How mechanisms of perceptual decision-making affect the psychometric function

► Signal Detection Theory distinguishes between sensory processing and non-sensory decision rules in the brain. ► Sensory processing is a complex process involving both the sensory representation and its readout to form the decision variable that guides behavior. ► Many studies that examined the neural basis for the psychometric function focused on properties of the sensory representation. ► This article reviews recent work characterizing properties of the readout process and how it can affect the psychometric function, particularly in the context of learning.