PSYCHOPHYSICALLY PRINCIPLED MODELS OF VISUAL SIMPLE REACTION-TIME

Visual psychophysics has shown that the perceptual representation of a stimulus has complex time-varying properties that depend on the response characteristics of the channel on which it is encoded. A fundamental expression of these properties is the distinction between sustained and transient processing channels. A theoretical and mathematical framework is introduced that allows such properties to be incorporated into fully stochastic models of simple reaction time (RT). These models, the multichannel leaky stochastic integrators, combine a linear filter model of stimulus encoding with an accumulative decision process and yield a stimulus representation described by a time-inhomogeneous Omstein-Uhlenbeck diffusion process. Methods for obtaining RT distributions for these models are described, together with comparative fits to luminance-increment data obtained under conditions of channel pooling and channel independence.