Stimuli inevitably generated by behavior that avoids electric shock are inherently reinforcing.

A molecular analysis based on the termination of stimuli that are positively correlated with shock and the production of stimuli that are negatively correlated with shock provides a parsimonious count for both traditional discrete-trial avoidance behavior and the data derived from more recent free-operant procedures. The necessary stimuli are provided by the intrinsic feedback generated by the subject's behavior, in addition to those presented by the experimenter. Moreover, all data compatible with the molar principle of shock-frequency reduction as reinforcement are also compatible with a delay-of-shock gradient, but some data compatible with the delay gradient are not compatible with frequency reduction. The delay gradient corresponds to functions relating magnitude of behavioral effect to the time between conditional and unconditional stimuli, the time between conditioned and primary reinforcers, and the time between responses and positive reinforcers.     

Effectiveness of a Comprehensive Worksite Stress Management Program: Combining Organizational and Individual Interventions

A comprehensive worksite stress management program consisting of self-management training and a stressor reduction process was evaluated in a pre-post, treatment-control design in four comparable facilities. Results showed that over a 3-month period those individuals attending self-management training improved on emotional well-being measures. Organizational data suggested that their work-units' productivity increased and absenteeism decreased over the same period. Results support the value of combining self-management training and stressor reduction to produce positive individual and organizational outcomes.     

Computing maximum likelihood estimates of loglinear models from marginal sums with special attention to loglinear item response theory

In this paper algorithms are described for obtaining the maximum likelihood estimates of the parameters in loglinear models. Modified versions of the iterative proportional fitting and Newton-Raphson algorithms are described that work on the minimal sufficient statistics rather than on the usual counts in the full contingency table. This is desirable if the contingency table becomes too large to store. Special attention is given to loglinear IRT models that are used for the analysis of educational and psychological test data. To calculate the necessary expected sufficient statistics and other marginal sums of the table, a method is described that avoids summing large numbers of elementary cell frequencies by writing them out in terms of multiplicative model parameters and applying the distributive law of multiplication over summation. These algorithms are used in the computer program LOGIMO. The modified algorithms are illustrated with simulated data. The author thanks Wim J. van der Linden, Gideon J. Mellenberh and Namburi S. Raju for their valuable comments and suggestions.     

Choice As A Function Of Reinforcement Ratios In Delayed Matching-to-sample

Pigeons were studied in two experiments using a delayed matching-to-sample task. In Experiment 1, 4 subjects were exposed to a task in which the proportion of reinforcement associated with matching and nonmatching, and the overall proportion of reinforcement associated with selecting each choice, regardless of the sample stimulus, were varied. Choice was sensitive to both proportions. A least squares regression analysis showed that Wixted's (1989) proportions of reinforcement model closely fit the data from Experiment 1; however, the model failed to make accurate qualitative predictions for some test conditions. In Experiment 2, 4 subjects were exposed to a delayed matching-to-sample task in which the retention intervals and the reduction in delay to reinforcement signaled by the onset of the sample stimulus were independently varied. When the retention interval was short and when the delay-reduction value of the sample stimulus was high, the sample exerted greater control over choice; the control by the overall proportion of reinforcements for selecting each choice stimulus was correspondingly low. Conversely, when the retention interval was long and the delay-reduction value of the sample stimulus was low, the sample exerted relatively less control over choice; control by the overall proportion of reinforcements obtained for selecting each choice stimulus was correspondingly high. A signal detection analysis found that sensitivity to reinforcement varied directly with retention interval. Data were also consistent with misallocation models. No evidence was found to suggest that pigeons ignore the rate at which selecting individual choice stimuli is reinforced, as has been reported in studies with human subjects.     

Maternal gestational stress alters adaptive and social behavior in adolescent rhesus monkey offspring

Data from rodent studies have indicated that stress experienced by pregnant mothers may result in behavioral and biological abnormalities in their offspring. However, few studies have examined the effects of prenatal stress on the offspring beyond the childhood period. In this study, 7 prenatally stressed (PNS) monkeys and 7 monkeys from undisturbed pregnancies were tested under mildly challenging conditions at 4 years of age. Following separation from cagemates and group formation, PNS monkeys showed more locomotion, abnormal and disturbance behavior than controls. Controls showed approximately six times more play than PNS animals. The PNS males showed the most clinging to others and the largest increase in contact with other animals over the period. Group differences were also found when the monkeys were observed as groups or alone in a playroom. Controls showed more explanatory behavior in the playroom, whereas PNS monkeys showed more inactivity. Control animals showed a decrease in distress vocalizations over time in the playroom, whereas PNS animals showed the opposite pattern. Control animals spent more time in proximity to and contact with cagemates than PNS animals. These results indicate that prenatal stress can have effects on adaptive and social behavior that persist into adolescence.     

