Visual form integration and discontinuity detection.

Abstract

Two experiments were conducted to determine if discontinuity detection limits the visual integration of two stimuli presented successively. If this is the case, then presenting two dim stimuli should permit better integration than presenting two bright stimuli. In Experiment 1, five observers named the position of the missing dot in a 5 x 5 dot matrix. Twelve randomly selected dots were presented in each of two stimulus presentations. The stimuli varied in intensity in a ratio of 15:1 and stimulus onset asynchrony (SOA) varied between 50 msec and 80 msec. At the longer SOAs, presenting two bright stimuli led to a higher percentage of correct responses than presenting two dim stimuli. There was no difference between those conditions at the shorter SOAs. In Experiment 2, 12 naive observers rated the amount of integration of the same stimuli on a 7-point scale, under the same presentation conditions. Rated integration was higher with two dim stimuli than with two bright stimuli. These apparently contradictory results are explained in terms of Hawkins and Shulman's distinction between two kinds of visual persistence. It is concluded that subjects can respond to integration and discontinuity detection separately. No evidence was found that discontinuity detection limits the integration.

Effects of perceptual quality on hemispheric asymmetries in visible persistence

“…The present experiment, however, found an inverse size effect, which is defined by Long as being a hallmark of Type I persistence. A possible reason for this inconsistency may be that the experiments using the successive-field integration tasks that Long classified as being examples of Type II persistence were characterized by a large set of alternative responses: Eriksen and Collins (1968) had their subjects identify a CVC nonsense syllable, and Kinnucan and Friden (1981) had their subjects identify the missing dot in a 5 X 5 dot matrix. The present study, on the other hand, had a much smaller set of possible responses; in addition, the use of the LED display creates digits that are somewhat artificial in appearance and are potentially more confusable with one another.…”

Intensity dependence of perceived duration: Data, theories, and neural integration.

“…He held the ISI constant and also found a positive relationship between intensity and performance. Kinnucan and Friden (1981), DiLollo and Woods (1981), and DiLollo and Bourassa (1983) used a dot matrix instead of letters. A matrix was divided into two displays.…”

“…In Long and Sakitt's (1980) study, data were taken from Subject DV at the 50-ms flash duration. In Kinnucan and Friden's (1981) paper, the 60-ms ISI was used. In Adelson and Jonides' (1980) paper, the 200-ms cue delay was used.…”

Colour in visual displays

“…The number of scanning lines should correspond with the pitch of the shadow mask, but this is not always the case. Developments in high-resolution monitors and graphics boards have recently been reviewed [46].…”