Genetic and environmental bases of childhood antisocial behavior: a multi-informant twin study

Genetic and environmental influences on childhood antisocial and aggressive behavior (ASB) during childhood were examined in 9- to 10-year-old twins, using a multi-informant approach. The sample (605 families of twins or triplets) was socioeconomically and ethnically diverse, representative of the culturally diverse urban population in Southern California. Measures of ASB included symptom counts for conduct disorder, ratings of aggression, delinquency, and psychopathic traits obtained through child self-reports, teacher, and caregiver ratings. Multivariate analysis revealed a common ASB factor across informants that was strongly heritable (heritability was .96), highlighting the importance of a broad, general measure obtained from multiple sources as a plausible construct for future investigations of specific genetic mechanisms in ASB. The best fitting multivariate model required informant-specific genetic, environmental, and rater effects for variation in observed ASB measures. The results suggest that parents, children, and teachers have only a partly "shared view" and that the additional factors that influence the "rater-specific" view of the child's antisocial behavior vary for different informants. This is the first study to demonstrate strong heritable effects on ASB in ethnically and economically diverse samples.     

The validity of using prior ratings of perceive exertion to regulate resistance exercise intensity

This investigation examined the validity of using ratings of perceived exertion (RPE) to regulate intensity during resistance exercise. 19 male (M age = 22.2 yr., SD = 2.7) and 19 female (M age = 21.4 yr., SD = 2.3) participants estimated exertion when performing the knee extension at 40% to 90% of one-repetition maximum. One week later, participants were asked to produce weights for the knee extension that elicited the feelings of exertion associated with 9, 13, and 17 on the Borg RPE scale. The weight produced at 9, 13, and 17 during the production session was compared to the weight lifted at each RPE during the estimation session. The effect sizes associated with the differences in weight lifted across sessions at each RPE were generally small in magnitude, especially at the higher intensities (ES = .40, -.09, .15, respectively). The results of this investigation support the use of RPE as a method of prescribing the intensity of resistance exercise.     

Brief experimental analysis of early reading interventions

The purpose of this study was to investigate how brief experimental analyses (BEAs) could be used to identify effective interventions for Kindergartners (2 girls and 2 boys, 5 years and 7-10 months old) with low performance and/or growth slope in letter sound fluency (LSF). Interventions were tested within a multielement design with brief mini-reversals until an intervention yielding at least 20% improvement on a specific subskill measure or a curriculum-based measure of LSF was identified. BEA-identified interventions were implemented one-on-one for 5 to 9 weeks. A multiple-baseline design across participants showed large intervention effects (average adjusted d = 2.4) on general outcome measures, supporting treatment validity of BEAs. Findings extend the BEA literature to younger participants, early reading interventions, and early reading measures.     

Resolving Nationalist Conflicts: Promoting Overlapping Identities and Pooling Sovereignty—The 1998 Northern Irish Peace Agreement

Nationalist and ethnic conflicts are a continuing source of tension in the post–Cold War period. The underlying factors affecting such conflicts are threat perception, ethnic security dilemmas, and lack of trust between nationalist/ethnic groups. The challenge is to find solutions to these conflicts. International institutions can establish trust and reduce the ethnic security dilemma by providing multiple forums of representation, promoting overlapping identities, and pooling sovereignty. Pooling sovereignty across a number of international representative bodies leads to increased access to governmental policymaking, with each party having a stake in government, and leads to a reduction in political tension and conflict. Thus, international parliamentary institutions may provide a solution to these conflicts. The British-Irish Peace Agreement (Good Friday Agreement) of 1998 is examined as an illustration of this argument.     

NO QUICK FIXES: ADDING CONTENT ABOUT WOMEN TO ECOLOGY COURSE MATERIALS

This study reports on a three-semester model project designed to assess the impact of enriched content related to Women's and Gender Studies on students enrolled in an undergraduate ecology course. The two constructs of interest were (a) students' attitudes toward women in science and society and (b) students' assessment of the classroom climate for women. The data included 398 matched pretest and posttest survey responses from a control group, a minimal enrichment group, and an increased enrichment group. Findings indicated that, although small course revisions did not influence students' attitudes toward women in science and society, such revisions had a positive influence on students' assessments of the classroom climate.     

