A comparison of the effects of partial reinforcement schedules using a within-subject serial autoshaping procedure

Three experiments, each using a single group of pigeons, are reported. In Experiment 1 subjects were initially trained with two stimuli, one of which was always followed by food, the other being reinforced according to a 50% partial reinforcement schedule. Subsequently a serial procedure was adopted in which an additional stimulus, C, was consistently followed by the partially reinforced CS. A second additional stimulus, A, was followed on half of its occurrences by the continuously reinforced CS, its remaining presentations being followed by nothing. The rate of autoshaped keypecking was substantially greater during A than during C. In the remaining experiments subjects received first-order conditioning with a single stimulus that was either partially (Experiment 2) or continuously (Experiment 3) reinforced. The stimuli A and C were then again introduced for serial autoshaping. Stimulus A was occasionally paired with the CS and occasionally followed by nothing, whereas stimulus C was always followed by the CS. As in Experiment 1, the rate of responding during A was greater than during C. It is proposed that one influence on the rate of autoshaped keypecking during a CS is the accuracy with which the immediate consequences of that CS are predicted.     

ILLUSTRATING FEMINIST THEORY

Feminist theory holds that many of the pathological behaviors observed in patients result from their position in the social hierarchy. The goals of the demonstration detailed in this article are to show the impact of current gender roles on the psychological well-being of women and men and to generate understanding and discussion of the problems that relative status can create in the therapeutic relationship. This teaching demonstration draws parallels between the Zimbardo (1971) prison experiment and the impact that assignment to low-and high-power roles can have on the psychological health of women and men. Students are asked to rate men and women on some of the diagnostic criteria that the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994) associates with Axis I and II diagnoses. The students watch a video of Zimbardo's prison study and then rate the prisoners and guards. This demonstration provides another explanation for gender patterns in psychopathology by demonstrating that psychologically healthy White males will develop different patterns of psychopathology depending on whether they are placed in a dominant or subordinate role. When placed in the subordinate role, they exhibit behaviors typically seen in women clients; when placed in a dominant role they exhibit behaviors commonly associated with male clients. This exercise demonstrates the unhealthy nature of the gender roles for both women and men.     

A longitudinal study of pain sensitivity and blood pressure in adolescent boys: results from a 5-year follow-up.

A growing literature has observed a significant reduction in pain sensitivity among hypertensive animals and humans. It is uncertain whether a reduced sensitivity to pain can be observed in nonnotensive individuals who go on to develop high blood pressure. Blood pressure (BP) was reassessed in one hundred fifteen 19-year-old boys initially tested at age 14, when they were also presented with a pain stimulus (mechanical finger pressure). Hierarchical regression analyses indicated that information regarding pain tolerance improved prediction of changes in systolic and diastolic blood pressure beyond that afforded by differences in BP at age 14, parental history of hypertension, and body mass index. These analyses suggest that pain sensitivity may be associated with physiological processes involved in the development of sustained high blood pressure.     

The effects of self‐explaining when learning with text or diagrams

Self‐explaining is an effective metacognitive strategy that can help learners develop deeper understanding of the material they study. This experiment explored if the format of material (i.e., text or diagrams) influences the self‐explanation effect. Twenty subjects were presented with information about the human circulatory system and prompted to self‐explain; 10 received this information in text and 10 in diagrams. Results showed that students given diagrams performed significantly better on post‐tests than students given text. Diagrams students also generated significantly more self‐explanations that text students. Furthermore, the benefits of self‐explaining were much greater in the diagrams condition. To discover why diagrams can promote the self‐explanation effect, results are interpreted with reference to the multiple differences in the semantic, cognitive and affective properties of the texts and diagrams studied.     

Signification et signifiance

Sans résumé