Sex differences in the genetic and environmental influences on childhood conduct disorder and adult antisocial behavior

Sex differences in the genetic and environmental influences on childhood conduct disorder and adult antisocial behavior were examined in a large community sample of 6,383 adult male, female, and opposite-sex twins. Retrospective reports of childhood conduct disorder (prior to 18 years of age) were obtained when participants were approximately 30 years old, and lifetime reports of adult antisocial behavior (antisocial behavior after 17 years of age) were obtained 8 years later. Results revealed that either the genetic or the shared environmental factors influencing childhood conduct disorder differed for males and females (i.e., a qualitative sex difference), but by adulthood, these sex-specific influences on antisocial behavior were no longer apparent. Further, genetic and environmental influences accounted for proportionally the same amount of variance in antisocial behavior for males and females in childhood and adulthood (i.e., there were no quantitative sex differences). Additionally, the stability of antisocial behavior from childhood to adulthood was slightly greater for males than females. Though familial factors accounted for more of the stability of antisocial behavior for males than females, genetic factors accounted for the majority of the covariation between childhood conduct disorder and adult antisocial behavior for both sexes. The genetic influences on adult antisocial behavior overlapped completely with the genetic influences on childhood conduct disorder for both males and females. Implications for future twin and molecular genetic studies are discussed.     

Disordered gambling as defined by the Diagnostic and Statistical Manual of Mental Disorders and the South Oaks Gambling Screen: evidence for a common etiologic structure

In a previous article, we demonstrated in a large twin study that disordered gambling (DG), as defined by the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV), ran in families, that about half of the variation in liability for DG was due to familial factors, and that all of this was explained by shared genetic rather than shared environmental influences (Slutske, Zhu, Meier, & Martin, 2010). The purpose of the present study is to extend this work to include an alternative conceptualization of DG that is provided by the South Oaks Gambling Screen (SOGS) item set in order to (a) compare the magnitude of the familial resemblance obtained when using the two definitions of DG (based on the DSM-IV and the SOGS), (b) examine the extent to which the 2 definitions tap the same underlying sources of genetic and environmental variation, and (c) examine whether the same results will be obtained among men and women. The results of bivariate twin model-fitting analyses suggested that DG, as defined by the DSM-IV and the SOGS, substantially overlapped at the etiologic level among both men and women, which supports the construct validity of both the DSM and the SOGS conceptualizations of DG. This study highlights the utility of twin studies for appraising the validity of the diagnostic nomenclature.     

Age differences in instability, contingency, and level of self-esteem across the life span

We investigated age differences in instability, contingency, and level of self-esteem from age 13 to 72 years, using data from 1386 individuals who participated in a diary study over 25 days. Instability and contingency of self-esteem decreased from adolescence to old age, whereas level of self-esteem increased. Big Five personality traits predicted the level, but not the slope, of the trajectories of self-esteem characteristics. Age differences in self-esteem characteristics did not merely reflect age differences in instability and level of positive and negative affect. Finally, self-esteem characteristics showed a stable pattern of interrelations across the life span. Overall, the findings suggest that people’s self-esteem tends to become better adjusted—i.e., more stable, less contingent, and higher—across the life course.     

Training synaesthesia

Synaesthetic inducers such as graphemes are typically cultural artifacts. Thus, a learning component seems evident in synaesthesia (Simner et al, 2009 Brain 132 57-64). Normally, synaesthetes report to have their experiences since they can remember. Nevertheless, a recent training study suggests that synaesthesia can be mimicked in non-synaesthetes. To date, the role of learning during the development of synaesthesia is still debated. It is not clear whether synaesthesia can be learned or trained at all. To address this question, we compared a non-adaptive and an adaptive training for their effectiveness. We assessed their impact on two types of priming tasks, before and after the training. We found stronger priming in the adaptive training group suggesting that adaptive training is more efficient to mimic synaesthesia.     

Predictors of race time in male ironman triathletes: physical characteristics, training, or prerace experience?

The aim of the present study was to assess whether physical characteristics, training, or prerace experience were related to performance in recreational male Ironman triathletes using bi- and multivariate analysis. 83 male recreational triathletes who volunteered to participate in the study (M age 41.5 yr., SD = 8.9) had a mean body height of 1.80 m (SD = 0.06), mean body mass of 77.3 kg (SD = 8.9), and mean Body Mass Index of 23.7 kg/m2 (SD = 2.1) at the 2009 IRONMAN SWITZERLAND competition. Speed in running during training, personal best marathon time, and personal best time in an Olympic distance triathlon were related to the Ironman race time. These three variables explained 64% of the variance in Ironman race time. Personal best marathon time was significantly and positively related to the run split time in the Ironman race. Faster running while training and both a fast personal best time in a marathon and in an Olympic distance triathlon were associated with a fast Ironman race time.     

