Learning strategy is influenced by trait anxiety and early rearing conditions in prepubertal male, but not prepubertal female rats

Rodents solve dual-solution tasks that require navigation to a goal by adopting either a hippocampus-dependent place strategy or a striatum-dependent stimulus-response strategy. A variety of factors, including biological sex and emotional status, influence the choice of learning strategy. In these experiments, we investigated the relationship between learning strategy and anxiety level in male and female rats prior to the onset of puberty, before the activational effects of gonadal hormones influence these processes. In the first experiment, prepubertal male rats categorized as high in trait anxiety at 26days of age exhibited a bias toward stimulus-response strategy at 28days of age, whereas age-matched females exhibited no preference in strategy regardless of anxiety level. In the second experiment, male and female rats were separated from their dams for either 15 or 180min per day during the first 2weeks of life and tested on a battery of anxiety and cognitive tasks between 25 and 29days of age. Prolonged maternal separations for 180min were associated with impaired spatial memory on a Y-maze task in both prepubertal males and females. Furthermore, prolonged maternal separations were linked to elevated anxiety and a bias for stimulus-response strategy in prepubertal males but not females. Alternatively, brief separations from dams for 15min were associated with intact spatial memory, lower levels of anxiety, and no preference for either learning strategy in both sexes. These results provide evidence of sex-specific effects of trait anxiety and early maternal separation on the choice of learning strategy used by prepubertal rodents.     

Attending to detail by communal spider-eating spiders

Communal predators may often need to make especially intricate foraging decisions, as a predator's success may depend on the actions of its neighbours. Here,we consider the decisions made by Portia africana, a jumping spider (Salticidae) that preys on other spiders, including Oecobius amboseli (Oecobiidae), a small prey spider that lives under small sheets of silk (nests) on the walls of buildings. P. africana juveniles settle near oecobiid nests and then ambush oecobiids as they leave or enter the nest. Two or more P. africana juveniles sometimes settle at the same nest and, when an oecobiid is captured, the P. africana juveniles may share the meal. We investigated the joining decisions made by na?ve P. africana juveniles. Experiments were based on using lures (dead spiders positioned in lifelike posture) arranged in a series of 17 different scenes defined by the presence/absence of a nest, the lure types present and the configuration of the lures and the nest. Our findings imply that P. africana juveniles make remarkably precise predatory decisions, with the variables that matter including whether a nest is present, the identity of spiders inside and outside a nest and how spiders are positioned relative to each other and the nest.     

Bridging a yawning chasm: EEG investigations into the debate concerning the role of the human mirror neuron system in contagious yawning

Ongoing debate in the literature concerns whether there is a link between contagious yawning and the human mirror neuron system (hMNS). One way of examining this issue is with the use of the electroencephalogram (EEG) to measure changes in mu activation during the observation of yawns. Mu oscillations are seen in the alpha bandwidth of the EEG (8–12 Hz) over sensorimotor areas. Previous work has shown that mu suppression is a useful index of hMNS activation and is sensitive to individual differences in empathy. In two experiments, we presented participants with videos of either people yawning or control stimuli. We found greater mu suppression for yawns than for controls over right motor and premotor areas, particularly for those scoring higher on traits of empathy. In a third experiment, auditory recordings of yawns were compared against electronically scrambled versions of the same yawns. We observed greater mu suppression for yawns than for the controls over right lateral premotor areas. Again, these findings were driven by those scoring highly on empathy. The results from these experiments support the notion that the hMNS is involved in contagious yawning, emphasise the link between contagious yawning and empathy, and stress the importance of good control stimuli.     

An overview of South African psychology

This overview of psychology in South Africa presents a concise and historical account of its science and practice, from its early origins in the late nineteenth century to the present, and traces seminal influences on the discipline. It is a review of how psychology in South Africa developed over more than a century to become one of the most popular subjects in universities and an established and recognized profession, whose members play a variety of roles in the South African polity and larger society. The impact that apartheid racism had on key aspects of psychology's development is traversed, and the influences that previous ruling party politics had on professional psychological organizations are delineated. The unification of psychology under the Psychological Society of South Africa, a few months before the advent of democracy in South Africa, is explicated. The protection of the title of psychologist in law and certain other changes in the legislative environment, enabling a greater role for psychologists, are reported. The primary research sites for psychology and its funding and the main university psychology programs are described, as are the requirements for registration and licensure. The genesis and the importance of the work of internationally acclaimed South African psychologists, such as J. Wolpe and A. A. Lazarus, are contextualized. With the increased participation of progressive black psychologists in leadership and research in the past two decades, a transformed psychology has the potential to play a significant role in addressing human issues confronting South Africa.     

