Environmental enrichment protects against the effects of chronic stress on cognitive and morphological measures of hippocampal integrity

Chronic stress has detrimental effects on hippocampal integrity, while environmental enrichment (EE) has beneficial effects when initiated early in development. In this study, we investigated whether EE initiated in adulthood would mitigate chronic stress effects on cognitive function and hippocampal neuronal architecture, when EE started one week before chronic stress began, or two weeks after chronic stress onset. Adult male Sprague Dawley rats were chronically restrained (6h/d) or assigned as non-stressed controls and subdivided into EE or non-EE housing. After restraint ended, rats were tested on a radial arm water maze (RAWM) for 2-d to assess spatial learning and memory. The first study showed that when EE began prior to 3-weeks of chronic stress, EE attenuated chronic stress-induced impairments in acquisition, which corresponded with the prevention of chronic stress-induced reductions in CA3 apical dendritic length. A second study showed that when EE began 2-weeks after the onset of a 5-week stress regimen, EE blocked chronic stress-induced impairments in acquisition and retention at 1-h and 24-h delays. RAWM performance corresponded with CA3 apical dendritic complexity. Moreover, rats in EE housing (control or stress) exhibited similar corticosterone profiles across weeks, which differed from the muted corticosterone response to restraint by the chronically stressed pair-housed rats. These data support the interpretation that chronic stress and EE may act on similar mechanisms within the hippocampus, and that manipulation of these factors may yield new directions for optimizing brain integrity and resilience under chronic stress or stress related neuropsychological disorders in the adult.     

Evidence for the criterion validity and clinical utility of the Pathological Narcissism Inventory

In this study, the authors evaluated aspects of criterion validity and clinical utility of the grandiosity and vulnerability components of the Pathological Narcissism Inventory (PNI) using two undergraduate samples (N = 299 and 500). Criterion validity was assessed by evaluating the correlations of narcissistic grandiosity and narcissistic vulnerability with established indices of normal personality traits, psychopathology and clinical concerns, and pathological personality traits. Overall, the pattern of correlations supported the convergent and discriminant validity of grandiose and vulnerable conceptualizations of pathological narcissism as measured by the PNI. Clinical utility was assessed by evaluating the extent to which clinicians without specific training in pathological narcissism as well as clinicians with expertise in pathological narcissism could accurately predict the correlates of PNI grandiosity and vulnerability with normal and pathological personality traits and psychopathology. The r(contrast-cv) coefficient provided a global index of accuracy in clinicians' predictions that was more fully elaborated by examining systematic discrepancies across groups. Overall, novice and expert clinicians were generally able to predict criterion correlations, with some exceptions (e.g., counter to predictions, pathological narcissism was negatively associated with treatment resistance). These results provide further evidence regarding the validity and utility of the narcissistic grandiosity and narcissistic vulnerability constructs as measured by the PNI.     

Knowledge of sex-role stereotypes in children aged 3 to 5

When do children begin acquiring adult sex-role stereotypes? This study examined the sex-stereotypic knowledge of four groups of young children: 3.0–3.5, 3.5–4.0, 4.0–4.5, and 4.5–5.0 years old. To assess the development of their knowledge, the same children were retested six months later. Evidence of sex-stereotyping appeared at 3.5 years and increased both across the different age groups and within the same children as they aged. The children's knowledge encompassed both feminine and masculine traits, and was related to general intellectual development. These results are interpreted as supporting cognitive-developmental theories that children learn sex-role stereotypes as structural rules for organizing and understanding behaviors present in their social environment.Thanks are due to Diane Bulow, Grace Horsman, Barbara Kutner, Joan Strutts, and the other teachers for aiding our access to children enrolled in their centers. Moira Davidson, Beth Kaplan, Keith Miller, Suzanna Nam, Dan Birecree, Sara Corse, Jim Gilbert, Jean Merenda, Anna Steiner, and Steve Tannenbaum served graciously as testers.     

WARRANT FOR NOTHING (AND FOUNDATIONS FOR FREE)?

My life consists in my being content to accept many things
(Wittgenstein On Certainty x344)
Two kinds of epistemological sceptical paradox are reviewed and a shared assumption, that warrant to accept a proposition has to be the same thing as having evidence for its truth, is noted. 'Entitlement', as used here, denotes a kind of rational warrant that counter-exempli.es that identi.cation. The paper pursues the thought that there are various kinds of entitlement and explores the possibility that the sceptical paradoxes might receive a uniform solution if entitlement can be made to reach sufficiently far. Three kinds of entitlement are characterised and given prima facie support, and a fourth is canvassed. Certain foreseeable limitations of the suggested anti-sceptical strategy are noted. The discussion is grounded, overall, in a conception of the sceptical paradoxes not as directly challenging our having any warrant for large classes of our beliefs but as crises of intellectual conscience for one who wants to claim that we do.