Sensitivity to reinforcement in concurrent arithmetic and exponential schedules

The generalized matching law states that the logarithm of the ratio of responses emitted or time spent responding in concurrent variable-interval schedules is a linear function of the logarithm of the ratio of reinforcements obtained. The slope of this relation, sensitivity to reinforcement, varies about 1.0 but has been shown to be different when obtained in different laboratories. The present paper analyzed the results from 18 experiments on concurrent variable-interval schedule performance and showed that response-allocation sensitivity to reinforcement was significantly smaller when arithmetic, rather than exponential, progressions were used to produce variable-interval schedules. There were no differences in time-allocation sensitivity between the two methods of constructing variable-interval schedules. Since the two laboratories have consistently used different methods for constructing variable-interval schedules, the differences in obtained sensitivities to reinforcement are explained. The reanalysis suggests that animals may be sensitive to differences in the distribution of reinforcements in time.     

Sex differences in spatial ability and spatial activities

Explanations of sex-related differences in spatial ability emphasizing the role of sex-differentiated experience have not been supported by direct measurement of spatial activities during adolescence, the period when these differences seem to increase. The present research involved development of a scale to measure the spatial experience of adolescents and adults. In Study 1, a list, as complete as possible of adolescent activities was compiled and given to undergraduate judges for ratings of involvement of spatial skills and sex-typing. Judges also indicated whether they had participated in each activity. Activities considered spatial by 75% or more of the judges were used to develop a spatial experience questionnaire. Judgments of the spatial nature of tasks were positively correlated with judged masculinity and with greater male than female participation. In Study 2, participation in spatial activities by undergraduates was correlated with spatial ability as measured by the Differential Aptitude Test. The activity questionnaire should prove useful in studying the development of spatial ability in adolescents and adults.     

The Pareto Argument and Inequality

The Pareto argument for inequality holds that any change from a position of equality to one of inequality is justified so long as everyone benefits from the change. G.A. Cohen criticizes this argument (which he attributes to Rawls) on the ground that changes can normally be found which preserve both equality and Pareto-efficiency. However, this does not resolve the basic conflict between the two desiderata . Strong egalitarians hold that Pareto changes are not for the better if they increase inequality too greatly. Thus if the Pareto argument holds, then strong egalitarianism is unsustainable. I argue that egalitarians need not be troubled by the Pareto argument for inequality. The Pareto criterion would not be widely accepted unless it takes account of moral harms; but if it does take account of moral harms then there is no reason to doubt that egalitarian concerns can be incorporated into the Pareto argument.
email : p.shaw@philosophy.arts.gla.ac.uk     

Social competence and conduct problems in young children: issues in assessment

Examined the differences in various facets of social competence in 2 groups of young children (ages 4-7 years)--a clinic-referred group of aggressive children (N = 60) diagnosed with oppositional defiant disorder or conduct problems and a matched comparison group of typically developing children (N = 60). Four aspects of social competence were assessed: social information processing, actual observations of conflict management skills and social play interactions during peer interactions, positive social interactions with mothers and fathers at home, and teacher reports of social competence. The social information processing assessed included problem-solving skills (hypothetical skills as demonstrated on a social problem-solving test), self-perceptions (child's awareness of his or her own social self and feelings of loneliness), perceptions of others (attributions), and perceptions of others' attitudes toward oneself. To determine the construct validity of various means of assessing child social competence, we correlated children's social information processing measures with parent and teacher reports of social adjustment and with actual observations of interactions during peer play and at home with parents. Results comparing the 2 groups suggest that young children with conduct problems have deficits in their social information processing awareness or interpretation of social cues--they overestimate their own social competence and misattribute hostile intent to others. Tests of cognitive problem solving and observations of peer play interactions indicated that the children with conduct problems had significantly fewer positive problem-solving strategies and positive social skills, more negative conflict management strategies, and delayed play skills with peers than the comparison children. Correlation analyses indicated significant correlations between children's negative attributions and the ratio of positive to negative problem-solving strategies with observations of peer play interactions.     

Trainee teachers' opinions about suicide

In response to the rising rate of youth suicide, interested parties—both overseas and in Australia—have examined various methods of suicide prevention. One popular approach has been to base prevention within secondary-school communities by equipping staff, especially teachers, to identify and appropriately intervene with at-risk youth. The attitudes toward suicide of trainee teachers from a large metropolitan university were examined. It was found that they held complex opinions about suicide. While endorsing the metaphor representing suicide as a cry for help, they also perceived the communicative intent of suicide as being primarily manipulative in nature. These results are discussed with reference to training and support of teachers by counsellors in secondary-school settings.     

Monthly fluctuation in task concentration in female college students.

50 university women with consistent and rhythmic menstrual cycles were given Golden's version of the Stroop color-word test to evaluate their concentration accuracy. 50 male undergraduates were also tested as a control sample. The participants took the Stroop test every seven days for four consecutive weeks to allow examination of whether change in the color and word naming activity occurred. A split-plot analysis of the variance of the scores gave a significant difference for the sequence in which the tests were taken, the measures recited during the testing, and the sex of the respondent. When the values for the women were ordered to correspond to stages of their menstrual cycle, the over-all mean accuracy rose slowly to midcycle, then dropped as menses approached. This supports the hypothesis that the women's concentration was at the lowest level during the latter part of the monthly cycle. Women scored significantly higher on the color and word naming task on the Stroop test than men.     

Psychosocial predictors of gay men's AIDS risk-reduction behavior.

Used psychosocial variables derived from the health belief model (Rosenstock, 1974), Bandura's (1986) self-efficacy framework, and protection motivation theory (Rogers, 1984) to predict self-reported AIDS risk-reduction behaviors in a sample of 389 homosexual men who participated in the Multicenter AIDS Cohort Study in Los Angeles and who knew their HIV antibody status. Hierarchical multiple regression analyses showed that self-efficacy, perceived risk, response efficacy, and prior sexual behavior accounted for approximately 70% of the variance in the total number of sexual partners and the number of anonymous partners over a 6-month interval, controlling for demographic variables, HIV antibody status, and presence of a primary partner. A logistic regression analysis showed that barriers to change predicted increased unprotected anal receptive intercourse over a 6-month interval, controlling for prior behavior. The relation of health beliefs to risk-reduction behavior was substantially different for HIV-seropositive men without primary partners than for other groups of gay men. Implications for interventions are discussed.     

The Field of Disasters and Disaster Stress

The literature on disasters - including the contributions to the present symposium - refers to a wide range of victim groups and very different kinds of disasters. There is a need for a classificatory system which draws the different studies together. Disasters may be natural, technological or human, and can be subdivided into categories relating to earth, fire, water/liquid and people. The stages in dealing with disaster include preparedness, response, recovery and mitigation. Further categorisation is necessary in terms of types of victim. A three-dimensional model for the integration of disaster studies is proposed.