Sex differences in chronic stress effects on memory in rats

Recent studies in rodent models and in humans have shown that the status of both the gonadal and adrenal axes (hypothalamic-pituitary-gonadal, HPG and hypothalamic-pituitary-adrenal, HPA, respectively) can influence learning and memory function. In this article, the effects of activating the HPA axis (stress) on performance of memory tasks in rats are reviewed. More importantly, results are presented which show that chronic stress has a different impact on performance of these tasks depending upon the sex of the rat. These observations are novel and potentially important since few studies, animal or human, have utilized females as subjects in studies of the stress response. Sex differences in the effects of chronic stress on memory were investigated in rats using an object recognition task and two spatial memory tasks, radial arm maze and object location. Given the same chronic stress--21 days of restraint for 6 h each day--males were impaired in all of the memory tests while females showed enhanced performance of the spatial memory tasks and no changes in object recognition performance. Levels of neurotransmitters and metabolites were measured in brain areas important for cognition in the subjects in order to determine neural systems that may respond to stress and mediate the cognitive responses. These results show that responses of monoamine and amino acid containing neural systems may contribute to or underlie sex differences in stress effects on cognition. Stress decreased dopaminergic activity in the frontal cortex and amygdala of males but not females; whereas, in CA3 of the hippocampus, stress increased levels of 5-HT and norepinephrine in females, but not males, and increased GABA in males, but not females. Finally, a possible role for estradiol in mediating sexually differentiated responses to stress was examined. Behavioral and neurochemical evaluations in ovariectomized, stressed females, with or without estrogen replacement, suggest that sex differences in response to stress are influenced by both the organizing and activating effects of estradiol. A few, recent studies in humans, that show sexually dimorphic relationships between chronic stress and cognition, are also highlighted. These results in humans are consistent with the pattern of results in rats. Clearly, further studies are necessary to substantiate sex differences in stress effects on memory function in humans and to understand mechanisms whereby estrogen may influence the stress response in rats. Nonetheless, recent studies show sexually differentiated cognitive responses to chronic stress and underline the importance of considering the sex/gender of subjects when studying the stress response.     

The Aggression Questionnaire: a validation study in student samples

The goal of this study was to examine the psychometric properties of the Aggression Questionnaire (AQ) in Spain. The AQ is a 29-item instrument designed to measure the different dimensions of the hostility/anger/aggression construct. It consists of 4 subscales that assess: (a) anger, (b) hostility, (c) verbal aggression, and (d) physical aggression. In Study 1, reliability, construct validity, and convergent validity were evaluated in a group of 384 male and female university students. Test-retest reliability was evaluated using a group of 154 male and female university students. The results of the factor analysis were similar to the scale structure claimed for this instrument. The subscales also showed internal consistency and stability over time. The AQ and its subscales were also compared with the scales and subscales of the Spielberger State-Trait Anger Expression Inventory (STAXI), the Cook-Medley Hostility Scale (Ho), the Buss-Durkee Hostility Inventory (BDHI), and the Jenkins Activity Survey-Form H (JASE-H). The results show that the AQ evaluates some aspects of anger, such as Anger-Trait and Anger-Out, rather than other elements, such as Anger-In or Anger-State. In Study 2, two new male groups were used to evaluate the criterion validity of the AQ: 57 prison inmates and 93 university students, finding that this instrument discriminated between the scores obtained by common offenders and university students.     

Political rhetoric,immigration attitudes,and contemporary prejudice: a Mexican American dilemma

The authors examined political candidates' social stereotypes of Mexican immigrants in mainstream media accounts. From those popular themes, they formed semantic differential scales, which they administered to participants (N = 201) with 1 of 4 scenarios describing an illegal immigrant: of Mexican vs. English Canadian descent and with vs. without several parking tickets. Consistent with contemporary theories of prejudice (J. F. Dovidio & S. L. Gaertner, 1996), the participants indicated the greatest agreement with the pejorative themes when the immigrant described was of Mexican descent and had accumulated parking tickets. Psychologically, the parking tickets served as a nonethnic rationale for discriminating against that ethnic group. The authors discuss the social and public policy implications of Mexican immigration as a political phenomenon.     

