The Study of Personality Architecture and Dynamics (SPeADy): A Longitudinal and Extended Twin Family Study

Kandler C, Penner A, Richter J, Zapko-Willmes A. The Study of Personality Architecture and Dynamics (SPeADy): A Longitudinal and Extended Twin Family Study. Twin Research and Human Genetics. 2019;22(6):1-6.AbstractThe Study of Personality Architecture and Dynamics (SPeADy) is a German research project that aims to investigate the sources of interindividual differences in intraindividual personality development. The main focus lies in the dynamic interplay between more stable core characteristics and more environmentally malleable surface characteristics, as well as between personality and life experiences over time. SPeADy includes a twin family study encompassing data from 1962 individuals (age: 14–94) of 682 families, including 570 complete twin pairs (plus 1 triplet set), 327 parents, 236 spouses and 145 children of twins. Data collection started in 2016 and data from the first wave are currently obtainable as open source. Available data comprise a broad range of personality variables, such as personality trait constructs, motives, interests, values, moral foundations, religiosity and self-related concepts. For the currently ongoing second wave of data collection, we added retrospective reports on major life events. Special features of this genetically informative study are the extended twin family data and its longitudinal design. Three assessment waves in 2 years’ intervals are planned until 2022. In this article, we briefly describe the design and contents of the SPeADy twin family study as well as some recent findings, future plans and open science issues.</jats:p

Do sojourn effects on personality trait changes last? A five-year longitudinal study

Richter J, Zimmermann J, Neyer FJ, Kandler C. Do sojourn effects on personality trait changes last? A five-year longitudinal study. European Journal of Personality. 2020;35(3):358-382.This study examined sojourners’ long-term personality trait changes over five years, extending previous research on immediate sojourn effects. A sample of German students (N = 1,095) was surveyed thrice (T1-T3) over the course of an academic year. Sojourners (n = 498) lived abroad shortly after T1 for one or two semesters, stayers (n = 597) remained in their home country. Five years after T1, we surveyed the same participants (n = 441, 40.3%) again (T4). Beyond substantial selection effects, latent neighbor-change models revealed that small differences between sojourners’ and stayers’ openness, agreeableness, and neuroticism changes occurred early after sojourn-induced contextual change. Model estimates suggested sustained sojourn effects on openness and neuroticism changes thereafter, and a reversed effect on agreeableness change after return. Due to reduced power and low accuracy at T4, these estimates were not statistically significant. Based on model comparison analyses, however, we could rule out reversed effects for openness and accentuated effects for agreeableness and neuroticism as least likely. Moreover, separating short-term and long-term sojourners revealed no substantial differences, but recurring sojourn experiences tended to play a role in sustaining differences. We discuss implications for future studies on patterns of sojourn effects on personality trait changes

Spectral error bounds for Hermitian inexact Krylov methods

We investigate the convergence behavior of inexact Krylov methods for the approximation of a few eigenvectors or invariant subspaces of a large, sparse Hermitian matrix. Bounds on the distance between an exact invariant subspace and a Krylov subspace and between an exact invariant subspace and a Ritz space are presented. Using the first bound we analyze the question: if a few iteration steps have been taken without convergence, how many more iterations have to be performed to achieve a preset tolerance. The second bound provides a measure on the approximation quality of a computed Ritz space. Traditional bounds of these quantities are particularly sensitive to the gap between the wanted eigenvalues and the remaining spectrum. Here this gap is allowed to be small by considering how well the exact invariant subspace is contained in a slightly larger approximated invariant subspace. Moreover, numerical experiments confirm the applicability of the given bounds

Backward error analysis of an inexact Arnoldi method using a certain Gram Schmidt variant

In numerous recent applications including tensor computations, compressed sensing and mixed precision arithmetics vector operations like summing, scaling, or matrix-vector multiplication are subject to inaccuracies whereas inner products are exact. We investigate the behavior of Arnoldi's method for Hermitian matrices under these circumstances. We introduce a special purpose variant of Gram Schmidt orthogonalization and prove bounds on the distance to orthogonality of the now-not-anymore orthogonal Krylov subspace basis. This Gram Schmidt variant additionally implicitly provides an exactly orthogonal basis. In the second part we perform a backward error analysis and show that this exactly orthogonal basis satisfies a Krylov relation for a perturbed system matrix -- even in the Hermitian case. We prove bounds for the norm of the backward error which is shown to be on the level of the accuracy of the vector operations. Care is taken to avoid problems in case of near breakdowns. Finally, numerical experiments confirm the applicability of the method and of the proven bounds