Moral growth in medical students

Although students bring to medical school a fairly well established value system, the potential for moral growth through the medical school environment and experience is substantial. The educational environment poses a succession of developmental and adaptive tasks to be accomplished. Several of these tasks are discussed here, tasks that are value-laden and involve, directly or indirectly, the interplay of ethical theory and practice. During the past quarter century, the two influences that have had the greatest impact on the moral growth and moral reasoning capacity of medical students have been the incorporation into the medical school curriculum of courses in medical humanities and the admission to medical school of an increasing number of female students. The female students have brought to medical school a level or dimension of moral reasoning (morality as care or responsibility for others) to augment the male students' focus on rights and justice considerations.     

Consistency Orientation and Models of Social Behavior: Is It Not Time for West to Meet East

The study examined the cultural differences in inconsistency-reducing behaviors by testing the reactions of 110 Japanese and 169 American college students to the inconsistencies arising from a difference of opinion with a significant other on ego-involving issues. It was predicted that (1) the Japanese sample would show more inconsistency support than will an American sample; (2) The American sample will show more preference for active inconsistency-reducing responses than will the Japanese sample; (3) on the hypothesis that contemporary social psychology's models of humans is based upon the American stereotype of the "typical American," the first two predictions will be more strongly confirmed by comparing the American subjects' stereotype of the "typical American" than by comparing their own reported choices. The findings generally supported the first two predictions and strongly supported the third one.     

THE EFFECTS OF AN ENVIRONMENTAL “ENRICHMENT” PROGRAM ON THE BEHAVIOR OF INSTITUTIONALIZED PROFOUNDLY RETARDED CHILDREN

This study determined the effects of procedures designed to “enrich” the physical and social environment of an institutional ward on the “adaptive” and “maladaptive” child, adult, self, and object-directed behaviors of five profoundly retarded ambulatory females. Behavior observed in two treatment conditions, an environment “enriched” with toys and objects and an “enriched” environment coupled with differential reinforcement of adaptive behavior, was compared to behavior occurring in corresponding baseline or “austere” conditions and during a period of noncontingent reinforcement. The results generally revealed: (1) little change in adaptive and maladaptive child and adult-directed behavior across conditions, (2) an overall higher incidence of adaptive object-directed behavior and reduced self-directed maladaptive behavior in each treatment condition from that observed in corresponding control conditions, and (3) the use of an “enriched” environment and differential reinforcement of adaptive behavior resulted in maladaptive self-directed behavior being reduced and adaptive object-directed behavior being increased beyond that observed in the “enriched” environment alone. These behavioral gains were largely maintained during a follow-up condition by continuing the “enriched” environment and transferring the responsibility for differential reinforcement to direct-care staff.     

INDUSTRIAL SAFETY HAZARD REDUCTION THROUGH PERFORMANCE FEEDBACK

A “feedback package” system, designed to prevent occupational accidents and to fit directly into the normal operations of an industrial organization, was analyzed. Eighteen hazardous conditions in six production departments were assessed during seven observation sessions over a 12-week period, plus four follow-up observations over 4 months. The “feedback package” was presented in multiple baseline fashion, across subjects (department supervisors). It consisted of presenting the supervisor with copies of observational data, accompanied by a note which congratulated good practices and suggested ways for improving safety conditions, along with occasional comments from a senior executive. The results indicated that during the feedback phase, hazard rates were lower and less variable than during the baseline phase. Baseline data were highly variable with peaks ranging from 20 to 55 hazards per department. Following intervention, hazard frequencies dropped by 60%, averaged across departments, with decreases ranging from 29% to 88%. During treatment, data stabilized, with the highest frequency reaching 33. A modified feedback system was implemented by the organization following termination of the study, validating the assumption that such a system would tend to maintain.     

LARGE-SCALE REDUCTIONS IN SPEEDING AND ACCIDENTS IN CANADA AND ISRAEL: A BEHAVIORAL ECOLOGICAL PERSPECTIVE

We assessed the effects of posted feedback and warning ticket programs on speeding and accidents in two cities. In Experiment 1, speeding feedback signs were effective even when 10 were used in Dartmouth, Nova Scotia, and reductions in speeding were associated with reductions in accidents. The effectiveness of the signs was correlated with the number of intersections and residences within 0.5 km beyond them, and the signs had no effect on untreated streets. In Experiment 2, posted feedback and a warning program reduced speeding and accidents on 14 streets in Haifa, Israel.