IRT-stimulus contingencies in chained schedules: implications for the concept of conditioned reinforcement

Two experiments with pigeons investigated the effects of contingencies between interresponse times (IRTs) and the transitions between the components of 2- and 4-component chained schedules (Experiments 1 and 2, respectively). The probability of component transitions varied directly with the most recent (Lag 0) IRT in some experimental conditions and with the 4th (Lag 4) IRT preceding the most recent one in others. Mean component durations were constant across conditions, so the reinforcing effect of stimulus change was dissociated from that of delay to food. IRTs were longer in the Lag-0 than in the Lag-4 conditions of both experiments, thus demonstrating that stimulus change functioned as a reinforcer. In the Lag-0 conditions of Experiment 2, the Component-1 IRTs increased more than the Component-2 IRTs, which in turn increased more than the Component-3 IRTs. This finding runs counter to the conditioned-positive-reinforcement account of chained-schedule responding, which holds that the reinforcing effect of stimulus change should vary in strength as an inverse function of the delay to the unconditioned reinforcer at the end of the chain because conditioned reinforcement is due to first- or higher-order classical conditioning. Therefore, we present other possible explanations for this effect.     

Exercise is positively related to adolescents' relationships and academics.

Eighty-nine high school seniors were administered a questionnaire that gathered information on their exercise habits (ranging from rarely to daily), relationships with parents and peers, depressive tendencies, sports involvement, drug use, and academic performance. Students with a high level of exercise had better relationships with their parents (including greater intimacy and more frequent touching), were less depressed, spent more time involved in sports, used drugs less frequently, and had higher grade point averages than did students with a low level of exercise.     

The effect of stress on the linguistic generalization of bilingual individuals

Spanish-English coordinate bilinguals were subjects in a GSR linguistic conditioning experiment using strong and mild buzzer conditions and spoken stimuli. Each subject was randomly assigned to one of two lists of words and one of two levels of buzzer sounds. A Spanish word from the Spanish list and an English word from the English list functioned as a conditioned word (CS). The lists were Spanish and English words related semantically and phonemically and unrelated to the CS. Generalization was studied under conscious and unconscious conditions. We found that both buzzer conditions resulted in significantly greater GSR responses to semantic and phonemic words than to words unrelated to the CS. Generalization to semantic words was not significantly greater than to phonemic words. There was a tendency toward greater phonemic than semantic generalization in the strong buzzer condition. The opposite was observed regarding the mild buzzer. The results were the same in both lists and languages. Under a conscious and unstressful condition, generalization to semantic words was found to be more prominent than to phonemic words. This suggests that under normal condition semantic generalization is mediated by conscious cognition. We concluded that strong emotion produces an increase in phonemic, as compared to semantic, generalization in both languages. Hence, primitivization of the subjects' cognitive and linguistic functioning is assumed to have occurred. These results are important in understanding the deleterious effect that stressful situations may have on linguistic functioning and cognition in bilinguals.     

Linking empirically based theory and evaluation: The family bereavement program

Conclusion We have illustrated how our small theory (Lipsey, 1990) of bereavement guided the development and evaluation of a preventive intervention for bereaved children. Our small theory, based on prior empirical research, enabled us to identify family processes that appeared to mediate the effects of parental death on child mental health. Our intervention was designed to attempt to change these processes. The evaluation of our experimental trial of the intervention assessed changes on these processes as well as the more distal mental health outcomes. The experimental trial showed some-what encouraging results, in terms of the program's ability to modify the warmth of the parent–child relationship and to decrease symptomatology in the adolescent children. We also obtained further empirical support for our underlying theoretical model. Finally, implications for redesign of the program were derived from assessing the adequacy of the program components to change each of the mediators in the theoretical model.Support for this research was provided by NIMH grant P5OMH39246 which is gratefully acknowledged. David R. Pillow is now at Western Psychiatric Institute, Pittsburgh; Fred Rogosch is at the University of Rochester; Janette Beals is now at University of Colorado Health Sciences Center; Kim D. Reynolds is now at the University of Alabama, Birmingham; Carl Kallgren is now at the Pennsylvania State University, at Erie; and Rafael Ramirez is now at the University of Puerto Rico.     

Definability of directly indecomposable congruence modular algebras

It is proved that the directly indecomposable algebras in a congruence modular equational class form a first-order class provided that fulfils some two natural assumptions.Research supported by CONICOR and SECYT (UNC).Presented by W. Dziobiak     

Contemporary Definitions of Suicidal Behavior: A Systematic Literature Review

To address the lack of comparability around the world, we conducted a systematic review of existing definitions of suicide and suicidal behaviors. In the literature, four key features appear to cover the vast majority of concepts underpinning definitions: agency, knowledge of a potential fatal outcome, intent, and outcome. Intent and outcome appear to be the most consensual features of definitions of suicide, albeit revealing interesting conceptual variations. The four key features could be used to devise a research tool able to explore the meanings of suicide across different countries and different cultures.     

Prenatal depression effects on the fetus and newborn: a review

A review of research on prenatal depression effects on the fetus and newborn suggests that they experience prenatal, perinatal and postnatal complications. Fetal activity is elevated, prenatal growth is delayed, and prematurity and low birthweight occur more often. Newborns of depressed mothers then show a biochemical/physiological profile that mimics their mothers' prenatal biochemical/physiological profile including elevated cortisol, lower levels of dopamine and serotonin, greater relative right frontal EEG activation and lower vagal tone. Elevated prenatal maternal cortisol is the strongest predictor of these neonatal outcomes. Moderate pressure massage can alleviate these effects including reducing prematurity.