Improved Fisher z estimators for univariate random‐effects meta‐analysis of correlations

Several authors have studied or used the following estimation strategy for meta‐analysing correlations: obtain a point estimate or confidence interval for the mean Fisher z correlation, and transform this estimate to the Pearson r metric. Using the relationship between Fisher z and Pearson r random variables, I demonstrate the potential discrepancy induced by directly z‐to‐r transforming a mean correlation parameter. Point and interval estimators based on an alternative integral z‐to‐r transformation are proposed. Analytic expressions for the expectation and variance of certain meta‐analytic point estimators are also provided, as are selected moments of correlation parameters; numerical examples are included. In an application of these analytic results, the proposed point estimator outperformed its usual direct z‐to‐r counterpart and compared favourably with an estimator based on Pearson r correlations. Practical implications, extensions of the proposed estimators, and uses for the analytic results are discussed.     

Examining the Relations Among Narcissism, Impulsivity, and Self-Defeating Behaviors

ABSTRACT A recent meta-analysis ( S. Vazire & D. C. Funder, 2006 ) suggested that narcissism and impulsivity are related and that impulsivity partially accounts for the relation between narcissism and self-defeating behaviors (SDB). This research examines these hypotheses in two studies and tests a competing hypothesis that Extraversion and Agreeableness account for this relation. In Study 1 , we examined the relations among narcissism, impulsivity, and aggression. Both narcissism and impulsivity predicted aggression, but impulsivity did not mediate the narcissism–aggression relation. In Study 2 , narcissism was related to a measure of SDB and manifested divergent relations with a range of impulsivity traits from three measures. None of the impulsivity models accounted for the narcissism–SDB relation, although there were unique mediating paths for traits related to sensation and fun seeking. The domains of Extraversion and low Agreeableness successfully mediated the entire narcissism–SDB relation. We address the discrepancy between the current and meta-analytic findings.     

Meditation,mindfulness and cognitive flexibility

This study investigated the link between meditation, self-reported mindfulness and cognitive flexibility as well as other attentional functions. It compared a group of meditators experienced in mindfulness meditation with a meditation-naïve control group on measures of Stroop interference and the “d2-concentration and endurance test”. Overall the results suggest that attentional performance and cognitive flexibility are positively related to meditation practice and levels of mindfulness. Meditators performed significantly better than non-meditators on all measures of attention. Furthermore, self-reported mindfulness was higher in meditators than non-meditators and correlations with all attention measures were of moderate to high strength. This pattern of results suggests that mindfulness is intimately linked to improvements of attentional functions and cognitive flexibility. The relevance of these findings for mental balance and well-being are discussed.     

ELOPTA: A novel microcontroller-based operant device

Operant devices have been used for many years in animal behavior research, yet such devices a regenerally highly specialized and quite expensive. Although commercial models are somewhat adaptable and resilient, they are also extremely expensive and are controlled by difficult to learn proprietary software. As an alternative to commercial devices, we have designed and produced a fully functional, programmable operant device, using a PICmicro microcontroller (Microchip Technology, Inc.). The electronic operant testing apparatus (ELOPTA) is designed to deliver food when a study animal, in this case a bird, successfully depresses the correct sequence of illuminated keys. The device logs each keypress and can detect and log whenever a test animal i spositioned at the device. Data can be easily transferred to a computer and imported into any statistical analysis software. At about 3% the cost of a commercial device, ELOPTA will advance behavioral sciences, including behavioral ecology, animal learning and cognition, and ethology.     

Development of the positive–negative asymmetry effect: in‐group exclusion norm as a mediator of children's evaluations on negative attributes

Two studies were conducted that go beyond previous research by examining when and why children might show intergroup bias in the attribution of positive, but not negative traits (PNAE: the positive–negative asymmetry effect, Mummendey & Otten, 1998, European review of social psychology, Vol. 9). In Study 1 (n = 107) children completed a ‘mixed’ trait attribution task in a dichotomous group context. As predicted there was a developmental trend between 7 and 12 years of age in the PNAE. The 7‐year olds were the only age group not to show the effect. Study 1 also found a quadratic developmental trend in children's national intergroup bias. Study 2 (n = 62) replicated the developmental path of the PNAE found in Study 1 using a wider age range of 6–16 years. This study used a ‘mixed’ list of traits which were not only antonyms and a procedure that made the positive and negative trait dimensions explicitly independent. Significantly, Study 2 found in‐group exclusion norm partially mediated the development of the PNAE. These findings support an account of the positive–negative asymmetry effect based upon normative processes. Copyright © 2006 John Wiley & Sons, Ltd.     

Two Notions of Scientific Justification

Scientific claims can be assessed epistemically in either of two ways: according to scientific standards, or by means of philosophical arguments such as the no-miracle argument in favor of scientific realism. This paper investigates the basis of this duality of epistemic assessments. It is claimed that the duality rests on two different notions of epistemic justification that are well-known from the debate on internalism and externalism in general epistemology: a deontological and an alethic notion. By discussing the conditions for the scientific acceptability of empirical results, it is argued that intrascientific justification employs the deontological notion. Philosophical disputes such as those on scientific realism can by contrast be shown to rest on the alethic notion. The implications of these findings both for the nature of the respective epistemic projects and for their interrelation are explored.