Duration discrimination between weak test lights

Maloney and Wandell [Vision Res. 24, 633-640 (1984)] describe a model of the response of a single visual channel to weak test signals. In the model an initial continuous visual response is randomly sampled, and each sample gives rise--with a probability that increases with the magnitude of the sample--to a discrete detection event. The authors derive a parameter-free prediction for the upper bound on the discriminability of two lights of different durations. In this paper we describe an experimental test of that prediction. We find that the model accurately distinguishes between discrimination performance under conditions where both test lights are detected by a single channel and conditions where the test lights are detected by different channels.