Abstract
Last year (VSS 2005) we introduced a novel stereo-illusion, which we called the Flash-Pulfrich effect (FPE). While the classical Pulfrich Effect (PE) describes depth perceived when the half-images of a moving object have unequal brightness, the FPE describes depth perceived when one of the half-images is intermittently strobed, while the other is presented continuously.
We now ask whether and how the FPE and PE are related. Our data shows that the magnitude of the FPE is greater than that of the PE. This does not, however, preclude the possibility that a single mechanism might account for both.
Accordingly, we have developed a computational model for the FPE based on the basic response properties of LGN neurons. The model filters the input (in space and time) with a DoG spatial filter and the biphasic temporal impulse response of LGN neurons. We show that this model predicts differences in magnitude between the PE and FPE. We also examine how the magnitudes of the PE and FPE vary when basic stimulus parameters are changed (spatio-temporal frequency and retinal illuminance). We show that the trends in the stimulus dependence of the two effects are predictions of the model.