Kinetic disruption of optical texture: The perception of depth at an edge

An examination of the changes in visual stimulation that result from changes in the occlusion of one surface or object by another suggests two hypotheses about the motion-carried information that is sufficient for the perception of the relative depth at an edge as well as the perception of occlusion. Ss’ reports when shown displays containing only this information give strong support to the hypotheses.     

An adjusting avoidance procedure with multiple auditory and visual warning stimuli

Male albino rats were trained on an adjusting avoidance schedule in which each lever press accumulated a given amount of shock-free time. Multiple auditory and visual stimuli were programmed for each discrete temporal distance from the shock in an effort to place the avoidance behavior under the control of the shock proximity. The effects of the stimuli were further examined by presenting part of them and then by removing them altogether. With the combined auditory and visual stimuli, the rat spent most of the time relatively close to the shock and usually started to respond only when the shock was near. With the visual stimuli only, the rat kept the shock at intermediate temporal distances and responded more variably. The behavior with the auditory stimuli alone was quite similar to that produced by the combined stimuli, thus indicating that the auditory stimuli exercised the greater control. When all stimuli were removed, the animal usually kept the shock as far away as the procedure permitted. When only a single pre-shock stimulus was presented, the rat remained quite close to the shock and started to respond predominantly in the pre-shock step.     

Some statistical treatments compatible with individual organism methodology

Consider experimental treatments with consequences so irreversible that baseline performance cannot be recovered. The conventional method of assessing the effects of such treatments by statistical means involves separate experimental and control groups. An alternative proposed here is to administer the experimental treatment to each subject, one subject at a time and in a random order; whenever any subject receives the experimental treatment, those subjects which have not yet received it receive a control treatment. This procedure permits results significant at the one-tailed 0.05 level to be obtained with four subjects; if a two-group procedure evaluated by means of the U test is used, a minimum of six subjects is needed for the same significance level. More generally, the procedure permits equal sensitivity to any experimental effect with over 30% fewer subjects than a two-group procedure. Extensions of the basic method are made to a variety of levels of the experimental treatment and to treatments without irreversible effects, and limitations of the method are discussed.     

Aspirations and Expectations of Physically Impaired High School Seniors

Physically disabled and non-disabled high school seniors' educational and vocational aspiration-expectation discrepancies were compared. No significant differences were found when the two groups were matched for cumulative GPA and level of father's occupation. GPA's and father's job levels of disabled students were significantly lower than those of the non-disabled. When not matched, disabled students' vocational aspiration-expectation discrepancies were significantly higher than those of the non-disabled. Higher aspiration than expectation for the highest vocational and educational levels, professional training, and employment were the major sources of differences expressed by seniors.     

Cortical steady-potential shifts in conditioning

Cortical steady-potential shifts obtained from nonpolarizing electrodes chronically implanted in freely moving cats and rats reveal cortical activation related to urgency of response to unconditional and conditional stimuli. Such shifts appear relatively independent of activation in the rhythmic electrocorticogram and are related to higher levels of activation. Shifting is found to be modulated by drive and level of learning, suggesting a correlation with the proposed reaction potential of Hull. Both approach and avoidance “urgency” are reflected in the onset slope and amplitude of SP shifts in a manner suggesting modulation of cortical activation by the effects of behavioral regulation of stimulus conditions.     

Some observations and measurements of the Pulfrich phenomenon

The Pulfrich pendulum was evaluated as a potential screening device for the detection of anomalies of binocular vision. For this purpose, a booth was set up at the Kentucky State Fair (1964) and the general public invited to observe the pendulum and record their responses with the equipment provided. The obtained results indicate that a dichotomy can be achieved between those who have binocular vision and those who do not. However, gradations of binocular vision from poor to good cannot be achieved with the pendulum as presently understood. Contrary to explanatory theory the characteristic shape of the seen pendulum path was asymmetrical following the rule that the path was displaced away from the observer on the side of the filtered eye.     

An investigation of several parameters of the horizontal-vertical illusion

Length of standard line, degrees of lateral separation of H and V stimuli, and which line served as standard or comparison stimulus were systematically varied in a 4 by 3 by 2 factorial design on the horizontal-vertical illusion. When illusion affects were averaged under H- and V-standard conditions, a negative relationship obtained between magnitude of illusion and length of line. With. vertical as standard, the illusion increased as a function of lateral separation of stimuli, but decreased with horizontal as standard. These differential trends for H- and V-standard conditions contributed to the unsystematic relationship between the size of the illusion and progressive displacement of H and V lines. The illusion curves for three lengths of standard line across degrees of lateral separation were similar. The findings are viewed as incompatible with explanations of the H-V illusion involving the so-called “error of the standard.”     

Aversive control of self-injurious behavior in a psychotic boy

Two studies are reported which indicate how quickly and effectively chronic self-injurious behavior was controlled in a 9-yr-old blind psychotic boy. In the first study, the self-injurious responses were punished by contingent withdrawal of human physical contact. In the second study, response-contingent electric shock was employed.