Learning to learn causal models

Learning to understand a single causal system can be an achievement, but humans must learn about multiple causal systems over the course of a lifetime. We present a hierarchical Bayesian framework that helps to explain how learning about several causal systems can accelerate learning about systems that are subsequently encountered. Given experience with a set of objects, our framework learns a causal model for each object and a causal schema that captures commonalities among these causal models. The schema organizes the objects into categories and specifies the causal powers and characteristic features of these categories and the characteristic causal interactions between categories. A schema of this kind allows causal models for subsequent objects to be rapidly learned, and we explore this accelerated learning in four experiments. Our results confirm that humans learn rapidly about the causal powers of novel objects, and we show that our framework accounts better for our data than alternative models of causal learning.     

Medroxyprogesterone acetate impairs memory and alters the GABAergic system in aged surgically menopausal rats

In women, medroxyprogesterone acetate (MPA) is the most commonly used progestin component of hormone therapy (HT). In vitro, MPA negatively impacts markers of neuronal health and exacerbates experimentally-induced neurotoxicity. There is in vitro evidence that these factors are driven by GABAergic and neurotrophic systems. Whether these effects translate to a negative impact on brain function has not been tested in vivo, clinically or preclinically. Here we evaluate the mnemonic and neurobiological effects of MPA in the surgically menopausal rat. Aged ovariectomized (OVX) rats were given subcutaneous vehicle, natural progesterone, low-dose MPA or high-dose MPA. Multiple cognitive domains were analyzed via the water radial-arm maze (WRAM) and Morris maze (MM). Cognitive brain regions were assayed for changes in the GABAergic system by evaluating GAD protein, the synthesizing enzyme for GABA, and neurotrophins. On the WRAM, both progestin types impaired learning. Further, high-dose MPA impaired delayed memory retention on the WRAM, and exacerbated overnight forgetting on the MM. While neurotrophins were not affected by progesterone or MPA treatment, both progestin types altered GAD levels. MPA significantly and progesterone marginally decreased GAD levels in the hippocampus, and both MPA and progesterone significantly increased GAD levels in the entorhinal cortex. These findings suggest that MPA, the most commonly used progestin in HT, is detrimental to learning and two types of memory, and modulates the GABAergic system in cognitive brain regions, in aged surgically menopausal rats. These findings, combined with in vitro evidence that MPA is detrimental to neuronal health, indicates that MPA has negative effects for brain health and function.     

Egos inflating over time: a cross-temporal meta-analysis of the Narcissistic Personality Inventory

ABSTRACT A cross-temporal meta-analysis found that narcissism levels have risen over the generations in 85 samples of American college students who completed the 40-item forced-choice Narcissistic Personality Inventory (NPI) between 1979 and 2006 (total n =16,475). Mean narcissism scores were significantly correlated with year of data collection when weighted by sample size (β=.53, p <.001). Since 1982, NPI scores have increased 0.33 standard deviation. Thus, almost two-thirds of recent college students are above the mean 1979–1985 narcissism score, a 30% increase. The results complement previous studies finding increases in other individualistic traits such as assertiveness, agency, self-esteem, and extraversion.     

A comparison of the Psychological Entitlement Scale and the Narcissistic Personality Inventory's Entitlement Scale: relations with general personality traits and personality disorders

Given the negative consequences of psychological entitlement, it is important to have a reliable and valid measure of the construct. We used an undergraduate sample (N = 271) to examine the Entitlement subscale (ENT) of the Narcissistic Personality Inventory (Raskin & Terry, 1988) and the Psychological Entitlement Scale (PES; Campbell, Bonacci, Shelton, Exline, & Bushman, 2004) in relation to general personality traits (i.e., Revised NEO Personality Inventory; Costa & McCrae, 1992) and personality disorders (PDs; Personality Diagnostic Questionnaire-4; Hyler, 1994). We found similar personality correlates (e.g., disagreeableness; Cluster B PDs) for both measures, although ENT was comprised of greater disagreeableness and less warmth and positive affect. ENT was also more positively associated with schizoid and borderline PDs compared to the PES. Overall, these measures are closely related with regard to their relations with general and pathological personality dimensions, although the ENT scale may capture a slightly more pathological variant.     

Acoustic interaction in animal groups: signaling in noisy and social contexts

It has long been known that individuals of many species vocally communicate with one another in noisy environments and in rich contexts of social interaction. It has recently become clear that researchers interested in understanding acoustic communication in animal groups must study vocal signaling in these noisy and socially complex settings. Furthermore, recent methodological advances have made it increasingly clear that the authors can tackle these more complex questions effectively. The articles in this Special Issue stem from a Symposium held at the June 2006 meeting of the Acoustical Society of America, and illustrate some of the taxonomic and methodological diversity in studies aimed at understanding how acoustic communication functions in social grouping. This introduction to the Special Issue provides a brief overview of the articles and key ideas in this field of inquiry, and suggests some future directions to take the field to help us understand how social pressures in animal groups may influence, and be influenced by, acoustic signals.     

