A Serial Afterimage Experiment in Clinical Diagnostics

Abstract

Successive change in the size of negative afterimages repeatedly projected upon a screen was measured in a group of 87 psychiatric patients and a control group of 27. Primitive‐hysteroid subjects were characterized by fluctuating serials, compulsives by small size changes of short duration, anxiety cases by progressively growing, dark, achromatic images, and psychotics by sudden contractions to size‐constant or concrete images. A tentative finding for depressives was also presented and discussed.

Psychopathology in childhood and adolescence as reflected in projected afterimage serials

“…In other words, even the adult A1 cannot merely be regarded as the mechanical result of certain conditions pertaining to the stimulus and projection surface. In individuals suffering from manifest anxiety, for instance, we have shown how AIs become dark, even frightening, and/or cover an in-creasing part of the perceptual field (Smith & Kragh, 1967;Smith, Sjoholm & Nielzen, 1976). It has also been demonstrated that when anxiety is curbed by depressive retardation AIs are likely to gradually diminish and lose their darkness over the experimental serial (Smith, Kragh, Eberhard & Johnson, 1972;Smith & Danielsson, 1978b).…”

Projected Afterimages and Cognitive Maturity

“…The apparatus was a slightly modified version of the one used in previous investigations (Smith & Kragh, 1967). Stimulus consisted of a red square with a black fixation point in the middle.…”

“…If the above reasoning is correct the degree of adaptation to Emmert's law ought to reflect fundamental aspects of an individual's cognitive maturity. As already shown in a series of investigations (Smith & Kragh, 1967;Smith, Kragh, Eberhard, & Johnson, 1969) variations in afterimage size (together with hue and brightness) over a series of consecutive measurements can be exploited for the description of a variety of central regulatory mechanisms. The present problem, to be sure, concerns only the abandonment of size-constancy and related phenomena.…”

Individual Consistencies in Adaptation to Negative Afterimages and Spiral Aftereffects

“…The A1 experiment (Smith & Kragh, 1967) consisted of a semi-transparent screen of ground Plexiglas which moved along a horizontal bar. Attached to the front of the screen were two vertical rulers manipulated by S for the measurement of A1 size.…”

“…The two aftereffects to be compared here have both been utilized separately as indicators of various personality dimensions in clinical settings (Andersson, 1967b;Smith & Kragh, 1967;Smith, Kragh, Eberhard, & Johnson, 1969). .…”