Visibility-Invisibility Cycles as a Function of Stimulus-Orientation

Retinal rivalry and Troxler’s effect: A correlation

“…Figure 3 depicts the reported Troxler disappearances as a function of the spatial orientation of the stimulus line. The unusual shape of this curve, clearly indicating that the incidence of Troxler's effect is not equally probable at all retinal areas, has been reported earlier (Craig & Lichtenstein, 1953;Goldstein, 1967), and the basic wave-like pattern has since been repeatedly verified in this laboratory. Graphical analyses of these data for, each of the eight stimulus conditions as a function of observation interval was performed, and rivalry and Troxler are not identical phenomena, that is, Troxler is not the limiting case of rivalry where only one eye is stimulated with a contoured stimulus.…”

“…All responses were recorded on either one or two channels of an event recorde~Ck eye patch was placed over the (sighting) non-dominant eye during the Troxler trials. Instructions for these trials have been reported elsewhere (Craig & Lichtenstein, 1953), but basically, S was asked to visually fixate the center of the circle ( Fig. 1) and "pay attention" to the line extending into the periphery of his visual field.…”

Orientation effects on line afterimages

“…It is also surprising that such large differences were found between vertical and horizontal lines because almost every other orientation task shows these to be similar, as do the EEG recordings. The closely related disappearances that occur under steady fixation yield similar results for horizontal and vertical lines (Craig & Lichtenstein, 1953;Goldstein, 1967).…”

“…Preliminary studies had shown that a 3·min viewing period was generally long enough for the afterimage to have disappeared completely. peripherally viewed lines under steady fixation (Craig & Lichtenstein, 1953).…”

“…The use of whole and partial visibility indices enabled stochastic analyses of the afterimage fragmentation data in terms of the such effects (Craig & Lichtenstein, 1953;Cosgrove et aI, 1972). Upon this latter point, there is agreement between these studies and the above monocular afterimage experiments, if the complementary measure of afterimage invisibility is considered.…”