When are supercomputers worth the bother?

The availability of the UNIX operating system on large supercomputers has greatly simplified the importation of research software from workstations and minicomputers. Supercomputers generally offer much greater memory and storage than do smaller machines, which may make their use mandatory for some large applications. Realization of the full performance offered by vectorizing supercomputers such as the Cray C90 sometimes requires modification of existing code. The use of high-level interpreters for the development of applications is recommended, to minimize the amount of compiled code that must be optimized.     

The φ-maze: A versatile automated T-maze for learning and memory experiments in the rat

The φ-maze is a novel implementation of the T-maze that can be used for various behavioral experiments. It consists of a start/goalbox from which a central alley leads to a choice point. Left and right arms return to the start/goalbox, where reinforcers are delivered. A holding chamber at the choice point can be used for delayed (non)matching-to-sample experiments. Lamps mounted under the translucent acrylic floor serve as visual stimuli. The design incorporates reliable and inexpensive automated guillotine doors and a modification of a commercially available pellet dispenser that allows the automated dispensing of Froot Loop reinforcers. The φ-maze has been used successfully in experiments involving spatial and visual alternation, visual discrimination, and delayed matching-to-sample.     

Circadian factors during sustained performance: Background and methodology

Cornell University Medical College, Westchester Division, The New York Hospital, White Plains, New York It is well established that there is a complex timekeeping mechanism in the human brain. This mechanism is associated with a variety of physiological and psychological rhythms having a period of about a day, and thus referred to as circadian rhythms. The circadian system has recently been modeled in terms of two underlying oscillators, one much more resistant to changes in routine than the other. These oscillators are considered to be endogenous, that is, internal to the organism, and not reliant for their existence upon changes in the person’s environment or general behavior. They thus continue to run even when the sleep/wake cycle is suspended, as in sustained operations. Thus, by their very nature, sustained operations require the individual to override the inputs that are coming from his or her circadian system (especially the indication that sleep is required). The aim of this paper is to provide a background to the area of circadian rhythms research, including a section on the methodology, so that the impact of the circadian system on sustained operations can be better understood.     

Relationships between perceptions of organizational size and the organizational choice process

Expectancy theory concepts were used to predict (a) the attractiveness of, (b) the amount of effort directed toward entering, and (c) the eventual choice of a job in relatively big and small work organizations. It was found, among a group of graduating seniors from a technical college, that antecedent perceptions regarding organizational size (expectancy, valence, instrumentality) were significantly related to the relative attractiveness of different-sized organizations and the number of job interviews taken with relatively big and small companies. In addition, economically tied extrinsic outcomes were seen as more readily attainable in big organizations, whereas certain intrinsic outcomes were perceived to be more easily obtained in small organizations.     

Social cues, cognitive style, error magnitude, and male performance on the Felt Figure Replacement Technique.

A series of studies was undertaken to determine possible factors contributing to low predictive utility for Felt Figure Replacement Technique (FFRT) scores from normal, adult males. It was first postulated that normal adult males, compared to normal adult females, are less sensitive to social cues present in the FFRT task. Twenty-six undergraduate males and the same number of undergraduate females were asked to replace both a) department store manikins, thought to be less abstract, and then b) felt figures. While task differences were obtained, these were not dependent on gender, nor did any overall gender differences occur for three types of replacement error. The second study involved 31 college males and 33 college females replacing both felt figures and a male and female confederate. It was assumed that differential attention to social cues would be more visible in this comparison. The general results were identical to the first study.     

Incentives and Seat Belts: Changing a Resistant Behavior Through Extrinsic Motivation

Because previously-attempted methods of increasing automobile seat belt usage have proven to be either ineffective or unworkable, a series of field experiments was carried out to test a technique of behavior influence utilizing a modest, positive incentive. In three separate studies, seat belt use of 4,745 drivers was observed as they drove out of a parking lot, after receiving one of several safety reminder leaflets. Some versions of the leaflet offered a gift certificate to a certain proportion of drivers who wore seat belts; other versions offered no incentive. The results showed that an incentive, regardless of the probability of payoff, raised belt use from about 15% to nearly 40%. Implications for future research and applications are discussed.     

The order of continuous,partial and nonreward trials and resistance to extinction

In the first experiment rats were given either 16 or 48 nonrewarded or continuously rewarded trials prior to 24 continuously or partially rewarded trials, followed by extinction. Increased resistance to extinction was found for increasing numbers of nonrewarded trials when they were followed by partial reward, but not when followed by continuous reward. Similarly, more continuously rewarded trials followed by partial reward tended to increase resistance to extinction. Because of the theoretical importance of the effect of continuous reward followed by partial, a second experiment was performed where the range of the number of continuously rewarded trials was extended to 0, 48, and 96. Contrary to many theoretical predictions, resistance to extinction increased as a function of increasing amounts of continuous reward.