioral and electrophysiological measurements (electromyography of response-relevant muscles and electroencephalography). Specifically, the experiments aim at (i) testing and characterizing the hypothetical dependency of motor execution to the evolving decision variable, (ii) generalizing the theory to a wide range of choice laboratory tasks and different response effectors, (iii) identifying potential boundary conditions of application, and (iv) elucidating the relationship between decision-making, motor execution, and confidence judgments. In a final part of the project, the theory will be applied to developmental data, in order to provide new theoretical insight into the development of decision-making and motor execution across the lifespan. If successful, this work should provide new perspectives into a broader range of research problems, from perception-action coupling to movement disorders that appear to have a cognitive basis.