(Eckerman, Lanson, and Cumming, 1968), and schedules of reinforcement (Ferster, 1960), but also with the use of this procedure as a baseline from which effects of drugs , hypnosis (Ferster, Levitt, Zimmerman, and Brady, 1961), and brain lesions (Spaet and Harlow, 1943) Procedure Preliminary training. After magazine training, the response requirement was increased to a fixed ratio of five responses (FR 5) on the center key, which was alternately illuminated with three hues (amber, red, and green). Responses on the illuminated key were reinforced with 3-sec grain magazine presentation.

Eleven age groups of 22 each were shown the Necker cube illusion on three separate trials, using a different instructional set for each. Frequency of reversals was determined by the number of times the subject indicated that the "X" on the cube changed perspectives during a 90-sec trial. The results of a 3 by 11 analysis of variance revealed a .01 level of significance between the peak age groups, 25 and 45 years, and the 55-, 65-, 75-, 85-, 95-, 5-, and 10-year·old groups. These data suggest that young and old people were less able to reverse visual perspectives than the middle age groups.Since the original study by Necker (1832), most perceptual research using the Necker cube examined the illusory quality of perceptual reversals. Results showed that factors such as brain damage (Cohen, 1959), heart rate, cold (Roland, 1970), retinal anoxia (pickergill & Jeeves, 1964), and hyperventilation (Tar· gowski & Baer, 1966) affected reversal rates, while lumination and the presence of cataracts did not (Heath, Ehrich, & Orbach, 1963). These studies suggest that physiological factors are important in determining the number of perceptual switches recorded. A further assumption is that the aging process may create percep· tual changes. Results with the Miiller-Lyer, Ponzo, and Titchner circles illusions follow this hypothesis.In that the Necker cube has not been used to test the effects of age on reversal rate, the present study will examine whether different age groups report a similar or divergent number of reversals on the Necker cube illusion using different instructional sets varying in degree of structure. Also, two additional perspectives of the Necker cube have been identified (Holt & Matson, 1974) and used for this experiment as a measure of perceptual reversabili ty. Varying instructional sets and adding two new perspectives may prove to be a useful development in creating a more sensitive instrument for examining visual perceptual differences. METHOD Subject3Two hundred and forty-two volunteers were obtained from the general population of upper New York State and central Illinois. Of this sample, 11 males and 11 females were chosen from each of the following mean age groups: 5, 10, 15, 25, 35, 45, 55, 65, 75, 85, and 95 years. Equal portions of the sample were collected from both sections of the country. Many of the 85-and 95-year-<>lds lived in nursing homes. ApparatusA Kodak 800 Carousel slide projector was used to present the stimulus and a battery-powered digital counter aided in 4 recording. A hand-<>perated stopwatch was incorporated to time duration of stimulus exposure. ProcedureThe experiment was divided into three separate 90·sec trials; each was composed of different instructional sets. The first two sets of instructions prompted spontaneous, or random, reversals in which the subjects could change the "X" in any order. Instructions on Trial 3 specifically directed the subject where to see the "X" on the cube.Frequency of reversals consisted of the number of times the subject pressed the detonator on...

No abstract

Two new visual perspectives of the Necker cube have been noted with an emphasis on the use of these perspectives in perceptual research. Twenty-five high IQ children ages 7, 8,9,10, and 11 and 25 low IQ children ages 7, 8, 9, 10, and 11 were asked to reverse the Necker cube under three different instructional sets. The second and third sets of instructions involved the training of four different visual perspectives of the Necker cube. The results showed that IQ and age both significantly effect the number of reversals of the Necker cube. Except for 11-year-olds, low IQ children perceived fewer reversals than high IQ children.