US patriotism and ideologies of group dominance: a tale of asymmetry

Using a random sample (N = 405) of White and Latino Americans from Los Angeles County, the authors explored whether there is an asymmetrical relationship between U.S. patriotism and two different dimensions of social dominance orientation: group antiegalitarianism and group dominance. Although there was no evidence of asymmetry in the relationship between U.S. patriotism and group antiegalitarianism, there was evidence of consistent asymmetry in the relationship between U.S. patriotism and group dominance. Among Whites (the dominant North American ethnic group) and depending on demographic variables such as age, education, income, and gender, the greater the respondents' tendency to subordinate "inferior groups," the greater their level of U.S. patriotism. In contrast, among Latino Americans (the major subordinate group in Southern California), the opposite trend was found. Here, higher levels of group dominance orientation were associated with lower levels of U.S. patriotism. The theoretical implications of these findings are discussed.     

Self-control in honeybees

Self-control means choosing a large delayed reward over a small immediate reward; impulsiveness is its opposite. The metabolic hypothesis states that the amount of self-control across species correlates negatively with metabolic rate (Tobin & Logue, 1994). Foraging honeybees have high metabolic rates; the metabolic hypothesis would predict little self-control in bees. But foraging bees work for the longterm good of their hive, conditions that seem to require self-control. In three experiments, we gave bees the choice between (1) a sweeter delayed reward and a less sweet immediate reward and (2) a large delayed reward and a small immediate reward. Bees showed much self-control, inconsistent with the metabolic hypothesis.     

A pragmatic guideline for evaluation of social intervention

Considering the many theoretical and methodological viewpoints in the field of evaluation, a guideline was established to facilitate the evaluation of social intervention programs. For this purpose, the goals of the evaluation were taken into account: (a) planning interventions, (b) learning and continuous improvement of interventions, (c) programming policies, and (d) transformation of society. These goals will determine the perspective of the analysis selected (focusing on the evaluand or the context) and the strategies for change employed (focusing on processes or results). The elements that, according to Shadish, Cook, and Levinton (1991), constitute the theory of evaluation (evaluand, value, building of knowledge, and uses) have also been considered. The analysis of all these components led to the elaboration of a guideline to orient the practice of evaluation from a pragmatic perspective, in accordance with the demands and needs of a certain social context.     

Constructivism, the so-called semantic learning theories, and situated cognition versus the psychological learning theories

In this paper, the perspective of situated cognition, which gave rise both to the pragmatic theories and the so-called semantic theories of learning and has probably become the most representative standpoint of constructivism, is examined. We consider the claim of situated cognition to provide alternative explanations of the learning phenomenon to those of psychology and, especially, to those of the symbolic perspective, currently predominant in cognitive psychology. The level of analysis of situated cognition (i.e., global interactive systems) is considered an inappropriate approach to the problem of learning. From our analysis, it is concluded that the pragmatic theories and the so-called semantic theories of learning which originated in situated cognition can hardly be considered alternatives to the psychological learning theories, and they are unlikely to add anything of interest to the learning theory or to contribute to the improvement of our knowledge about the learning phenomenon.     

Liberalism,Abstract Individualism,and the Problem of Particular Obligations

In the following I take issue with the allegation that liberalism must inevitably be guilty of ‘abstract individualism’. I treat Michael Sandel’s well-known claim that there are ‘loyalties and convictions whose moral force consists partly in the fact that living by them is inseparable from understanding ourselves as the particular persons we are’ as representative of this widely held view. Specifically, I argue: (i) that Sandel’s account of the manner in which ‘constitutive’ loyalties function as reasons for action presupposes the possibility of there being (what I call) ‘underivable particular obligations’, but that such obligations are, in fact, a logical impossibility; and (ii) that Sandel’s account of the self as necessarily ‘encumbered’ presupposes an account of personal identity which confuses identification with definition, and which is, therefore, fundamentally flawed. For their constructive and insightful comments on an earlier draft of this paper, I owe a special debt of gratitude to the following: Clare Chambers, Roger Crisp, Cécile Fabre, Paul Kelly, David Lloyd-Thomas. Thanks also go to Res Publica’s two anonymous referees.