Abstract
Improvements in perceptual performance due to extended experience have been hypothesized to arise from a variety of perceptual mechanisms. Detection and discrimination thresholds have been the primary measure of performance in support of such hypotheses. The present work explores the possibility that decisional information may also play a role in perceptual skill acquisition, at least over some portion of the acquisition period. We present the results of an experiment designed to provide evidence for the potential roles of both perceptual and decisional factors. Stimuli were gray-scale Gabor patches and the critical variation was stimulus contrast. Individual observers each provided data used for estimates of detection and discrimination thresholds, discriminability and bias measures, reaction times, and scaling of magnitude estimates. In addition, we provide a description of a dynamic model capable of simultaneously predicting performance on all of these measures. The model is specified as a system of differential equations augmented with stochastic elements and decisional thresholds. The modeling architecture is flexible enough to allow a set of competing hypotheses regarding the roles of perceptual and decisional influences to be represented. These representations (a) are compared with respect to their ability to simultaneously fit all of the dependent measures, and (b) are used to identify experimental conditions that and empirical regularities that allow the candidate hypotheses to be tested and falsified.