Progression along the bipolar spectrum: a longitudinal study of predictors of conversion from bipolar spectrum conditions to bipolar I and II disorders

Little longitudinal research has examined progression to more severe bipolar disorders in individuals with "soft" bipolar spectrum conditions. We examine rates and predictors of progression to bipolar I and II diagnoses in a nonpatient sample of college-age participants (n = 201) with high General Behavior Inventory scores and childhood or adolescent onset of "soft" bipolar spectrum disorders followed longitudinally for 4.5 years from the Longitudinal Investigation of Bipolar Spectrum (LIBS) project. Of 57 individuals with initial cyclothymia or bipolar disorder not otherwise specified (BiNOS) diagnoses, 42.1% progressed to a bipolar II diagnosis and 10.5% progressed to a bipolar I diagnosis. Of 144 individuals with initial bipolar II diagnoses, 17.4% progressed to a bipolar I diagnosis. Consistent with hypotheses derived from the clinical literature and the Behavioral Approach System (BAS) model of bipolar disorder, and controlling for relevant variables (length of follow-up, initial depressive and hypomanic symptoms, treatment-seeking, and family history), high BAS sensitivity (especially BAS Fun Seeking) predicted a greater likelihood of progression to bipolar II disorder, whereas early age of onset and high impulsivity predicted a greater likelihood of progression to bipolar I (high BAS sensitivity and Fun-Seeking also predicted progression to bipolar I when family history was not controlled). The interaction of high BAS and high Behavioral Inhibition System (BIS) sensitivities also predicted greater likelihood of progression to bipolar I. We discuss implications of the findings for the bipolar spectrum concept, the BAS model of bipolar disorder, and early intervention efforts.     

No postnatal maternal effect on male aggressiveness in wild-derived strains of house mice

Male aggressiveness is a complex behavior influenced by a number of genetic and non-genetic factors. Traditionally, the contribution of each of these factors has been established from experiments using artificially selected strains for high/low aggressive phenotypes. However, little is known about the factors underlying aggressive behavior in natural populations. In this study, we assess the influence of genetic background vs. postnatal maternal environment using a set of cross-fostering experiments between two wild-derived inbred strains, displaying high (STRA, derived from Mus musculus domesticus) and low (BUSNA, derived from Mus musculus musculus) levels of aggressiveness. The role of maternal environment was tested in males with the same genetic background (i.e. strain origin) reared under three different conditions: unfostered (weaned by mother), infostered (weaned by an unfamiliar dam from the same strain), and cross-fostered (weaned by a dam from a different strain). All males were tested against non-aggressive opponents from the A/J inbred strain. Resource-holding potential was assessed through body weight gains and territory ownership. The STRA males were shown to be aggressive in both neutral cage and resident-intruder tests. On the contrary, the BUSNA males were less aggressive in all tests. We did not find a significant effect of postnatal maternal environment; however, we detected significant maternal effect on body weight with differences between the strains, fostering type and interactions between these factors. We conclude that the aggressiveness preserved in the two strains has significant genetic component whose genetic basis can be dissected by quantitative trait loci analysis.     

Are we all in this together?: co-victimization,inclusive social identity and collective action in solidarity with the disadvantaged

Common experience of injustice can be a potent motivator of collective action and efforts to achieve social change - and of such efforts becoming more widespread. In this research, we propose that the effects of co-victimization on collective action are a function of inclusive social identity. Experiment 1 (N= 61) demonstrated that while presence (compared to absence) of co-victimization positively predicted consumer (i.e., participants) willingness to act collectively in solidarity with sweatshop workers, this effect was mediated by inclusive social identity. In Experiment 2 (N= 120), the salience of inclusive social identity was experimentally manipulated and interacted with co-victimization to predict collective action. When inclusive social identity was salient, co-victimization enhanced collective action, including willingness to pay extra for products made ethically and in support of fair wages for workers. In contrast, collective action was attenuated when co-victimization took place in the absence of inclusive social identity. Implications for understanding when co-victimization is transformed into common fate and political solidarity with the disadvantaged are discussed.     

Social Development of Preschool Children in Croatia: Contributions of Child Temperament, Maternal Life Satisfaction and Rearing Practices

We conducted the present study to examine the relationship of maternal characteristics (estimated happiness and life satisfaction, and child-rearing practices) and children’s temperament to conduct problems and prosocial behavior of preschool children in Croatia. Participants were mothers of 258 children (mean age 61.62 months), who gave their estimations on the Satisfaction with Life Scale, the Subjective Happiness Scale, the Parental Behaviour Questionnaire, the EAS Temperament Survey and the Strengths and Difficulties Questionnaire. After analyzing correlations between all the variables included in research, we conducted two hierarchical regression analyses with implementation of predictor variables in 4 stages (socio-demographic variables; mothers’ estimated happiness and life satisfaction; child temperament; mothers’ parenting). In the final step of regression significant predictors of preschoolers’ conduct problems were children’s age, temperamental emotionality and activity, and mothers’ punishment and inductive reasoning. When predicting children’s prosocial behavior, significant predictors were mothers’ inductive reasoning and warmth, and children’s age and temperamental shyness.     

Language-mediated object categorization: A longitudinal study with 16- to 20-month-old Serbian-speaking children

This study addressed the development of language-mediated categorization longitudinally, on a sample of Serbian-speaking children aged 16–20 months. Twenty four children were tested 3 consecutive times on: categorization of unknown objects with a shared label and a similar shape; and categorization of unknown objects with a shared label, but no visual similarity. The task was embedded in a game-like activity which included real object manipulation, categorization of novel objects labeled with made-up names, and socio-pragmatic cues provided by the experimenter. Our results indicate that an average child develops the ability to categorize novel objects with a similar shape and a shared label around 16 months of age, whereas for novel objects with a shared label, but no visual similarity, this ability is acquired sometime between 18 and 20 months of age. Our results partly confirm research findings obtained in other languages, thus emphasizing the need for cross-linguistic and cross-cultural validation of all language-related developmental studies.     

The role of retributive justice and the use of international criminal tribunals in post‐conflict reconciliation

Four experiments examined people's responses to intergroup violence either committed or suffered by their own group. Experiment 1 demonstrated that Serbs who strongly glorified Serbia were more supportive of future violence against, and less willing to reconcile with, Bosniaks after reading about Serbian victimization by Bosniaks rather than Serbian transgressions against Bosniaks. Replicating these effects with Americans in the context of American–Iranian tensions, Experiment 2 further showed that demands for retributive justice explained why high glorifiers showed asymmetrical reactions to ingroup victimization vs. perpetration. Again in the Serb and the American context, respectively, Experiments 3 and 4 demonstrated that post‐conflict international criminal tribunals can help satisfy victim group members' desire for retributive justice, and thereby reduce their support for future violence and increase their willingness to reconcile with the perpetrator group. The role of retributive justice and the use of international criminal justice in intergroup conflict (reduction) are discussed.