A new principle of pellet feeder design

Most current commercial devices dispense dry food pellets by moving the pellets horizontally toward a discharge point. Individual pellets, captured by perforations in a horizontal metal disk, are discharged one by one by stepwise rotation of the disk within the pellet reservoir. In our laboratory, where the average pellet discharge rate is some 20,000 pellets per week, feeders of this type produced occasional problems. Some were electronic; others involved failure always to capture a pellet in each perforation, particularly when the pellet supply was low. But the most common problem was an accumulation of pellet chips and dust under and around the perforated disk, which ultimately jammed the mechanism. Despite weekly cleaning and maintenance, troubles arose at least twice a month, prompting a search for a simpler pellet-feeder design which would be more reliable and require less maintenance. The present pellet feeder employs a vertical rather than horizontal design principle. It has been used extensively in operant conditioning applications for more than a year. More than 200,000 pellets have been reliably discharged from a single feeder without a breakdown. No maintenance, other than a weekly cleaning of the discharge tube, has been required.     

Health and salvation as the ethical ideal

Health and salvation are related terms, because each seeks the well-being of the whole person. When placed within the Judeo-Christian context, health as salvation can be defined as the highest good for the total human community. This good is denied to humanity through the unequal use of the world's resources, a fact underscored by the current energy crisis. Two questions must be answered: 1) Do we possess the scientific means to rectify this ethically unacceptable situation? 2) Do we desire to implement the necessary steps to change, should they be found?     

Effects of reinforcement schedules on rats' choice behavior in extinction.

The effects of reinforcement schedules on rats' choice behavior in extinction were studied. In a free-operant chamber equipped with two retractable bars, the experimental animals were trained to press the bars separately for a food reward. One bar delivered the reward on a continuous reinforcement (CRF) schedule, and the other delivered the reward on a partial reinforcement (PRF) schedule. Control animals earned the reward from both bars with the same reinforcement schedule, either a CRF or a PRF. When both bars were simultaneously available during extinction, the experimental animals responded more frequently to the CRF than to the PRF alternative, demonstrating a reversed within-subjects partial reinforcement extinction effect (PREE). A conventional between-subjects PREE was replicated in the control subjects. The results of this study were inconsistent with both Amsel's (1962, 1967) frustration hypothesis and Capaldi's (1966, 1967) sequential hypotheses.     

Situations and specific coping strategies associated with clinical and nonclinical panic attacks.

The present paper reports the results of further comparisons between clinical and nonclinical panickers. Both panic disorder patients and nonclinical panickers reported a variety of situational contexts associated with panic attacks, and differed markedly in their attempts to cope with panic. Nonclinical panickers tended to use more 'positive' coping strategies in response to panic. Conversely, one of the most commonly used and subjectively effective coping strategies reported by panic disorder patients was to escape the situation.     

Social status,cognitive ability,and educational attainment as predictors of liberal social attitudes and political trust

We examined the prospective associations between family socio-economic background, childhood intelligence (g) at age 11, educational and occupational attainment, and social attitudes at age 33 in a large (N = 8804), representative sample of the British population born in 1958. Structural equation Modeling identified a latent trait of ‘liberal social attitudes’ underlying attitude factors that are antiracist, socially liberal, and in support of gender equality. Another attitude factor—‘political trust’—was relatively independent from the latent attitude trait and has somewhat different pathways in relation to the other variables included in the analysis. There was a direct association between higher g at age 11 and more liberal social attitudes and political trust at age 33. For both men and women the association between g and liberal social attitudes was partly mediated via educational qualifications, and to a much lesser extent via adult occupational attainment. For women the association between g and political trust was partly mediated through both educational qualification and occupational attainment, and for men it was mediated mainly via occupational attainment. Men and women who had higher educational qualifications and higher occupational status tend to be more socially liberal and more trusting of the democratic political system. In terms of socio-economic background, people from less privileged families showed less political trust, but did not differ much in liberal social attitudes from those born into relatively more privileged circumstances. This study shows that social background, cognitive ability, education, and own social status influence perceptions of society.     

The effects of concurrent verbal and visual tasks on category learning

Current theories of category learning posit separate verbal and nonverbal learning systems. Past research suggests that the verbal system relies on verbal working memory and executive functioning and learns rule-defined categories; the nonverbal system does not rely on verbal working memory and learns non-rule-defined categories (E. M. Waldron & F. G. Ashby, 2001; D. Zeithamova & W. T. Maddox, 2006). However, relatively little research has explored the importance of visual working memory or visual processing for either system. The authors investigated the role of working memory (Experiment 1a and 1b), visual processing (Experiment 2), and executive functioning for each system, using a concurrent task methodology. It was found that visual tasks with high executive functioning demands and verbal tasks with high or low executive demands disrupted rule-defined learning, whereas any visual task, regardless of executive functioning demand, disrupted non-rule-defined learning. Taken together, these results confirm the importance of verbal working memory and executive functioning for the verbal system and provide new evidence for the importance of visual processing for the nonverbal system. These results help to clarify understanding of the nonverbal system and have implications for multiple systems theories of category learning (F. G. Ashby, L. A. Alfonso-Reese, A. U. Turken, & E. M. Waldron, 1998).     

Sex differences in impulsivity: a meta-analysis

Men are overrepresented in socially problematic behaviors, such as aggression and criminal behavior, which have been linked to impulsivity. Our review of impulsivity is organized around the tripartite theoretical distinction between reward hypersensitivity, punishment hyposensitivity, and inadequate effortful control. Drawing on evolutionary, criminological, developmental, and personality theories, we predicted that sex differences would be most pronounced in risky activities with men demonstrating greater sensation seeking, greater reward sensitivity, and lower punishment sensitivity. We predicted a small female advantage in effortful control. We analyzed 741 effect sizes from 277 studies, including psychometric and behavioral measures. Women were consistently more punishment sensitive (d = -0.33), but men did not show greater reward sensitivity (d = 0.01). Men showed significantly higher sensation seeking on questionnaire measures (d = 0.41) and on a behavioral risk-taking task (d = 0.36). Questionnaire measures of deficits in effortful control showed a very modest effect size in the male direction (d = 0.08). Sex differences were not found on delay discounting or executive function tasks. The results indicate a stronger sex difference in motivational rather than effortful or executive forms of behavior control. Specifically, they support evolutionary and biological theories of risk taking predicated on sex differences in punishment sensitivity. A clearer understanding of sex differences in impulsivity depends upon recognizing important distinctions between sensation seeking and impulsivity, between executive and effortful forms of control, and between impulsivity as a deficit and as a trait.     

Can we really do without self-esteem? Comment on Crocker and Park (2004)

Because self-esteem plays a central role in managing anxiety and provides a superordinate goal that organizes much human behavior, the authors conclude that it would be extremely difficult and probably impossible for people to stop pursuing self-esteem. Although they agree that investment in others' welfare may circumvent some of the negative consequences of self-esteem pursuit, the authors argue that the self-esteem implications of other-oriented behavior will inevitably be a powerful motivating force. Finally, the authors propose that self-esteem derived from self-determined standards of value may reduce defensiveness, closed-mindedness, and indifference to others, as well as promote personal growth, but they acknowledge the daunting barriers to the attainment of such self-determined bases of self-worth.