Assessing potential reinforcement-like effects of brief stimuli unrelated to food reinforcers

It is widely assumed that reinforcers are biologically relevant stimuli, or stimuli that have been associated with biologically relevant stimuli. However, brief, arbitrary stimuli have also been reported to have reinforcement-like effects, despite being unrelated to biologically relevant stimuli like food. The present study explored the potential reinforcement-like effects of brief stimuli across 5 experiments. In Experiments 1 through 4, pigeon subjects responded for food reinforcement and brief stimulus presentations in a 2-component multiple schedule. Neither baseline response rates nor resistance to change during disruption tests were systematically greater in a component with versus without brief stimulus presentations. Increasing the rate and duration of brief stimulus presentations in Experiment 4 did not reveal reinforcement-like effects when compared directly with food. In Experiment 5, pigeons chose between independent terminal links in a concurrent-chains procedure. Across conditions, varying the location, duration, and rate of brief stimulus presentations in the terminal links had no systematic effects on preference. In contrast, varying rates of food reinforcers resulted in large and reliable shifts in preference. Therefore, the present study found no systematic evidence that brief stimuli unrelated to food reliably increase response rates, resistance to change, or preference. These data demonstrate the value of systematic replication, and a behavioral momentum approach to assessing potential reinforcement-like effects.     

Book Review: Cultural Psychotherapy: Working with Culture in the Clinical Encounter. By Karen M. Seeley. New Jersey: Jason Aronson,Inc, 2000, 266 pp., ISBN 0-7657-0224-X

Pastoral Psychology -     

Prevention of nonadherence to nonsteroidal anti-inflammatory medications for newly diagnosed patients with juvenile rheumatoid arthritis.

Adherence to medications for chronic pediatric diseases decreases overtime. This randomized controlled trial evaluated a clinic-based, nurse-administered educational and behavioral intervention to prevent the anticipated drop in adherence to nonsteroidal medications among newly diagnosed patients with juvenile rheumatoid arthritis. Thirty-four participants completed the study (mean age = 8.44 years, SD = 3.96), including 19 in the experimental group and 15 in the standard-treatment (education) control group. There were significant group and Group x Time effects for adherence (assessed with an electronic monitor over a 13-month period) favoring the experimental group. In contrast, the groups did not differ significantly in disease activity or functional limitations. Factors that may have prevented detection of differences in these health parameters are dicussed.     

DIMENSIONS COGNITIVES ET COMPORTEMENTALES CHEZ LES JOUEURS RÉGULIERS ET OCCASIONNELS AU BLACKJACK

Empirical studies in the psychology of gambling have revealed at least two well supported findings: (1) irrational cognitions outnumber rational cognitions during gambling (Gaboury and Ladouceur, 1987; Ladouceur, Gaboury, Dumont and Rochette 1988); (2) risk-taking behavior increases as a function to exposure to gambling activities (Ladouceur, Mayrand and Tourigny 1987; Ladouceur, Tourigny and Mayrand 1986). The present study compared regular and occasional gamblers on cognitive and behavioral measures during a blackjack session using the thinking aloud method. The results confirmed that regular players emitted more irrational thoughts than occasional gamblers. The theoretical and practical implications of those results are discussed within the general context of the psychology of gambling.     

The assessment of child abuse potential and the prevention of child abuse and neglect: A policy analysis

A frequently advocated strategy for increasing the efficiency of child abuse prevention programs is to deliver prevention services to "high-risk" populations. This article critically reviews procedures for the reliable and valid assessment of child abuse potential within an ecological perspective. Factors that limit the usefulness of child abuse risk assessment are discussed. These factors include the uncertain criteria of child abuse and neglect, the low base rate of the phenomenon, and the financial and social costs of such procedures. Finally, the prevention implications of the current and future state of the art in child abuse risk assessment are considered and preventive interventions that do not depend on individual case risk screening are advocated.     

Processing resources and age differences in working memory

This study investigated the performance of young and old subjects on a modified version of the working memory task developed by Baddeley and Hitch (1974). Subjects were required to verify a set of sentences of varying complexity while they repeated aloud zero, two, or four words. The older subjects took longer to verify the sentences, especially when the sentences were grammatically complex, but the effect of concurrent memory load on verification latency was the same in both groups. These results cast doubt on the notion that there is an age-related decline in one general pool of processing resources. They also suggest that older people have greater difficulty with the active processing aspects, rather than with the passive holding aspects, of working memory tasks.     

Perception of translational heading from optical flow

Radial patterns of optical flow produced by observer translation could be used to perceive the direction of self-movement during locomotion, and a number of formal analyses of such patterns have recently appeared. However, there is comparatively little empirical research on the perception of heading from optical flow, and what data there are indicate surprisingly poor performance, with heading errors on the order of 5 degrees-10 degrees. We examined heading judgments during translation parallel, perpendicular, and at oblique angles to a random-dot plane, varying observer speed and dot density. Using a discrimination task, we found that heading accuracy improved by an order of magnitude, with 75%-correct thresholds of 0.66 degrees in the highest speed and density condition and 1.2 degrees generally. Performance remained high with displays of 63-10 dots, but it dropped significantly with only 2 dots; there was no consistent speed effect and no effect of angle of approach to the surface. The results are inconsistent with theories based on the local focus of outflow, local motion parallax, multiple fixations, differential motion parallax, and the local maximum of divergence. But they are consistent with Gibson's (1950) original global radial outflow hypothesis for perception of heading during translation.