Effects of peripheral immune activation on social behavior and adrenocortical activity in aggressive mice: Genotype-environment interactions

To explore genetic-developmental differences in the biobehavioral effects of induced illness, males from two lines of mice selectively bred for high or low levels of aggressive behavior were injected with endotoxin (Escherichia coli, LPS: 0.25 mg/kg, 1.25 mg/kg, or 2.5 mg, i.p.) or saline. Body temperature, weight, and locomotor activity were monitored immediately before and 8 and 24 hr after injection. Twenty-four hours after injection, social behaviors were assessed in a 10-min dyadic test, and hypothalamus, spleen, and serum were collected. In both lines, endotoxin treatment increased behavioral immobility ("freezing") and decreased social exploration. Other effects showed line differences: Males from the high-aggressive line had a lower threshold to endotoxin-induced effects on body temperature, weight loss, spleen weight, and corticosterone. Social reactivity (startle response to mild social investigation) increased in the high-aggressive line and decreased in the low-aggressive line after treatment. In the high-aggressive line only, endotoxin decreased attack frequency and increased latency to attack. The interactions between selected line (genotype) and endotoxin treatment (environment) demonstrate that genetic-developmental differences in social and aggressive behavior may indicate the extent to which immune stimuli (e.g., bacteria, viruses, cytokines) function as "biobehavioral stressors." Aggr. Behav. 23:93–105, 1997.© 1997 Wiley-Liss, Inc.     

Custody evaluations: a survey of mental health professionals

Mental health professionals who conduct custody evaluations (N=165, 61% return rate) were surveyed about their practices and attitudes. These experts were primarily licensed psychologists, most with degrees in clinical and counseling. Few had specific training in child custody or forensic evaluation, and although they averaged 8·1 evaluations over the last year, most devoted a modest portion of their practice to custody work. They generally regarded custody evaluations as valuable to the courts, but were critical of the adversarial approach to determining custody. Procedures and priorities have changed little over the past decade, with most experts relying heavily on interviews and observation. Cautions are given regarding overstepping ethical guidelines and using procedures that presently lack established validity. © 1998 John Wiley & Sons, Ltd.     

The influence of musical distraction of varying complexity on the cognitive performance of extroverts and introverts

This study examined the effects of complexity in background music on the performance of four cognitive tasks by extroverts and introverts. In the presence of either ‘complex’ or ‘simple’ musical distraction or in silence, 24 introverts and 24 extroverts carried out a reading comprehension test, an observation test, and a memory test (in which recall was measured both immediately and after a six‐minute delay). An interaction was predicted such that increasing‐complexity musical distraction would result in the increase of extroverts', and the decrease of introverts', cognitive‐task performance. A significant interaction was obtained for three of the four tests: the observation test and both memory tests. These findings are discussed with regard to Eysenck's theory of personality. Copyright © 1999 John Wiley & Sons, Ltd.     

A defense of local miracle compatibilism

David Lewis has offered a reply to the standard argument for the claim that the truth of determinism is incompatible with anyone’s being able to do otherwise than she in fact does. Helen Beebee has argued that Lewis’s compatibilist strategy is untenable. In this paper I show that one recent attempt to defend Lewis’s view against this argument fails and then go on to offer my own defense of Lewis’s view.

Predicting having a best friend in young children: individual characteristics and friendship features

In this study, the authors investigated the characteristics that predict best friend status in young children. One hundred and twenty-four preschool, kindergarten, and first-grade children identified their "best friend" and up to four "other friends" in their class. Teachers completed a questionnaire about each friendship to determine positive and negative features of the relationships. First, the authors used individual characteristics to predict if a child had a best friend. The variables age, gender, and peer acceptance predicted that a child would have a best friend. Second, positive friendship features positively predicted best friendships in analyses of all friendship pairs. Best friendships are meaningful relationships to children even at this young age and offer children more positive experiences than do other friendships.     

Southern Culture and Homicide: Examining the Cracker Culture/Black Rednecks Thesis

Recent scholarship traces the roots of southern violence to the Scots-Irish, who brought a relatively violent “cracker culture” with them to the United States in the eighteenth century. The tolerance for violence inherent in cracker culture was believed to be transmitted throughout the south to other whites and was maintained, in part, through evangelical Christian doctrine. Moreover, Thomas Sowell (2005) recently argued that some southern blacks were also influenced by “cracker culture,” leading to the emergence of a “black redneck” phenomenon influencing homicide among blacks. Using county-level data circa 2000, this study empirically evaluates the merit of the cracker culture/black redneck thesis. Negative binomial regression analyses for a full sample of counties suggest that a measure of southern cracker/black redneck culture is an important factor affecting contemporary rates of argument homicide among both whites and blacks. When counties are divided into south and non-south sub-samples, the results are also consistent: a cracker/black redneck culture effect is evident for both racial groups in the south, and is also apparent outside of the southern region. We interpret these latter findings as possible support for the thesis that southern cracker/black redneck culture has been transported through migration to non-southern localities.     

The development of stranger fear in infancy and toddlerhood: normative development,individual differences,antecedents, and outcomes

Despite implications that stranger fear is an important aspect of developing behavioral inhibition, a known risk factor for anxiety, normative and atypical developmental trajectories of stranger fear across infancy and toddlerhood remain understudied. We used a large, longitudinal data set (N = 1285) including multi‐trait, multi‐method assessments of temperament to examine the normative course of development for stranger fear and to explore the possibility that individual differences exist in trajectories of stranger fear development between 6 and 36 months of age. A latent class growth analysis suggested four different trajectories of stranger fear during this period. Stable, high levels of stranger fear over time were associated with poorer RSA suppression at 6 months of age. Rates of concordance in trajectory‐based class membership for identical (monozygotic) and fraternal (dizygotic) twins, along with associations between atypical stranger fear development and greater anxiety‐related maternal characteristics, suggested that individual differences in developmental trajectories of stranger fear may be heritable. Importantly, trajectories of stranger fear during infancy and toddlerhood were linked to individual differences in behavioral inhibition, with chronically high levels of stranger fear and sharp increases in stranger fear over time related to greater levels of inhibition than other developmental trajectories.