On the etiology of internalizing and externalizing problem behavior: A twin-family study

Nikstat A, Riemann R. On the etiology of internalizing and externalizing problem behavior: A twin-family study. PLOS ONE. 2020;15(3): e0230626.Internalizing and externalizing behavior problems are established risk factors for many unpleasant outcomes and psychopathology in adulthood, and understanding the interplay between genes and environment is important for deducing implications for therapeutic interventions. Among genetic studies on internalizing and externalizing problem behavior, the heritability estimates differ widely. Most research only uses twin data and other-reports, and therefore certain limitations are inevitable. Our study is the first to investigate genetic and environmental influences on problem behavior using a Nuclear Twin Family Design and self-reports, in order to address these limitations. Internalizing and externalizing problem behavior of 3,087 twin pairs (age 11–23), a sibling, and their parents were analyzed with structural equation modeling to estimate heritability separately for each of three twin birth cohorts. Genetic influences account for about one-third of the variance for both internalizing and externalizing. Shared environmental influences were only found for internalizing, and through the advantages of considering data from the whole twin family, firstly could be identified as solely twin-specific. Our findings could contribute to a better understanding of the gap between heritability based on twin studies and DNA-based heritability (‘missing heritability problem’): Results indicate that heritability estimates gained via classic twin design and other-reports are slightly overestimated and therefore environmental influences, in general, are more important than previous research suggests. Simultaneously, we showed that family-specific environment either contributes to behavior problems only on an individual level, or that it has a lesser influence than originally thought

Robust Parsing of Cloned Token Sequences

Token-based clone detection techniques are known for theirscalability, high recall, and robustness against syntax errors andincomplete code. They, however, may yield clones that aresyntactically incomplete and they know very little about the syntacticstructure of their reported clones. Hence, their results cannotimmediately be used for automated refactorings or syntactic filtersfor relevance.This paper explores techniques of robust parsing to parse codefragments reported by token-based clone detectors to determine whetherthe clones are syntactically complete and what kind of syntacticelements they contain.This knowledge can be used to improve the precision of token-basedclone detection

The genetic and environmental effects on school grades in late childhood and adolescence

Eifler EF, Starr A, Riemann R. The genetic and environmental effects on school grades in late childhood and adolescence. PLOS ONE. 2019;14(12): e0225946.As academic achievement can have a major impact on the development of social inequalities we set out to explore how performance differences arise. Using data of the German twin study TwinLife, genetic and environmental effects on school grades in mathematics, German and the grade point average in two age cohorts (11 and 17 years old) were identified. Structural equation modelling on the data of 432 monozygotic and 529 dizygotic twin pairs as well as 317 siblings of the twins showed substantial genetic effects (up to 62%) in both cohorts on all three variables. Next to genetic influences, the twin-specific environment as well as non-shared environmental influences were found to explain the interindividual differences in mathematics and German as well as the grade point average. A cohort effect showing itself in higher heritability in the older cohort was found for mathematics and the grade point average but not for German. Moreover, we compared twins who were assigned to the same classroom to those twins who were assigned to different classrooms and found lower effects of the twin-specific shared environment in the latter group. Our study thereby contributes to the understanding of the etiology of interindividual differences in academic achievement in the numeracy and literacy domain in two age cohorts

Genetic analysis of cognitive failures (CFQ); A study of Dutch adolescent twins and their parents

A substantial part of the inter-individual variation in everyday cognitive failures in memory, perception and motor control can be attributed to genetic factors. Cognitive failures were assessed with the Cognitive Failures Questionnaire (Broadbent, Cooper, FitzGerald and Parkes, 1982) in a large sample of Dutch adolescent twin pairs and their biological parents. The heritability for CFQ scores was around 50 per cent. There was no association between CFQ scores and age or educational level. Both in the parental generation (aged 46 years on average) and in the o€spring generation (aged 17.7 years on average) women had somewhat higher mean CFQ scores than men. There were no sex di€erences in heritabilities. The part of the variance that could not be attributed to genetic factors was best explained by environmental in¯uences unique to the individual. There was no evidence for the in¯uence of shared environment on CFQ scores. CFQ scores of husband and wife were correlated (r ˆ 0.22) and this association was modeled as phenotypic assortment. The correlations between parents and o€spring were somewhat lower than the correlations between dizygotic twins. Under a model with equal heritabilities in parents and o€spring, there was some evidence that the genetic factors that in¯uence cognitive failures in the two generations are partly di€erent. # 1998 John Wiley & Sons, Ltd

