Chronic corticosterone-induced deterioration in rat behaviour is not paralleled by changes in hippocampal NF-kappaB-activation

We investigated whether long-lasting stress induced by chronic glucocorticoid (GC) exposure affects activation of brain NF-kappaB and whether these changes are related to functional deterioration and structural changes in the rat hippocampus. Psychometric investigations were conducted using a holeboard test system in 28 one-year-old male Wistar rats. Thereafter, rats were divided into three groups for daily administration of 10 mg corticosterone (treatment) or sesame oil (placebo = sham control for effects of the vehicle) for 60 days. Additional control rats did not receive any treatment or handling until the end of the experiment. Behavioural and cognitive changes were tested again in the holeboard system. Rat body weights and corticosterone concentrations in plasma, hippocampus and urine were determined and adrenal glands were investigated histopathologically. Hippocampal concentrations of corticosterone, NF-kappaB and I-kappaBalpha were determined using RIA, EMSA and Western blotting techniques, respectively. Structural changes in rat hippocampus were measured using magnetic resonance imaging techniques. High peripheral corticosterone concentrations after chronic treatment led to significant reductions in rat body weight. Significant atrophy of both adrenal glands with marked histological deterioration was detected. Furthermore, an increase in hippocampal corticosterone concentrations was observed after chronic administration. Chronic corticosterone treatment also significantly altered behaviour and working and reference memory capacity without changing hippocampal structure. Daily injections of sesame oil in the placebo group, however, were also sufficient to reduce the pellet-finding time. However, neither in the corticosterone group nor in the placebo group were behavioural changes paralleled by significant changes in brain NF-kappaB activation and I-kappaBalpha expression. Thus, cognitive alterations in rats seen after chronic corticosterone exposure are not paralleled by hippocampal NF-kappaB modulation.     

Madness and Disability in Contemporary Chinese Film

This article draws on recent research in the medical humanities to analyze two contemporary Chinese films: Zhang Yuan's Sons (1996) and Zhou Xiaowen's The Common People (1998). By portraying psychic and physical anguish in ways that refuse to divorce biology from culture, such films offer rare moral dialogues on biomedical issues and contribute a cross-cultural perspective invaluable to the task of responding to illness and suffering.     

Physiological and behavioral parameters of infants' categorization: changes in heart rate and duration of examining across trials

This report investigates the relations between duration of examining and heart rate (HR) across several trials of an object-examination task. A total of N= 20 11-month-olds were familiarized with a sequence of 10 different exemplars from the same global category (animals or furniture) before they received an exemplar from the contrasting category at test. Consistent with previous findings, HR was lower during states of focused attention (i.e. examining) than during states of casual attention (i.e. looking) or non-looking. Over the familiarization trials, examining stayed about the same, while mean HR increased. At test, examining increased and mean HR decreased, indicating that infants focused their attention on the out-of-category object. Psychophysiological and behavioral measures of attention were systematically related over trials, suggesting that heart rate provides a suitable objective measure to study infants' categorization performance in object-examination tasks.     

The role of individual differences in the accuracy of confidence judgments

Generally, self-assessment of accuracy in the cognitive domain produces overconfidence, whereas self-assessment of visual perceptual judgments results in underconfidence. Despite contrary empirical evidence, in models attempting to explain those phenomena, individual differences have often been disregarded. The authors report on 2 studies in which that shortcoming was addressed. In Experiment 1, participants (N= 520) completed a large number of cognitive-ability tests. Results indicated that individual differences provide a meaningful source of overconfidence and that a metacognitive trait might mediate that effect. In further analysis, there was only a relatively small correlation between test accuracy and confidence bias. In Experiment 2 (N = 107 participants), both perceptual and cognitive ability tests were included, along with measures of personality. Results again indicated the presence of a confidence factor that transcended the nature of the testing vehicle. Furthermore, a small relationship was found between that factor and some self-reported personality measures. Thus, personality traits and cognitive ability appeared to play only a small role in determining the accuracy of self-assessment. Collectively, the present results suggest that there are multiple causes of miscalibration, which current models of over- and underconfidence fail to encompass.     

Decision Pattern Analysis as a General Framework for Studying Individual Differences in Decision Making

This paper investigated decision pattern analysis (DPA) as a general and standard framework for studying individuals' consistent decision making behavior within and between contexts. DPA classifies decisions on the basis of judgement accuracy and the goal orientation of the decided‐upon action. Over repeated decisions, patterns of individuals' decision behavior are described by five variables: competence, optimality, recklessness, hesitancy and decisiveness. A fictitious medical decision making test and three standard cognitive ability tests (extended with confidence ratings and a ‘submit answer for marking’ decision) were used to investigate the psychometric properties of these DPA variables. Internal consistency of the decision patterns ranged from good to excellent. Convergent validity was assessed via cognitive abilities, metacognitive confidence and a control criterion imposed on confidence that determines the decision to be made: the point of sufficient certainty. Personality variables were included to assess discriminant validity. As hypothesised, cognitive abilities showed positive correlations with competence and optimality. High confidence, low points of sufficient certainty and a greater discrepancy between them were associated with higher decisiveness and recklessness, and lower hesitancy. Personality measures showed mixed and generally weak correlations with the DPA variables. These convergent and discriminant results also held after controlling for all variables in regression. The results provide preliminary psychometric support for DPA as a general framework of behavioral decision making. DPA has the potential to be exploited in many contexts for uses that, to date, have been unachievable in a psychometrically valid manner. Copyright © 2015 John Wiley & Sons, Ltd.     

