Perceptual Decision Making

Perceptual decision making is the act of choosing one option from a set of alternatives based on available sensory information. This sensory information must be interpreted and translated into behavior. In order to investigate perceptual decision making we utilize various experimental paradigms. For example, in one task subjects decide if a degraded image is a face or a house and then press a button to respond with their choice. In this task, indistinct images of faces and houses have to be inter­preted and translated by the brain into a button press with the subject’s hand.

 

Using behavioral and neurophysiological data from the above decision-making paradigm and other similar paradigms, mathematical models of the assumed underlying cognitive processes responsible for the decisions have been developed. Sequential sampling models are particularly successful in explaining response-time data and accuracy in two-choice reaction-time tasks. A prominent version of sequential sampling models are diffusion models, which assume that decisions are formed by continuously accumulating sensory information until one of the two response criteria is reached (diffusion-to-barrier). Once a boundary is met, the decision process is concluded and a motor response is elicited.

 

Importantly, both behavioral and neurophysiological data from perceptual decision making tasks have been modeled as a diffusion-to-barrier process. This provides a quantitative link between the behavioral and neural aspects observed in perceptual decision making. In ongoing projects, we’re expanding upon our previous work and the work of others to 1) provide causal evidence for a role of the dorsolateral prefrontal cortex in perceptual decision making, 2) try to disentangle motor preparation and decision-related processing, and 3) investigate how task instructions and reward information modulate perceptual decision making, specifically with respect to the diffusion-to-barrier model described above.