Personality and attitudes towards current political topics

Riemann R, Grubich C, Hempel S, Mergl S, Richter M. Personality and attitudes towards current political topics. Personality and Individual Differences. 1993;15(3):313-321.We presented a representative list of 162 political issues currently discussed in Germany and the German NEO-FFI to 184 subjects (45% university students). Principal components analysis of the attitude items reveals four factors which are interpreted as (1) general conservatism, preference for authoritarian punitiveness, (2) social welfare and support of women's equality, (3) liberalism and affirmation of technological progress, and (4) affirmation of increase in taxation for environmental protection and the development of East Europe. The first unrotated factor is identified as general conservatism. The analysis of zero and higher order correlations shows meaningful relationships between political attitudes and personality dimensions. The highest (negative) correlations are found between openness to experience and conservatism. Age and sex effects on political attitudes are reported

Personality traits below facets: The consensual validity, longitudinal stability, heritability, and utility of personality nuances

It has been argued that facets do not represent the bottom of the personality hierarchy-even more specific personality characteristics, nuances, could be useful for describing and understanding individuals and their differences. Combining 2 samples of German twins, we assessed the consensual validity (correlations across different observers), rank-order stability, and heritability of nuances. Personality nuances were operationalized as the 240 items of the Revised NEO Personality Inventory (NEO-PI-R). Their attributes were examined by analyzing item residuals, controlling for the variance of the facet the item had been assigned to and all other facets. Most nuances demonstrated significant (p < .0002) cross-method agreement and rank-order stability. A substantial proportion of them (48% in self-reports, 20% in informant ratings, and 50% in combined ratings) demonstrated a significant (p < .0002) component of additive genetic variance, whereas evidence for environmental influences shared by twins was modest. Applying a procedure to estimate stability and heritability of true scores of item residuals yielded estimates comparable with those of higher-order personality traits, with median estimates of rank-order stability and heritability being .77 and .52, respectively. Few nuances demonstrated robust associations with age and gender, but many showed incremental, conceptually meaningful, and replicable (across methods and/or samples) predictive validity for a range of interest domains and body mass index. We argue that these narrow personality characteristics constitute a valid level of the personality hierarchy. They may be especially useful for providing a deep and contextualized description of the individual, but also for the prediction of specific outcomes

Veränderung individueller Einstellungsstrukturen

In einem vierjährigen Forschungsprojekt wurde im Rahmen eines 'natürlichen Experiments' untersucht, inwiefern sich Einstellungsänderungen aus grundlegenden alltäglichen Veränderungen des Verhaltens ableiten lassen. Der Beitrag stellt Ergebnisse der Längsschnittmessung bei Frauen, die ihr erstes Kind bekamen, und Männern, die ihren Wehrdienst leisteten, vor: Insbesondere geht es um die Veränderung individueller Einstellungsstrukturen in Bezg auf elf Interaktionspartner*innen und sich selbst

Wie können wir die Ursachen sozialer Ungleichheit verstehen?

Diewald M, Riemann R. Wie können wir die Ursachen sozialer Ungleichheit verstehen? In: Spinath B, ed. Empirische Bildungsforschung. Aktuelle Themen der Bildungspraxis und Bildungsforschung. Berlin Heidelberg: Springer Verlag; 2014: 68-78

On the genetic and environmental sources of social and political participation in adolescence and early adulthood

Kornadt A, Hufer A, Kandler C, Riemann R. On the genetic and environmental sources of social and political participation in adolescence and early adulthood. PLOS ONE. 2018;13(8): e0202518.Political participation (POP), social participation (SOP), and political interest (PI) are important indicators of social status and social inequality. Previous studies on related trait differences yielded genetic and environmental contributions. However, focusing on adult samples, classical twin designs, and convenience samples often restricts parameter estimation and generalizability, and limits the understanding of age differences. We investigated sources of variance in POP, SOP, and PI in late adolescence and early adulthood with an extended twin family design (ETFD). We analyzed data from over 2,000 representative German twin families. Individual environments not shared by family members reflected the major source of variance for all variables, but genetic influences were also pronounced. Genetic effects were mostly higher for young adults, whereas effects of twins’ shared environment were significant in adolescence. Our study deepens the understanding of the interplay between genetic and environmental factors in shaping differences in young persons’ integration in society