Effects of duration of masking stimulus and dark interval on the detection of a test disk.

Abstract

Detection thresholds for a test disk of light presented tachistoscopically were studied in one of four temporal relationships with a masking flash of variable duration. The conditions were: (a) simultaneous onset of test and mask, (6) simultaneous offset of test and mask, (c) offset of test coincident with the onset of mask, (d) onset of test coincident with the offset of mask. In each case, duration of mask was systematically varied. The four conditions were replicated with the mask substituted by a dark interval which interrupted an adapting field of light for a variable period. Masking increased with increments in the duration of the mask and was most severe under conditions where test and mask onset were simultaneous or where a dark interval preceded the simultaneous onset of test and mask. A dark interval within the adapting field always raised the detection threshold of the test disk. The results are consonant with the view that masking is due to "on-responses" in the visual system.2 Requests for reprints should be sent to John ,. . . "*:","]"" wa£! nrPSpn tpH Hurino-an Hogben, Department of Psychology, University of P e test s . timu l us was presented during an Western Australia, Nedlands, Western Australia, interruption of an Otherwise steady llght-6009.adapting field. Hogben (1971) found that 245

Visual masking by light offset: An experiment in reply to Hogben and DiLollo.

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their Condi-815 Triangles are means of 10 5s from Holzworth and Doherty [1971], The TS duration is actually a subject variable ranging from 20 to 30 msec., but it is represented as constant on the graph'as the mean of the TS durations.)…”

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their This document is copyrighted by the American Psychological Association or one of its allied publishers.…”

“…Earlier investigators (Baker, 1953;Battersby & Wagman, 1962;Crawford, 1947) had found evidence of this effect of light offset, but Baker (1963) essentially dismissed it as an artifact. Hogben and DiLollo (1972), Holzworth and Doherty (1971), and the present study allow an unequivocal interpretation in terms of sensitivity, which the earlier studies using classical psychophysical methodology did not.…”

“…This effect occurred within 60 msec, after TS onset. The present paper presents an extension of Holzworth and Doherty's evidence and argues with Hogben and DiLollo's (1972) contention that the darkness, rather than being a disruptive effect per se, "... enables masking effects associated with a reinstatement of the light field [p. 249].…”

Visual masking by light offset: An experiment in reply to Hogben and DiLollo.

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their Condi-815 Triangles are means of 10 5s from Holzworth and Doherty [1971], The TS duration is actually a subject variable ranging from 20 to 30 msec., but it is represented as constant on the graph'as the mean of the TS durations.)…”

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their This document is copyrighted by the American Psychological Association or one of its allied publishers.…”

“…Earlier investigators (Baker, 1953;Battersby & Wagman, 1962;Crawford, 1947) had found evidence of this effect of light offset, but Baker (1963) essentially dismissed it as an artifact. Hogben and DiLollo (1972), Holzworth and Doherty (1971), and the present study allow an unequivocal interpretation in terms of sensitivity, which the earlier studies using classical psychophysical methodology did not.…”

“…This effect occurred within 60 msec, after TS onset. The present paper presents an extension of Holzworth and Doherty's evidence and argues with Hogben and DiLollo's (1972) contention that the darkness, rather than being a disruptive effect per se, "... enables masking effects associated with a reinstatement of the light field [p. 249].…”

Metacontrast with black and white stimuli.

“…Extensive behavioural and physiological research (see, for example, Cornsweet, 1970, or Riggs, 1965 indicates that the visual system is very sensitive to brightness variation. Moreover, recent studies (Hogben & DiLollo, 1972;Holzworth & Doherty, 1971;Scharf & Fuld, 1972) show that brightness variation is important in backward masking. Some of the effects of black and white targets and masks observed here, therefore, could well reflect the visual system's processing of brightness changes.…”

Visual masking by light offset: An experiment in reply to Hogben and DiLollo.

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their Condi-815 Triangles are means of 10 5s from Holzworth and Doherty [1971], The TS duration is actually a subject variable ranging from 20 to 30 msec., but it is represented as constant on the graph'as the mean of the TS durations.)…”

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their This document is copyrighted by the American Psychological Association or one of its allied publishers.…”

“…Earlier investigators (Baker, 1953;Battersby & Wagman, 1962;Crawford, 1947) had found evidence of this effect of light offset, but Baker (1963) essentially dismissed it as an artifact. Hogben and DiLollo (1972), Holzworth and Doherty (1971), and the present study allow an unequivocal interpretation in terms of sensitivity, which the earlier studies using classical psychophysical methodology did not.…”

“…This effect occurred within 60 msec, after TS onset. The present paper presents an extension of Holzworth and Doherty's evidence and argues with Hogben and DiLollo's (1972) contention that the darkness, rather than being a disruptive effect per se, "... enables masking effects associated with a reinstatement of the light field [p. 249].…”

Metacontrast with black and white stimuli.

“…Extensive behavioural and physiological research (see, for example, Cornsweet, 1970, or Riggs, 1965 indicates that the visual system is very sensitive to brightness variation. Moreover, recent studies (Hogben & DiLollo, 1972;Holzworth & Doherty, 1971;Scharf & Fuld, 1972) show that brightness variation is important in backward masking. Some of the effects of black and white targets and masks observed here, therefore, could well reflect the visual system's processing of brightness changes.…”

Visual masking by light offset: An experiment in reply to Hogben and DiLollo.

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their Condi-815 Triangles are means of 10 5s from Holzworth and Doherty [1971], The TS duration is actually a subject variable ranging from 20 to 30 msec., but it is represented as constant on the graph'as the mean of the TS durations.)…”

“…Second, Hogben and DiLollo (1972) presented data directly supporting the hypothesis that light offset is the effective stimulus. If the reinstatement of light caused the disruption, then in their This document is copyrighted by the American Psychological Association or one of its allied publishers.…”

“…Earlier investigators (Baker, 1953;Battersby & Wagman, 1962;Crawford, 1947) had found evidence of this effect of light offset, but Baker (1963) essentially dismissed it as an artifact. Hogben and DiLollo (1972), Holzworth and Doherty (1971), and the present study allow an unequivocal interpretation in terms of sensitivity, which the earlier studies using classical psychophysical methodology did not.…”

“…This effect occurred within 60 msec, after TS onset. The present paper presents an extension of Holzworth and Doherty's evidence and argues with Hogben and DiLollo's (1972) contention that the darkness, rather than being a disruptive effect per se, "... enables masking effects associated with a reinstatement of the light field [p. 249].…”

Metacontrast with black and white stimuli.

“…Extensive behavioural and physiological research (see, for example, Cornsweet, 1970, or Riggs, 1965 indicates that the visual system is very sensitive to brightness variation. Moreover, recent studies (Hogben & DiLollo, 1972;Holzworth & Doherty, 1971;Scharf & Fuld, 1972) show that brightness variation is important in backward masking. Some of the effects of black and white targets and masks observed here, therefore, could well reflect the visual system's processing of brightness changes.…”