Sex differences in association of race performance, skin-fold thicknesses, and training variables for recreational half-marathon runners

The purpose of this study was to investigate the association between selected skin-fold thicknesses and training variables with a half-marathon race time, for both male and female recreational runners, using bi- and multivariate analysis. In 52 men, two skin-fold thicknesses (abdominal and calf) were significantly and positively correlated with race time; whereas in 15 women, five (pectoral, mid-axilla, subscapular, abdominal, and suprailiac) showed positive and significant relations with total race time. In men, the mean weekly running distance, minimum distance run per week, maximum distance run per week, mean weekly hours of running, number of running training sessions per week, and mean speed of the training sessions were significantly and negatively related to total race time, but not in women. Interaction analyses suggested that race time was more strongly associated with anthropometry in women than men. Race time for the women was independently associated with the sum of eight skin-folds; but for the men, only the mean speed during training sessions was independently associated. Skin-fold thicknesses and training variables in these groups were differently related to race time according to their sex.     

What matters in implicit task sequence learning: perceptual stimulus features, task sets, or correlated streams of information?

Implicit task sequence learning may be attributed to learning the order of perceptual stimulus features associated with the task sequence, learning a series of automatic task set activations, or learning an integrated sequence that derives from 2 correlated streams of information. In the present study, our purpose was to distinguish among these 3 possibilities. In 4 separate experiments, we replicated and extended a previous study by Heuer, Schmidtke, and Kleinsorge (2001). The presence or absence of a sequence of tasks, as well as that of a sequence of different task-to-response mappings, was manipulated independently within experiments. Evidence of implicit sequence learning was found only when correlated sequences of tasks and mappings were present. No sequence learning effects were found when only a single task sequence or a single mapping sequence was present, even when the structure of the single sequence was identical to the structure of the integrated sequence of task-mapping combinations. These results suggest that implicit task sequence learning is not dependent on either perceptual learning of stimulus features or automatic task-set activation per se. Rather, it appears to be driven by correlated streams of information.     

The complexity of satisfiability for fragments of hybrid logic—Part I

The satisfiability problem of hybrid logics with the downarrow binder is known to be undecidable. This initiated a research program on decidable and tractable fragments.In this paper, we investigate the effect of restricting the propositional part of the language on decidability and on the complexity of the satisfiability problem over arbitrary, transitive, total frames, and frames based on equivalence relations. We also consider different sets of modal and hybrid operators. We trace the border of decidability and give the precise complexity of most fragments, in particular for all fragments including negation. For the monotone fragments, we are able to distinguish the easy from the hard cases, depending on the allowed set of operators.     

What shields some can shackle others: the approach‐related consequences of threat categorisations vary by agreeableness

It is common to think that threat categorisation tendencies (TCTs) should undermine a person's subjective well‐being. However, recent research has suggested that the hedonic impact of such tendencies varies considerably according to a person's traits. The present research seeks to extend such a perspective by considering potential interactions between TCTs and the trait of agreeableness. TCTs were measured through the use of choice reaction time tasks contrasting the threat and non‐threat categories. As expected, TCTs were not correlated with the trait of agreeableness, but interacted with this trait in predicting the dependent measures. Within three studies involving 184 undergraduates, TCTs were associated with the higher levels of approach‐related behaviour and positive emotion among disagreeable individuals, but lower levels of these same variables among agreeable individuals. The authors suggest that threat categorisation tendencies psychologically protect or burden the individual, depending on the levels of agreeableness. Copyright © 2005 John Wiley & Sons, Ltd.     

Naturally better? A review of the natural‐is‐better bias

People are frequently exposed to products and services that are labeled natural (e.g., Nature Made Vitamins or GoJo Natural Orange Hand Cleaner). The frequency with which this label is used suggests that it delivers an advantage in marketing and sales. Our review examines the preference for and perception of naturalness and reveals that people have a bias for items described as natural in many domains including foods, medicine, beauty products, cigarettes, and lighting. These preferences abound even when the natural item is identical or not objectively better than the non‐natural or synthetic item. We believe this bias may be driven by a natural‐is‐better default belief as well as the belief that natural items are safer than non‐natural items. Although a bias for natural items is apparent, this literature is in its infancy, and we suggest three areas that will help build and refine the empirical research base and theory: the measurement of behavior, the examination of individual differences, and the development of methods for reducing the bias. A better understanding of the naturalness bias relevant to these areas will lead to a more comprehensive understanding of the area, including factors that may cause and reduce it.