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.     

“On the Move” or “Staying Put”: Locomotion,Need for Closure,and Reactions to Organizational Change1

Four studies conducted in various organizations in Italy, employing contemporaneous and longitudinal designs, tested hypotheses relating 2 personality constructs—need for cognitive closure ( Kruglanski & Webster, 1996 ) and locomotion tendency ( Higgins, Kruglanski, & Pierro, 2003 ; Kruglanski et al., 2000 )—to individuals’ ability to successfully cope with organizational change. Across diverse organizational settings, populations studied, types of organizational change implemented, and measures of coping with change, we found that need for closure was negatively related, and locomotion tendency was positively related, to coping with change. We also found that the negative relation between need for closure and coping was attenuated where organizational climate is supportive of change, and that degree of successful coping with change determines post‐change work attitudes.     

Effects of trophic poisoning with methylmercury on the appetitive elements of the agonistic sequence in fighting-fish (Betta splendens)

The aggressive display in Betta splendens is particularly prominent, and vital to its adaptation to the environment. Methylmercury is an organic variation of Hg that presents particularly pronounced neuro-behavioral effects. The present experiments aim to test the effect of acute and chronic poisoning with methylmercury on the display in Bettas. The animals were poisoned by trophic means in both experiments (16 ug/kg in acute poisoning; 16 ug/kg/day for chronic poisoning), and tested in agonistic pairs. The total frequency of the display was recorded, analyzing the topography of the agonistic response. The methylmercury seems to present a dose- and detoxification-dependent effect on these responses, with a more pronounced effect on motivity in acute poisoning and on emotionality in the chronic poisoning. It is possible that this effect could be mediated by alteration in the mono-amino-oxidase systems.     

Differentiation Processes for Social Stimuli with Different Degrees of Category Representativeness

The influence of the categorization process is investigated in the context of conceptions of categories as fuzzy sets, represented by prototypes. The experiment specifically considers two social categories corresponding to Italian regional groups: for each of these, stimuli were constructed which represented the respective categories in different degrees. We hypothesized that the accentuation of the degree in which individual exemplars represent a category, obtained by the addition of an attribute of the category, produces the effect of accentuating inter-category differences and intra-category similarities. Our results confirm the hypothesis regarding differentiation, but not that regarding assimilation. The effect of differentiation is strong at the category borders, i.e. for the less representative exemplars. A final issue considered is the theoretical problem of distinguishing, within the prototype of a category, between stereotypical attributes and those which permit categorial identification of individual cases.     

Bayesian inference for psychology. Part II: Example applications with JASP

Bayesian hypothesis testing presents an attractive alternative to p value hypothesis testing. Part I of this series outlined several advantages of Bayesian hypothesis testing, including the ability to quantify evidence and the ability to monitor and update this evidence as data come in, without the need to know the intention with which the data were collected. Despite these and other practical advantages, Bayesian hypothesis tests are still reported relatively rarely. An important impediment to the widespread adoption of Bayesian tests is arguably the lack of user-friendly software for the run-of-the-mill statistical problems that confront psychologists for the analysis of almost every experiment: the t-test, ANOVA, correlation, regression, and contingency tables. In Part II of this series we introduce JASP (http://www.jasp-stats.org), an open-source, cross-platform, user-friendly graphical software package that allows users to carry out Bayesian hypothesis tests for standard statistical problems. JASP is based in part on the Bayesian analyses implemented in Morey and Rouder’s BayesFactor package for R. Armed with JASP, the practical advantages of Bayesian hypothesis testing are only a mouse click away.     

Bayesian inference for psychology. Part I: Theoretical advantages and practical ramifications

Bayesian parameter estimation and Bayesian hypothesis testing present attractive alternatives to classical inference using confidence intervals and p values. In part I of this series we outline ten prominent advantages of the Bayesian approach. Many of these advantages translate to concrete opportunities for pragmatic researchers. For instance, Bayesian hypothesis testing allows researchers to quantify evidence and monitor its progression as data come in, without needing to know the intention with which the data were collected. We end by countering several objections to Bayesian hypothesis testing. Part II of this series discusses JASP, a free and open source software program that makes it easy to conduct Bayesian estimation and testing for a range of popular statistical scenarios (Wagenmakers et al. this issue).     

Latina Mothers’ Involvement in an HIV/STI and Substance Use Prevention Program for Adolescents: A Parallel Intervention Curriculum

As part of a larger HIV/STI/Substance Abuse Prevention intervention targeted to middle school students, we offered students’ parents an opportunity to participate in an adult education class. The same curricular materials were used for students enrolled in the intervention and for their parents. In the current study, mothers who had completed the adult education class participated in a focus group. The focus group explored what components of the intervention were perceived by mothers as particularly useful to them or to their child. Three core themes emerged from interpretive analyses of the focus group: (1) positive relationships with intervention staff and school personnel enticed students to participate in the intervention and facilitated parents’ involvement; (2) both students and parents felt respected and empowered by the intervention’s cornerstone values and curricular philosophy of cultural richness and pride in Hispanic/Latino heritage; and (3) mothers perceived their mastery of the course content—materially wholly dedicated to the health and wellness of their children—benefitted them in terms of both understanding the material and potentially allowing mothers to discuss health-oriented behavior with their young adolescent child.     

On the importance of avoiding shortcuts in applying cognitive models to hierarchical data

Psychological experiments often yield data that are hierarchically structured. A number of popular shortcut strategies in cognitive modeling do not properly accommodate this structure and can result in biased conclusions. To gauge the severity of these biases, we conducted a simulation study for a two-group experiment. We first considered a modeling strategy that ignores the hierarchical data structure. In line with theoretical results, our simulations showed that Bayesian and frequentist methods that rely on this strategy are biased towards the null hypothesis. Secondly, we considered a modeling strategy that takes a two-step approach by first obtaining participant-level estimates from a hierarchical cognitive model and subsequently using these estimates in a follow-up statistical test. Methods that rely on this strategy are biased towards the alternative hypothesis. Only hierarchical models of the multilevel data lead to correct conclusions. Our results are particularly relevant for the use of hierarchical Bayesian parameter estimates in cognitive modeling.