A quasi-experimental analysis of the influence of neighborhood disadvantage on child and adolescent conduct problems

A quasi-experimental comparison of cousins differentially exposed to levels of neighborhood disadvantage (ND) was used with extensive measured covariates to test the hypothesis that neighborhood risk has independent effects on youth conduct problems (CPs). Multilevel analyses were based on mother-rated ND and both mother-reported CPs across 4-13 years (n = 7,077) and youth-reported CPs across 10-13 years (n = 4,524) from the Children of the National Longitudinal Survey of Youth. ND was robustly related to CPs reported by both informants when controlling for both measured risk factors that are correlated with ND and unmeasured confounds. These findings are consistent with the hypothesis that ND has influence on conduct problems.     

Deconstructing the age-prevalence curve of alcohol dependence: why "maturing out" is only a small piece of the puzzle

Epidemiological studies have consistently demonstrated that heavy alcohol use and alcohol dependence (AD) tend to increase in adolescence and emerging adulthood and then show a large decline in the late 20s, a phenomenon called maturing out. This decline has been explained as an effect of "role incompatibility" in which involvement in new roles and activities interferes with a heavy drinking lifestyle. However, maturing out has been conceived mostly as a decrease in offset, with little attention paid to reductions in new onset or recurrence across decades of life. Moreover, although role incompatibility processes have been studied with young samples, little is known about the effect of life transitions (e.g., marriage, parenthood, changes in employment status) on AD later in life and whether similar effects are observed. Using longitudinal data from the National Epidemiologic Survey on Alcohol and Related Conditions, a nationally representative epidemiologic survey, we examined the patterns of stability and change in AD across the life span and the differential effect of life transitions on AD across different age strata. Results showed that persistence of AD tended to increase with age, although not dramatically, and that onset and recurrence tended to decrease with age. Moreover, the effects of life transitions on the course of AD varied across the life span and were different for men and women. These results indicate that life transitions differentially affect the patterns of stability and change in younger versus older people, have a different impact for men and women, and highlight the need to consider the unique aspects of each stage of adult development on the course of AD.     

An invariant dimensional liability model of gender differences in mental disorder prevalence: evidence from a national sample

Epidemiological studies of categorical mental disorders consistently report that gender differences exist in many disorder prevalence rates and that disorders are often comorbid. Can a dimensional multivariate liability model be developed to clarify how gender impacts diverse, comorbid mental disorders? We pursued this possibility in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; N = 43,093). Gender differences in prevalence were systematic such that women showed higher rates of mood and anxiety disorders, and men showed higher rates of antisocial personality and substance use disorders. We next investigated patterns of disorder comorbidity and found that a dimensional internalizing-externalizing liability model fit the data well, where internalizing is characterized by mood and anxiety disorders, and externalizing is characterized by antisocial personality and substance use disorders. This model was gender invariant, indicating that observed gender differences in prevalence rates originate from women and men's different average standings on latent internalizing and externalizing liability dimensions. As hypothesized, women showed a higher mean level of internalizing, while men showed a higher mean level of externalizing. We discuss implications of these findings for understanding gender differences in psychopathology and for classification and intervention.     

Social connection enables dehumanization

Being socially connected has considerable benefits for oneself, but may have negative consequences for evaluations of others. In particular, being socially connected to close others satisfies the need for social connection, and creates disconnection from more distant others. We therefore predicted that feeling socially connected would increase the tendency to dehumanize more socially distant others. Four experiments support this prediction. Those led to feel socially connected were less likely to attribute humanlike mental states to members of various social groups (Experiments 1 and 2), particularly distant others compared to close others (Experiment 3), and were also more likely to recommend harsh treatment for dehumanized others (i.e., terrorist detainees, Experiment 4). Discussion addresses the mechanisms by which social connection enables dehumanization, and the varied behavioral implications that result.