Perceptual decision-making: What do we know, and what do we not know?

© 2017 Elsevier Inc. All rights reserved. Perceptual decisions occur when sensory inputs are converted to discrete categorical variables. The neural and computational mechanisms by which rodents, monkeys, and humans make perceptual decisions have been intensively studied since 1989. Here, we address five questions that continue to raise controversy, summarizing research that has asked (1) how information is integrated to form a categorical choice, (2) what computations are carried out in cortical neurons during perceptual decisions, (3) how perceptual decision-making can be studied using cognitive neuroimaging techniques, (4) how we decide when to draw our decisions to a conclusion, and (5) how perceptual decisions are biased by prior information. Despite considerable progress, these remain key open questions in psychology and the neurosciences.