Malingering as a categorical or dimensional construct: the latent structure of feigned psychopathology as measured by the SIRS and MMPI-2

The 6 nonoverlapping primary scales of the Structured Interview of Reported Symptoms (SIRS) were subjected to taxometric analysis in a group of 1,211 criminal and civil examinees in order to investigate the latent structure of feigned psychopathology. Both taxometric procedures used in this study, mean above minus below a cut (MAMBAC) and maximum covariance (MAXCOV), produced dimensional results. A subgroup of participants (n = 711) with valid Minnesota Multiphasic Personality Inventory-2 (MMPI-2) protocols were included in a second round of analyses in which the 6 nonoverlapping primary scales of the SIRS and the Infrequency (F), Infrequency-Psychopathology (Fp), and Dissimulation (Ds) scales of the MMPI-2 served as indicators. Again, the results were more consistent with dimensional latent structure than with taxonic latent structure. On the basis of these findings, it is concluded that feigned psychopathology forms a dimension (levels of fabrication or exaggeration) rather than a taxon (malingering-honest dichotomy) and that malingering is a quantitative distinction rather than a qualitative one. The theoretical and clinical practice implications of these findings are discussed.     

Acute ethanol ingestion impairs appetitive olfactory learning and odor discrimination in the honey bee

Invertebrates are valuable models for increasing our understanding of the effects of ethanol on the nervous system, but most studies on invertebrates and ethanol have focused on the effects of ethanol on locomotor behavior. In this work we investigate the influence of an acute dose of ethanol on appetitive olfactory learning in the honey bee (Apis mellifera), a model system for learning and memory. Adult worker honey bees were fed a range of doses (2.5%, 5%, 10%, or 25%) of ethanol and then conditioned to associate an odor with a sucrose reward using either a simple or differential conditioning paradigm. Consumption of ethanol before conditioning significantly reduced both the rate of acquisition and the asymptotic strength of the association. Honey bees also exhibited a dose dependent reduction in arousal/attention during conditioning. Consumption of ethanol after conditioning did not affect recall 24h later. The observed deficits in acquisition were not due to the affect of ethanol on gustatory sensitivity or motor function. However, honey bees given higher doses of ethanol had difficulty discriminating amongst different odors suggesting that ethanol consumption influences olfactory processing. Taken together, these results demonstrate that an acute dose of ethanol affects appetitive learning and olfactory perception in the honey bee.     

The costs of benefits: help-refusals highlight key trade-offs of social life.

Social living provides opportunities for cooperative interdependence and concomitant opportunities to obtain help from others in times of need. Nevertheless, people frequently refuse help from others, even when it would be beneficial. Decisions to accept or reject aid offers may provide a window into the adaptive trade-offs recipients make between costs and benefits in different key domains of social life. Following from evolutionary and ecological perspectives, we consider how help-recipient decision making might reflect qualitatively different threats to goal attainment within six fundamental domains of social life (coalition formation, status, self-protection, mate acquisition, mate retention, and familial care). Accepting help from another person is likely to involve very different threats and opportunities depending on which domains are currently active. This approach can generate a variety of novel empirical predictions and suggest new implications for the delivery of aid.     

Trouble crossing the bridge: altered interhemispheric communication of emotional images in anxiety

Worry is thought to involve a strategy of cognitive avoidance, in which internal verbalization acts to suppress threatening emotional imagery. This study tested the hypothesis that worry-prone individuals would exhibit patterns of between-hemisphere communication that reflect cognitive avoidance. Specifically, the hypothesis predicted slower transfer of threatening images from the left to the right hemisphere among worriers. Event-related potential (ERP) measures of interhemispheric transfer time supported this prediction. Left-to-right hemisphere transfer times for angry faces were relatively slower for individuals scoring high in self-reported worry compared with those scoring low, whereas transfer of happy and neutral faces did not differ between groups. These results suggest that altered interhemispheric communication may constitute one mechanism of cognitive avoidance in worry.     

STEREOTYPE THREAT AND THE GENDER GAP IN POLITICAL KNOWLEDGE

Men tend to achieve higher response accuracy than women on surveys of political knowledge. We investigated the possibility that this performance gap is moderated by factors that render the communicative context of a survey intellectually threatening to women and thereby induce stereotype threat. In a telephone survey of college students' political knowledge, we manipulated two factors of the survey context: the alleged diagnosticity of the question set (i.e., whether it was portrayed as being sensitive to potential gender differences) and the gender of the interviewer. Consistent with previous studies of political knowledge, men scored higher than women overall. However, as predicted, this difference was reliably moderated by the manipulated factors. Women's scores were not reliably different from men's when the survey was portrayed as nondiagnostic and when women were interviewed by female interviewers. Diagnosticity and interviewer gender had no effects on men's scores. Consistent with previous research on stereotype threat, these results suggest that explicit and implicit cues reminding women of the possibility that they might confirm a negative gender stereotype can impair their retrieval of political knowledge.