APA Dictionary of Psychology

a computational framework in cognitive psychology and neuroscience that explains two-choice decision making in which information, or noisy evidence, is accumulated over time until it reaches one of two decision thresholds, yielding both a choice and a response time. The model is used to break down decision-making behavior into cognitive components, including drift rate (speed and direction of evidence accumulation), decision boundaries or thresholds (evidence required to decide), starting point or bias (initial preference), and nondecision time (processes such as perceptual encoding and motor execution). See also choice axiom; choice reaction time.