Abstract

We have developed a detection paradigm in which two identical briefly pulsed point sources are presented on each trial with the observer reporting seeing zero, one, or two stimuli. These responses are gathered as a function of stimulus intensity and psychometric functions for seeing either stimulus and for seeing both stimuli are calculated. Psychometric functions are obtained for mid-spectral and long wavelength stimuli. A model positing binomial sampling of L and M cones and Poisson-distributed quantal noise is used to fit the psychometric functions. Three theoretically important parameters are estimated by the model: the L/M cone ratio, the number of quanta per cone needed for threshold detection, and the effective number of cones contributing to threshold detection.

© 1989 Optical Society of America