Choice behavior in a discrete-trial concurrent VI-VR: A test of maximizing theories of matching

Rats were trained on a discrete-trial procedure in which one alternative (VR) was correlated with a constant probability of reinforcement while the other was correlated with a VI schedule which ran during the intertrial intervals and held the scheduled reinforcer until they were obtained by the next VI response. Relative reinforcement rate was varied in series of conditions in which the VR schedule was varied and in series in which the VI was varied. Choice behavior was described well by the generalized matching law, although moderate undermatching occurred for all subjects. Contrary to the predictions of molar maximizing (optimality) theories, there was no consistent bias in favor of the ratio alternative, and the sensitivity to reinforcement allocation was not systematically affected by whether the ratio or interval schedule was varied. The results were also contrary to momentary maximizing accounts, as there was no correspondence between the probability of a changeover to the VI behavior and the time since the last response to the VI alternative. Neither variety of maximizing theory appears to provide a general explanation of matching in concurrent schedules.     

Detection of increments in noise intensity by monkeys

Monkeys were trained to detect 100-msec increments in the intensity of continuous white noise. A response on one of two bars was reinforced with some probability if it conformed to the presence or absence of the increment on that trial. Stimulus parameters of background intensity, increment size, and probability of increment presentation were varied, and response probabilities and latencies were recorded. The task was analogous to the "yes-no" task used in human psychophysics. Data analysis within the context of signal-detection theory revealed response biasing toward one bar or the other to be related to the probability of increment presentation, whereas sensitivity depended on the combination of increment size and background noise intensity. Weber's law was found to hold for a large range of background intensities in that the sensitivity to relative intensity increments varied little. Performance was compared to that of an ideal observer that uses samples of the envelope of the noise waveform on which to base its responses.     

Muscle tension in human operant heart rate conditioning

The physiological mechanism involved in human operant heart rate conditioning is not known. If skeletal muscle tension is a mediator, it should be possible to generate significant heart rate increases by inconspicuous voluntary muscle tension. Eleven subjects were instructed to generate inconspicuous muscle tension for 90-second periods. No gross muscle movements were observed, but average heart rate during the trials was over 13 beats-per-minute greater than pre-trial base lines. Respiratory pattern changes and surface electromyogram changes did not reliably correlate with heart rate increases. Inconspicuous muscle tension could be a mediator in human operant heart rate conditioning, and cannot be ruled out by absence of change in respiratory pattern or electromyogram.     

High-speed memory retrieval with auditorily presented stimuli

Two groups of 8 Ss memorized three lists of consonental phonemes. The length of the memorized lists (M) was one, two, and four phonemes. Test words were presented, and reaction time (RT) for S to say whether or not the word started with a member of the memorized list was measured. RT increased with M. In one group, the phonemes comprising the memorized sets were dissimilar. RT increased linearly with M for that group. In the other group, the phonemes comprising the sets were similar. The function relating RT to M appeared to deviate from linearity. Even after extended practice, all the evidence was consistent with a somewhat modified serial model of memory retrieval.     

Choice reactions with a null stimulus event

A procedure for producing a null stimulus (S₀) in a CRT task is described. The S₀ produced is shown to elicit reactions that have characteristics of responses given to stimuli (S₁) that appear in regular CRT tasks. It was also discovered that, in this procedure, the initiation of S₀ sampling comes earlier than that of S₁ when S₀ and S₁ appear in the same CRT task. The nature of S₀ as well as the apparent reasons for its early sampling are discussed.     

Environmental Attention,Affect, and Altruism1

Three experiments were conducted concerning the effect of attention to positive or negative images of the physical environment on altruistic behavior: I. Some subjects listed and described aspects of their residential environments that were particularly pleasant while others described particularly unpleasant aspects. II. Subjects were exposed to slides of either attractive or unattractive outdoor environments. III. Subjects viewed slides of either attractive or unattractive environments while adopting an attentional set that focused only on positive or negative aspects of the slides. After these manipulations, subjects in each experiment encountered an ostensibly unrelated confederate who sought their assistance as a favor. Experiment I subjects who had thought about pleasant environments spent significantly more time helping than those who thought about unpleasant enviornments. Experiment II subjects who saw slides of attractive environments offered significantly more aid for a longer time period than subjects who saw slides of unattractive environments. Experiment III subjects who focused on positive aspects of attractive enviornments gave more help than subjects who focused on negative aspects of attractive environments, though overall differences were not significant. Attentional set produced no differential helping effects in subjects who had viewed unattractive environments. In all three experiments mood or affect was discussed as mediating the impact of environments on behavior.     

Selecting University Lecturers: What is and Should be Done

This paper presents a survey designed to identify the procedures used by British university departments when selecting academic staff and compare them with typical practice in other UK organizations. The results indicate that, compared with other large organizations, university departments make much less use of psychometric tests or assessment centres, relying heavily on the application form, a single interview and a presentation. There were no differences between academic departments of English, Biology or Psychology and the level of academic appointment only affected the composition of the interview panel. Possible reasons for the failure to use modern objective methods of selection are considered. It is argued that universities should apply more objective selection methods based on a full analysis of the competencies required of the higher education lecturer.     

Effects of Probabilistic Rewards on Recycling Attitudes and Behavior1

Two studies compared the attitudinal and behavioral effects of certain rewards and lotteries. In a laboratory experimental study, lotteries produced significantly more attitude change than cash payments. The greatest attitude change occurred among lottery winners. In a quasi-experimental field study, subjects rewarded with lottery tickets recycled glass and newspaper more frequently than subjects receiving other individual or group rewards. Attitude change was not affected by the type of reward Implications for the design of incentive programs to increase prosocial behavior are discussed