PERCEPTIONS OF RELATIONAL AND PHYSICAL AGGRESSION AMONG COLLEGE STUDENTS: EFFECTS OF GENDER OF PERPETRATOR, TARGET, AND PERCEIVER

This study examined gendered perceptions of relational and physical aggressive behaviors and personal experiences with both types of aggression. Prior research suggested that physical aggression by males and relational aggression by females would be perceived most negatively. College students (186 female, 128 male) rated the acceptability and harmfulness of aggression in scenarios in which type of aggression and perpetrator and target gender were varied. As predicted, relational aggression by female characters and physical aggression by male characters were rated as less acceptable and more aggressive/harmful than the same behavior by the other gender. Thus, expectations regarding the gender-appropriateness of aggression appear to affect perceptions of such acts. Despite popular conceptions that females use and are harmed by relational aggression more than males, there was no gender difference in experience with relational aggression, nor were female targets viewed as more harmed by such aggression than their male counterparts.     

Cognitive triad: Relationship to depressive symptoms,parents' cognitive triad,and perceived parental messages

Evaluating the relationship between children's depressogenic thinking, children's depressive symptoms, parents' depressogenic thinking, and perceived parental messages about the self, world, and future was the primary objective of this investigation. Children (n =133) from grades 4 to 7 completed measures of depression and anxiety, including a semistructured clinical interview, a measure of their cognitive triad, and a measure of perceived parental messages about the self, world, and future. Mothers (n =112) and fathers (n =95) completed a measure of their own cognitive triad. Results of a series of regression analyses revealed that (1) children's views of self, world, and future (cognitive triad) are related to severity of depression; (2) mothers' but not fathers' cognitive triads are related to their children's cognitive triads; (3) perceived parental messages to the children about the self, world, and future are predictive of the children's cognitive triads and ratings of depression; and (4) the relationship between perceived parental messages and depression is completely mediated by children's cognitive triads. Analyses of covariance indicated that the obtained mediational relationship between children's views of self, world, and future, perceived parental messages, and children's depressive symptoms was specific to depressive versus anxious symptomatology. Impfications for existing theory and research are discussed.     

Caffeine,impulsivity, and memory scanning: A comparison of two explanations for the Yerkes-Dodson Effect

Two explanations for the Yerkes-Dodson Effect (1908) were tested. Easterbrook (1959) proposed that arousal reduces the range of cue utilization. Thus, arousal should interfere with the capacity for simultaneous (dual) memory scans. In contrast, Humphreys and Revelle (1984) proposed that arousal facilitates sustained information transfer but interferes with short-term memory. Arousal should thus reduce the time needed to prepare to respond but increase the time needed to scan memory. Either caffeine or placebo was given to 78 subjects who differed in impulsivity. They completed three versions of a memory-scanning task: two single-task versions (physical and category matches) and one dual-task version (either type of match). As predicted by Humphreys and Revelle, relative to placebo, caffeine lowered the intercept (p<.01), suggesting facilitation of sustained information transfer, but increased the slope (p<.05), suggesting impairment of access to short-term memory, of the regression of reaction time on log-transformed memory-set size. That caffeine had a main effect on slopes and on intercepts but did not interact with type of task suggests that arousal does not necessarily disrupt dual-task performance.     

Reinforcement uncertainty enhances preference for choice in humans

Under concurrent‐chains schedules of reinforcement, participants often prefer situations that allow selection among alternatives (free choice) to situations that do not (forced choice). The present experiment examined the effects of reinforcement probability on choice preferences. Preferences for free versus forced choice were measured under a condition in which participants' choices were always reinforced (reinforcement probability of 1.0) and a condition in which outcomes were uncertain (reinforcement probability of 0.5). Forty‐four college students participated and preferences were examined under a concurrent‐chains schedule of reinforcement. Participants preferred free choice under uncertain reinforcement, but a bias toward free choice was not observed when reinforcement was certain. These results align with previous findings of preference for free choice under conditions of uncertainty, but suggest that preference may be dependent upon probabilistic reinforcement contingencies in the terminal links of the concurrent‐chains arrangement. Thus, reinforcement probability is an important variable to consider when conducting similar studies on the value of choice.