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

Integrating Autonomous Busses as Door-to-Door and First-/Last-Mile Service into Public Transport: Findings from a Stated Choice Experiment

Autonomous busses and on-demand (OD) services have the potential to improve the public transport system. However, research on potential traffic impacts is still ongoing, mainly because of a lack of existing use cases of autonomous driving as part of public transport. The availability of revealed preference data for mode choice decisions is thus very limited. Therefore, we conducted a stated choice experiment to assess mode choice preferences with regard to use cases as the main mode of transport and as the solution for the first and last mile. We also distinguished between OD and schedule-based (sched.) services. The target population of the survey is the population of Baden-Württemberg, a state in southwestern Germany. The responses of 1,434 people were analyzed using a nested logit approach. On this basis, we established exemplary utility functions and descriptively derived recommendations for efficient forms of deploying autonomous busses in addition to already existing well-developed public transport systems. It was found that, under the given conditions, public transport pass owners without a car in their household would be the most interested in using autonomous busses. Car owners without a smartphone see less benefit. It was also shown that the recruiting method of the respondents is crucial. Those reached via social media were significantly more positive than those contacted via an online panel. Further evaluations show that autonomous busses are rated similarly to existing public transport and consequently have particularly high potential on medium distances, especially if their deployment leads to shorter access routes

KINETIC AND KINEMATIC COMPARISON OF ALPINE SKI RACING DISCIPLINES AS A BASE FOR SPECIFIC CONDITIONING REGIMES

The purpose of this preliminary case study was to compare the alpine ski racing competition disciplines slalom and giant-slalom with respect to principal kinematics of the lower limbs and the acting forces. Knee angles and ground reaction forces of one high level athlete were determined using inertial sensors and pressure insoles, respectively. Slalom was characterized by a “high dynamic skiing mode” with a distinct “knee angle and loading synchronism” between the inside leg and the outside leg. For giant slalom, a polarized situation was observed: “higher quasi static loads at high knee angles” on the outside leg and “lower eccentric-concentric loads at low knee angles” on the inside leg. These findings may help to increase the specificity of conditioning training and developing more discipline-specific exercises

The Genetic Foundations of Attitude Formation: The Case of Left-Right Political Orientations

Kandler C, Bell E, Shikishima C, Yamagata S, Riemann R. The Genetic Foundations of Attitude Formation: The Case of Left-Right Political Orientations. In: R. A. S, S. M. K, eds. Emerging Trends in the Social and Behavioral Sciences: Interdisciplinary Directions. In Press.Since the pioneering work of Eaves and Eysenck (1974) appeared in Nature some 40 years ago,psychologists, sociologists, political scientists, and behavioral geneticists have investigated the effects of nature and nurture on the formation of social attitudes. It has consistently been found that manifestations of social attitudes (i.e., preferences, values, and beliefs pertaining to things like politics, religion, the treatment of ingroups and outgroups, etc.) are genetically influenced. More recently, researchers have focused their efforts on the psycho-physiological pathways between gene activity and attitudes. In particular, a broad body of research examines how personality traits may be a link between genetic factors and political orientations. The latter are typically treated as either a single left-right dimension or divided into two core aspects: resistance to change/authoritarian conservatism and acceptance of inequality/social dominance orientation. In this article, we provide an overview of this research, present some findings from our recent international behavioral genetic study on the topic, and identify key issues for future research. We suggest that future studies treat attitude formation as a complex process in which genetic factors and the psycho-physiological phenomena that stem from them are affected by the surrounding social environment and culture. Such research will require: (1) international study designs capturing individual and cultural levels of variation; and: (2) interdisciplinary collaboration among scientists and researchers in various fields of study such as genetics, psychology, sociology, political science, neuroscience, and human biology

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