Potentiation of the pressor response to stress by tolbutamide in dogs

Tolbutamide has previously been shown to amplify the pressor effects of “exogenous” catecholamines in conscious dogs, possibly due to sensitization of the α₁-adrenoreceptor-mediated vasoconstriction. The objective of this study was to examine if tolbutamide also amplifies the pressor effects of “endogenous” catecholamines released during psychological stress (classical Pavlovian aversive conditioning). Experiments were conducted in β-adrenoreceptor-blocked (propranolol, 1 mg/kg, i.v.) conscious dogs (n=4) trained in classical aversive conditioning. Conditioning was accomplished by following a tone (CS+) with a 1/2 second shock; another tone (CS-) was not followed by any shock and served as control. With saline pretreatment, aversive conditioning (i.e., CS+) increased mean arterial pressure (MAP) only by approximately 4.7% when compared to CS-, whereas with tolbutamide (45 mg/kg, i.v.) pretreatment, the increase in MAP induced by CS+ beyond what was induced by the CS- (approximately 6.2%) was significantly (p<0.05) larger than that with saline pretreatment. In isolated canine femoral arterial segments (n=4), the vasoconstrictor effect of phenylephrine (an α₁-agonist) at 5×10^?6M (which was the EC₅₀ value) was amplified by 2×10^?2M of tolbutamide from 54.0±2.0% to 66.9±2.1%. In conclusion, tolbutamide amplifies the pressor effects of “endogenous” catecholamines in conscious dogs, possibly by sensitization of the α₁-adrenoreceptor-mediated vasoconstriction. This mechanism of action is novel and has not been reported with other agents.     

Some hypotheses concerning the evolution of polysemous words

The evolution of polysemous words is examined in three studies. Study 1 indicates that older words are more polysemous than recent words, and that frequently used words are more polysemous than infrequently used words. These effects were replicated, controlling for word concreteness (Study 2) and evaluation (Study 3), using two other samples of words. If words evolve additional meanings through metaphor (MacCormac, 1985), then variables (such as concreteness and evaluation) that play a role in metaphor may mediate the evolution of polysemy. The correlation between concreteness and polysemy was negligible (Study 2). As hypothesized, evaluation is a significant predictor of polysemy: Negative words are more polysemous than positive words, and relatively neutral words are more polysemous than evaluatively extreme words. These findings are consistent with the notion that polysemous words evolve, in part, through metaphor.     

Extensionality, underdetermination and indeterminacy

I am grateful to Burton Dreben, Warren Goldfarb, Don Gustafson, Jim Higginbotham, Jerrold Katz, Joe Levine, Ted Morris, Nick Pappas, Hilary Putnam, Georges Rey and Bob Richardson for helpful discussions and comments on the issues discussed in this paper. Also I thank an anonymous reviewer for Erkenntnis for helpful comments.     

Late Adolescents' Experiences With and Attitudes Toward Videogames1

A total of 229 late adolescents (a large majority 15 to 19 years of age) completed a questionnaire that assesses a broad range of videogame-relevant experiences, preferences, and attitudes. Videogame playing was found to be a more popular, and a more highly regarded, activity among males than females. Gender differences were also found in participants' ratings of their motivations for playing videogames, their evaluations of particular characteristics of videogames, and their selection of their “most favorite” videogame. The differences between frequent and infrequent videogame players appeared to be limited to differences in the extent to which videogame playing is pursued and evaluated as a positive leisure activity, rather than reflecting broad differences in interest or personality. Some relations were found between participants' self-reported personality characteristics (i.e., self-esteem, empathy, conscientiousness, and introversion) and their attitudes toward videogames.     

Positive Psychological States in the Daily Life of a Sample of Working Women

This study of a sample of working women investigated where positive experiences were derived from in everyday life, focusing on the domains of work and nonwork (leisure). It examined how aspects of the situation, in terms of principal environmental influences in work and leisure, and the person, in terms of locus of control, were associated with positive subjective states and psychological well-being. The study employed questionnaires and also the experience sampling method. The results showed that both work and leisure were important for positive psychological states and that internal locus of control was associated with greater enjoyment, interest, feelings of immediate control, intrinsic motivation, life satisfaction, and affective well-being and a number of principal environmental influences.     

THE CASE FOR THE PHILOSOPHY OF CHEMISTRY

The philosophy of chemistry has been sadly neglected by most contempory literature in the philosophy of science. This paper argues that this neglect has been unfortunate and that there is much to be learned from paying greater philosophical attention to the set of issues defined by the philosophy of chemistry. The potential contribution of this field to such current topics as reduction, laws, explanation, and supervenience is explored, as are possible applications of insights gained by such study to the philosophy of mind and the philosophy of social science.     

Enhancing Classroom Performance: A Review of Reinforcement Schedules

During the past decade the application of elementary principles of behavior have become a standard in the classroom teacher's repertoire of behavior change strategies. Unfortunately, the application of more advanced principles of behavior derived through basic behavioral research lies as an untapped resource for classroom teachers. Nowhere is this more apparent than in the use of systematic procedures to deliver reinforcers to enhance academic performance. In this paper we provide educators with information on the use of reinforcement schedules in academic settings. Various schedules of reinforcement are presented along with examples of their application in applied settings.     

Judging a book by its cover: Interpretative effects of content on problem-solving transfer

We examine how cover stories of isomorphic problems affect transfer. Existing models posit that people retain content in problem representations and that similarities and differences between the “undeleted” cover stories might interfere with recognition of structural similarities.We propose that cover stories can affect transfer in another way—by inducing semantic knowledge that modifies problem structures. Two experiments examined how people represent and solve permutation problems dealing with random assignment of elements from one set to elements from another set. Although the problems were structurally isomorphic, cover stories involving different pairs of element sets led subjects to abstract different “interpreted structures.” Problems involving objects and people (e.g., prizes and students) led subjects to abstract an asymmetric structure (“get”) and problems involving similar sets of people (e.g., doctors and doctors) led subjects to abstract a symmetric structure (“pair”). Transfer was mediated by similarities and differences between the interpreted structures of the learned and the novel problems.