A cognitively-gated place? The role of need for closure in a biased perception of the place’s past

Biased memory of the past is often a starting point for intergroup conflicts. In three correlational studies, we examined the relationship between need for closure (NFC) and historical ethnocentric bias, a tendency to overestimate the role of one’s ethnic group in the multicultural history of the city of residence. In addition, we checked whether this relationship would be mediated by an individual preference for essentialist places. We found that higher NFC was related to increased historical ethnocentric bias. Moreover, this relation was mediated by preference for an essentialist type of a place. Our results may contribute to understanding the role of individual differences and preferred type of place in shaping a biased representation of the past. Furthermore, our research findings point to the importance of raising awareness of the multicultural past among high NFC individuals.

     

Nuestra culpa: collective guilt and shame as predictors of reparation for historical wrongdoing

Three studies examined the hypothesis that collective guilt and shame have different consequences for reparation. In 2 longitudinal studies, the ingroup was nonindigenous Chileans (Study 1: N = 124/120, lag = 8 weeks; Study 2: N = 247/137, lag = 6 months), and the outgroup was Chile's largest indigenous group, the Mapuche. In both studies, it was found that collective guilt predicted reparation attitudes longitudinally. Collective shame had only cross-sectional associations with reparation and no direct longitudinal effects. In Study 2, collective shame moderated the longitudinal effects of collective guilt such that the effects of guilt were stronger for low-shame respondents. In Study 3 (N = 193 nonindigenous Chileans), the cross-sectional relationships among guilt, shame, and reparation attitudes were replicated. The relationship between shame and reparation attitudes was mediated by a desire to improve the ingroup's reputation.     

The role of functional information for infant categorization

This report examines whether knowledge about function influences the formation of artifact categories in 11-12- month old infants. Using an object-examination task, a set of artificial stimuli was presented that could either be grouped according to overall similarity or according to similarity in one functionally relevant part. Experiment 1 revealed that infants categorized the objects according to overall similarity but not part similarity under control conditions. Experiment 2 showed that after having seen the experimenter demonstrating the functional use of the critical part, infants later categorized the stimuli according to part similarity. When the same actions were performed without producing any effect, infants failed to categorize according to the critical part. This set of findings suggests that 11-12-month old infants use functional information as a cue to categorization.     

Collective decision making reduces metacognitive control and increases error rates,particularly for overconfident individuals

This research aimed to investigate the changes in judgment accuracy, confidence, control thresholds, and decision outcomes when people act in two-person groups (dyads) compared with acting individually. First, we used interacting dyads to determine the metacognitive and behavioral outcomes of collective decision making and compared them with those of individuals. Second, we examined whether these changes were related to the trait-confidence and bias of individuals working together. Using a within-person design, undergraduate psychology students (N = 116) completed a General-knowledge Test individually, then together as a dyad. Each question was accompanied by a confidence rating and a decision to bet $10 on the answer. Dyads had significantly higher confidence and lower control thresholds than individuals. They were also significantly more decisive (made more bets) and reckless (lost a higher rate of bets) than when working alone. Thus, we observed a higher rate of decision errors for groups than individuals. The results also demonstrated the important role of individual differences: Overconfident individuals became even more confident, decisive, and reckless when working together compared with less confident or underconfident individuals working together. These findings have important theoretical and applied implications for collective decision making; metacognitive bias and potentially control thresholds may be targeted to alleviate the larger error rates and guide the formation of more effective groups.     

Cause or effect: What matters? How 12‐month‐old infants learn to categorize artifacts

This paper investigates the role of cause and effect relations for infants' learning about artifacts. Two experiments tested whether 12‐month‐olds categorized a given set of unfamiliar artifacts according to overall similarity and/or according to part similarity, depending on what kind of video demonstration was presented before the start of the categorization task. In both experiments, the actions performed with objects were accompanied by interesting effects but the causal relation between object‐structure and effects was teased apart. In one video demonstration (Expt 1), the experimenter used the object part to produce some kind of effect in a causally plausible way. In another video demonstration (Expt 2), the experimenter performed similar actions with the same objects as in Expt 1, followed by the same effects as before. Importantly, however, no plausible cause–effect relation was provided this time. Only infants participating in Expt 1 categorized the set of unfamiliar objects according to part similarity. This finding suggests that 12‐month‐olds attend to the causal relation between specific object parts and their functional use when categorizing artifacts, rather than merely associating form‐characteristics with an interesting effect.