Robert H. Pollack

Mueller-Lyer Illusion: Effect of Age, Lightness Contrast, and Hue

Mueller-Lyer figures produced by lightness contrast (white on black) and by hue contrast in the absence of lightness contrast (red, yellow, green, or blue on gray) were presented to subjects aged nine to adult. Contrary to Piagetian expectations, the illusion magnitudes resulting from the colored figures did not decline with age.

Magnitude of the Mueller-Lyer illusion in children as a function of pigmentation of the Fundus oculi

Fifteen Ss (13 Negroes, two whites) rated as having dense or dark pigmentation at the Fundus oculi were compared with 20 Ss (one Negro, 19 whites) rated as lightly pigmented with respect to their sensitivity to a part of the Mueller-Lyer figure. The darkly pigmented Ss were significantly less sensitive than the lightly pigmented Ss. Biserial correlation of magnitude of illusion with pigmentation rating yielded a coefficient of −.745.

Contour detectability threshold as a function of chronological age.

Evidence from various areas of investigation was cited to support the view that an aging process in the visual receptor mechanism might be expected to bring about a rise in contour detectability thresholds. Support was also garnered for the view that certain geometrical illusions which decline with chronological age are determined by the degree of figure-ground contrast (or contour strength) of their inducing lines. Two experiments were carried out, the first to measure contour detectability thresholds at 5 age levels (8 yr. to 12 yr.), and the second to measure the magnitude of a modified Mueller-Lyer illusion at these age levels. Both experiments yielded significant results in the expected directions. Correlation of the results based on common Ss yielded a significant negative r. Intelligence correlated negatively to a significant degree with contour detectability threshold, but not with magnitude of illusion. Possible implications were discussed.

Acute alcohol intoxication and female orgasmic response

Abstract This study tested the hypothesis that increasing levels of acute alcohol intoxication are related to systematic changes in female orgasmic experience reflected by physiological, behavioral, and cognitive indices. Using a repeated measures design with monthly experimental sessions, each of 18 university women were sustained at four different blood alcohol concentrations (BAC) in counterbalanced order prior to viewing sexually explicit videotapes and engaging in masturbation to orgasm. Measures of vaginal blood volume obtained by means of a vaginal photoplethysmograph and complemented by a behavioral latency measure showed a progressive and systematic depressant effect of alcohol on orgasmic responding. Higher BACs were associated with longer orgasmic latencies and decreased subjective intensity of orgasm, while, paradoxically, women reported significantly greater sexual arousal and orgasmic pleasurability under conditions of moderate and high alcohol intoxication. Results have implications for tre...

Alcohol effects on the orgasmic‐ejaculatory response in human males

Abstract Increasing levels of alcohol intoxication, as measured by blood‐alcohol concentration, produced significant degradation in male masturbatory effectiveness. Employing psychophysiological indices of orgasm and several subjective criteria, a progressive and systematic effect of alcohol on the orgasmic‐ejaculatory response was found. Results are discussed with implications for the etiology, treatment, and prevention of alcohol‐induced sexual dysfunction in males.

Racial differences in pigmentation of the Fundus oculi

An empirical evaluation of the correspondence between skin pigmentation and density of pigmentation in the Fundus oculi seemed desirable as a measure preliminary to further study of possible racial differences in perception. Fourteen Negro and 26 Caucasian males between the ages of 8–12 (matched for age on an approximately one to two basis), were rated for density of fundus pigmentation on a four point scale by an opthalmologist. A close correspondence between race and fundus pigmentation density was found, with 12 of the 14 Negro children categorized in a distinctly denser class of fundus pigmentation than 24 of the 26 Caucasian children.

SIMULTANEOUS AND SUCCESSIVE PRESENTATION OF ELEMENTS OF THE MUELLER-LYER FIGURE AND CHRONOLOGICAL AGE.

Optico-geometrical illusions may be dichotomized into those whose magnitudes decrease with an increase in chronological age (Type I) and those whose magnitudes increase with chronological age (Type II). The former illusions appear to be determined largely by stimulus variables and the state of the receptor system, and not at all by intellectual functions. The latter appear to depend upon the comparison of visual stimuli separated by space or time, such comparisons seeming to necessitate intellectual functioning. In this experiment the method of presentation of a Type I illusion was altered so that its parts were presented in succession rather than simultaneously. It was predicted that such alteration would reverse the direction of illusion, reverse its developmental pattern, and would produce a correlation with measured intellectual capacity, all of which would be characteristic of a Type II illusion. Ss were school children in Grades 2 to 5. All predictions were confirmed. The implications of the results for an overview of perception in general were discussed.

The effect of simulated receptor aging on two types of visual illusions

A Type I (Delboeuf illusion) and Type II (Usnadze effect) illusion were viewed both through and without a yellow filter by younger and older groups of adults. The filter served to simulate receptor aging by decreasing the visual sensitivity of the Ss. The magnitude of the Type I illusion decreased at both age levels when viewed through the filter, but the magnitude of the Type II illusion did not change. The results indicate that different mechanisms produce the ontogenetic trends of the two types of illusions.

Magnitude of the Mueller-Lyer illusion as a function of hue, saturation, and fundus pigmentation

One hundred Ss, 50 male and 50 female undergraduate students, were tested to determine the effects of saturation, hue, and fundus pigmentation on the magnitude of the Mueller-Lyer illusion. It was found that the highly saturated (chroma 12) red figure produced a smaller illusion than the unsaturated (chroma 6) red or blue figures. Only the magnitude of the illusion produced by the highly saturated yellow figure correlated significantly with the lightness of fundus pigmentation.

Block-design performance as a function of hue and race ☆

Abstract The block-design subtest of the WISC was presented in two forms, the standard red/white and an alternative blue/yellow, to two groups of fourth- and fifth-grade children. Twenty black children and 20 white children performed the red/white task with no significant differences between their scores. Another 20 black and 20 white children performed the blue/yellow task showing a significant interracial difference. Within the group of black children there was also a significant difference between the red/white design scores and the blue/yellow design scores. It is proposed that genetically determined differences in the pigmentation of the fundus oculi account for these results.