Variables related to reported learning in brief experiential groups held at professional meetings

Reports of learning from 119 participants of 18 general psychodynamic groups from the 1981 and 1982 annual meetings of the Canadian Group Psychotherapy Association were investigated. Two main learning factors emerged from a factor analysis of participant ratings, learning about oneself in a small group (factor one) and learning how to be an effective leader with professional skills (factor two). Participants reported moderate to considerable learning for both factors even though the stated task of the groups did not emphasize the learning of professional skills. Relationships between several classes of variables (group, leader, demographic) and reported learning were studied. Results that were consistent with several previous investigations were found. The discovery of a participant, sex-difference finding, i.e., greater reported learning by the women, generated a number of questions that may be addressed in future investigations.This article was derived from a paper presented at the Fourth Annual Meeting of the Canadian Group Psychotherapy Association, October 27, 1983, Banff, Canada.     

Presidential threats and the secret service in a free society

In September 1981, a symposium of distinguished mental health practitioners from various clinical, administrative, research, and legal disciplines was conducted on the topic of “Behavioral Science and the Secret Service,” under the sponsorship of the National Academy of Sciences, Institute of Medicine. The article combines a study of the symposium's written conference summary, the author's experience as legal counsel to a state security hospital, and research into federal cases that have interpreted the so-called “Presidential Threat Statute” (18 USC 871) in order to discuss the role of the Secret Service in protecting elected federal officials from physical harm. The potential for increasing practical cooperation between the Service and state mental health systems is also discussed.     

Adaptation to uniocular image magnification: Is the underlying shift proprioceptive?

Ss wore a 4% overall size lens (OSL) before one eye while they engaged in 20 min of binocular exploration of a typical indoor environment. Tests before and after the exposure period were conducted to determine whether or not OSL exposure leads to shifts in depth judgments based on binocular disparity. No significant shifts were observed. These results were applied to an evaluation of two contrasting hypotheses that have been proposed to explain adaptation to meridional size lens (MSL).     

Frequency response characteristics for sinusoidal movement in the fovea and periphery

Threshold sensitivity was measured for sinusoidal movement of bright 1-deg lines against a dark background as a function of oscillation frequency and retinal location. Sensitivity was greatest in the fovea and at a frequency of 1–2 Hz. Peripheral sensitivity was more narrowly tuned than foveal sensitivity. The presence of a stationary reference line affected mainly the foveal sensitivity. The results are interpreted as evidence for both position- and velocity-sensitive mechanisms in the movement detection system.     

The detection of visual intensity differences by pigeons

Pigeons were trained in a conditional discrimination procedure to discriminate between visual stimuli that varied in intensity. The magnitude of the intensity difference ranged from 0.80 to 0.05 logarithmic units. Psychometric functions were calculated from the data and the mean difference threshold for the 11 subjects was approximately 0.12 logarithmic units. A signal-detection analysis of the data suggested that stimuli that were below the calculated threshold were detectible to the subjects.     

BASIC subroutines for on-line experiments using Hewlett-Packard computers

Modifications of the Hewlett-Packard version of the BASIC language to permit its use in data acquisition and control of on-line experiments are described. The resulting software system is an easy-to-use interpretative compiler.     

On the detectability of straight lines in visual noise: An extension of French’s paradigm into the millisecond domain

We report the results of a study that investigated the effects of four experimental parameters on the tachistoscopic detectability of dotted lines in a noisy background consisting of dynamic patterns of identical dots. Characteristics of the lines that were explored included dot spacing, dot numerosity, and line orientation. Dot spacing was shown to be the most powerful parameter in determining the masking effect: the closer the dots, the more easily the line was detected. Increasing the number of the dots was also effective in increasing the detectability of a line, but only up to a limit of five dots. The orientation of the line, on the other hand, did not alter its detectability. Increasing the density of the visual masking noise monotonically reduced the detectability of the line. These studies are an extension of French’s (1953, 1954) work, differing mainly in the fact that the stimulus material was presented tachistoscopically rather than in a mode that allowed prolonged (up to 5 sec) examination of the figures. Thus, they put the results in a domain in which physiological interpretations may be more critically evaluated. A comparison of the results suggests that essentially the same sorts of cognitive mechanisms are operating in the millisecond domain as in the longer exposures. This suggests that simple neurological models utilizing the concept of feature filters or detectors may be being prematurely applied to relatively complex perceptual processes.     

A primate restraint and handling system for auditory research

A set of devices is described that enables daily handling and restraint of large primates. The animals live in cages and wear a special collar that fits into a modified primate restraining chair. A chain and pole arrangement simplifies the daily chairing procedure. A method of head restraint and earphone mounting is also described.