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.     

Distractor clustering enhances detection speed and accuracy during selective listening

The effects of distractor clustering on target detection were examined in two experiments in which subjects attended to binaural tone bursts of one frequency while ignoring distracting tones of two competing frequencies. The subjects pressed a button in response to occasional target tones of longer duration (Experiment 1) or increased loudness (Experiment 2). In evenly spaced conditions, attended and distractor frequencies differed by 6 and 12 semitones, respectively (e.g., 2096-Hz targets vs. 1482- and 1048-Hz distractors). In clustered conditions, distractor frequencies were grouped; attended tones differed from the distractors by 6 and 7 semitones, respectively (e.g., 2096-Hz targets vs. 1482- and 1400-Hz distractors). The tones were presented in randomized sequences at fixed or random stimulus onset asynchronies (SOAs). In both experiments, clustering of the unattended frequencies improved the detectability of targets and speeded target reaction times, Similar effects were found at fixed and variable SO As. Results from the analysis of stimulus sequence suggest that clustering improved performance primarily by reducing the interference caused by distractors that immediately preceded the target.     

Linguistic Phenomena and Language Selection in the REM Dreams of German-English Bilinguals

Sixteen German-English bilinguals were studied in a sleep laboratory for four nonconsecutive nights each. Half were native English speakers living in Zürich, and half native German speakers living in Atlanta. Presleep thought samples were solicited each evening and REM dream reports each night; subjects judged the waking appropriateness of their imagined speech and language phenomena, and also identified waking sources of their dream imagery, the following mornings. Incidences of dreaming and of speech therein generally were similar to those of monolinguals. Whether sessions were conducted in German (two nights) or English (two nights) did directly influence language selection in subjects' dreams. Judged appropriateness of language selection to imagined events was very high for thought samples, and high for REM dreams. Sources for thought samples were generally consonant with the language dominant at study site; for REM dreams this relationship was considerably weaker. Judged waking appropriateness to imagined situations was more strongly related to language selection than was the language reference of the supposed sources of those situations.     

Mental Arithmetic: A Componential Analysis of Speed-of-Processing Across Monolingual,Weak Bilingual,and Strong Bilingual Adults

Two experiments compared rates of solving simple and complex addition and multiplication problems in groups of speakers of French or English in Experiment 1 (n = 35) and Spanish or English in Experiment 2 (n = 84). Subjects were divided into groups of English unilinguals, weak bilinguals, and strong bilinguals according to their performance on a naming task. In both experiments, simple problems consisted of two single-digit numbers. At least three single-digit numbers were used for complex problems in Experiment 1 and double-digit numbers in Experiment 2. Mean solution times, particularly for complex problems, were lowest for the monolingual group, followed in turn by the weak bilingual and strong bilingual groups, but these differences were not statistically reliable in either experiment. In Experiment 2, however, componential analyses of solution times indicated that strong bilingual subjects were slower at executing the carry operation when solving complex problems, relative to the two remaining groups. Results were interpreted in terms of the relationship between bilingualism and the representation and processing of numerical information.     

Parent and Teacher Ratings in the Assessment and Prediction of Antisocial and Delinquent Behaviors

ABSTRACT Subjects consisted of a sample of two cohorts of approximately 100 boys each whose behaviors were rated by their parents and teachers. Criterion variables included antisocial behavior, based on parent, child, teacher, and interviewer reports, and delinquency, based on parent and child reports in addition to cumulative arrest data taken from juvenile court records. The data suggest that mothers are focused on the daily, irritating behaviors of their sons. Teachers, on the other hand, appear to focus on a relatively small number of items (e.g., child physically attacks others, associates with deviant peers), and thereby provide ratings that are better predictors of delinquency and arrest. When the mothers' ratings were constrained to include only items that were salient for teachers, their predictive validity coefficients approached the magnitude of the teacher coefficients.     

A Coming-of-Age for Research on Interpersonal Perception

ABSTRACT Research on accuracy and consensus in interpersonal perception has become a major topic in the social sciences. Key methodological issues in this research are research design, statistical measures of agreement, unit of analysis, and data aggregation. I discuss the twelve articles devoted to these topics in this special issue in terms of moderators of agreement, the weighted average model of consensus and accuracy (Kenny, 1991), and methodological innovations.     

What is a difficult mental health case? An empirical study of relationships among domain variables

A difficult case in psychotherapy can be defined in many ways. This study proposes a model for that definition, in which three domains (patient characteristics, case characteristics, and therapist characteristics) are considered to impact on that definition. A total of 264 professionals received a questionnaire to assess the relative importance of a series of variables within and across these domains. Wilcoxon Matched-Pairs Signed-Ranks tests indicated that patient characteristics were considered more important than therapist or case characteristics in defining a difficult case. Case characteristics were considered more important than therapist characteristics. Pearson correlations, however, suggested that the three domains in the model are related. Correlations (for years of experience) and Kruskal-Wallis one-way ANOVA for ranks (for professions) also indicated that participants were able to identify variables within domains as important in that definition regardless of years of experience or professions. Across domains, the most important variables included the motivation of the client (a patient characteristic), dropout/attrition and multiple diagnoses (case characteristics), and the degree of therapist-client racial similarity (a therapist characteristic).     

Ingroup Versus Outgroup Perceptions of the Characteristics of High-Risk Youth: Negative Stereotyping1

Adolescents tend to categorize themselves and their peers into discrete ingroups and outgroups. A comparison of ingroup versus outgroup perceptions of the characteristics of high-risk youth was investigated. Based on current stereotype research, we examined the perspective that outgroup members would hold a more extreme stereotype of high-risk youth compared to the perceptions of ingroup members. A total of 955 7th- and 10th-grade southern California adolescents completed a questionnaire regarding the characteristics of their own peer group and a high-risk group. Support was obtained for an extremity of judgement effect. Outgroup youth perceived that their high-risk peers engaged in fewer school and nonschool low-risk activities, more high-risk activities, and greater drug use than did ingroup members. Outgroup members also held perceptions of high-risk youth as less likely to hold a white-collar job than did the ingroup members. The perceptions that adolescents have of these groups may play major roles in their own social behavior. The implications of these results for future tobacco use prevention programs are considered.     

The Influence of Goal Orientation on Task Performance: A Substantively Meaningful Suppressor Variable1

The present study investigated the relationship between performance goal orientation and performance on a complex task. It was hypothesized that cognitive interference would mediate this relationship. In addition, it was hypothesized that cognitive ability would moderate the relationship between cognitive interference and task performance. A three-variable suppressor relationship indicated that, although the direct effect of performance goal orientation on performance was one that produced better performance, the indirect effect of performance goal orientation indicated that performance orientations were associated with increases in cognitive interference, and these increases in cognitive interference were associated with poorer performance. Thus, the beneficial aspect of performance goal orientation (i. e., the direct effect) was counterbalanced by the dysfunctional aspects of performance goal orientation (i. e., the associated increase in cognitive interference). Support was also found for the proposed moderation of ability on the cognitive interference-task performance relationship for final, but not initial performance. The results are interpreted in light of recent discussions regarding the influence of goal orientation on task performance and cognitive interference.