#twinstudy — Public Fediverse posts
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DATE: September 10, 2026 at 07:00AM
SOURCE: PSYPOST.ORG** Research quality varies widely from fantastic to small exploratory studies. Please check research methods when conclusions are very important to you. **
-------------------------------------------------TITLE: Family environments shape authoritarian traits differently than dominance preferences
Genetic predispositions and family environments both shape extreme political views, but they do so in entirely different ways depending on the specific type of attitude. A new study reveals that a desire for social conformity is heavily influenced by household upbringing, while a preference for group dominance stems more from outside personal experiences. The research was published in Behavior Genetics.
Political scientists and psychologists often examine two distinct personality traits to understand polarized socio-political attitudes. The first is Right-Wing Authoritarianism. This concept describes a person’s preference for strict adherence to social conventions, collective security, and obedience to authority.
The second concept is Social Dominance Orientation. This captures a person’s desire for group-based hierarchies and the belief that their own social group is inherently superior to others. Both traits reliably predict prejudice, support for extreme political movements, and a tolerance for discrimination.
Researchers want to know why people develop these distinct views in the first place. Past research has shown that both biological genetics and life experiences play a role in shaping them. It has remained largely unknown whether the specific environmental and genetic sources differ between the two traits.
Psychologists Christian Kandler and Jana Instinske of Bielefeld University in Germany, along with sociologist Edward Bell of the University of Western Ontario, wanted to map exactly how these influences combine. They also aimed to see if the roots of these political attitudes shift as people grow from adolescence into young adulthood.
The researchers analyzed data from a large study of 1,440 German families. This group included identical and fraternal twins, their parents, and their non-twin siblings, encompassing more than 5,000 individuals. The twins belonged to three distinct age cohorts averaging 15, 21, and 27 years old.
Participants answered survey questions designed to measure their levels of both authoritarianism and social dominance. By comparing the attitude similarities between identical twins, who share all their genes, and fraternal twins, who share about half, the team could estimate the mathematical contribution of genetics.
Adding parents and non-twin siblings to the analysis allowed the researchers to account for the specific environments families create. It also let them measure assortative mating. This is the well-documented tendency of people to marry partners who share similar political and social views.
The results showed that genetics shape about the same total amount of variance for both personality traits. The genetic components themselves differed slightly in their structure. Authoritarianism was influenced by both additive genetics, which are straightforward traits passed directly from parents, and nonadditive genetics, which involve complex interactions between different genes.
Social dominance was driven entirely by additive genetic factors. Beyond that basic genetic contribution, the two political orientations diverged completely in their environmental origins. Authoritarianism showed a strong connection to family inheritance and upbringing.
The data indicated that parents who favor social conformity tend to choose partners who feel the same way. These parents then pass down both genetic predispositions and a home environment that reinforces those exact traditionalist views. Researchers refer to this combined biological and environmental inheritance as a passive genotype-environment correlation.
In this scenario, children receive genes that might make them lean toward conformity, and they are simultaneously raised in a household that actively promotes obedience and tradition. Social dominance showed almost no link to this kind of passive family inheritance.
The tendency for parents to match with partners based on dominance preferences was lower, and the home environment played a negligible role in shaping the trait in their children. Instead, a person’s preference for group hierarchy was heavily shaped by their own unique, individual experiences outside the family home.
The researchers suggest this divergence makes sense based on what the traits represent. Authoritarianism involves moral regulation and conformity, which are central to keeping a family unit cohesive. Because these values dictate household rules and religious traditions, they heavily influence mate selection and parenting.
By contrast, a preference for social dominance usually applies to intergroup competition in the broader outside world. A belief in societal hierarchy is less relevant to daily household dynamics, making it less likely to be directly programmed by the family environment.
The team also looked at how these influences changed as the twins aged. They initially suspected that the impact of the family environment would fade as adolescents grew into adults and selected their own surroundings. They hypothesized that genetics would play a larger role as adults sought out social circles and news sources that matched their natural predispositions.
Instead, the data pointed in the opposite direction. For both traits, the total genetic influence remained relatively stable across the age groups. The influence of environments shared specifically by the twins actually increased from adolescence to adulthood.
This twin-specific shared environment was essentially nonexistent for 15-year-olds but became highly relevant for 21-year-olds and 27-year-olds. The researchers suspect that as young adults become eligible to vote, they might engage in more political discussions with their peers and twin siblings. This co-development process could amplify shared social influences during the exact years when political identities solidify.
A few limitations shape how these findings should be interpreted. The study compared different age groups at a single point in time, rather than tracking the same individuals across their entire lives. This makes it difficult to separate genuine developmental changes from generational effects related to the specific time period in which a given cohort was born.
The statistical tests did not yield statistically significant differences between the age cohorts for many of the mathematical model parameters. The researchers note that an even larger sample might be needed to confirm other age-related trends. The study also relied on relatively short survey measures, which can sometimes limit the precision of personality evaluations.
Additionally, the mathematical models required the researchers to assume that genetic and environmental variances remain identical across different generations, which may not perfectly reflect reality given shifting cultural norms. Understanding these origins provides a foundation for making sense of political polarization.
The study, “Sources of Differences in Right-Wing Authoritarianism and Social Dominance Orientation from Adolescence to Adulthood: A Multi-Cohort Twin Family Study,” was authored by Christian Kandler, Jana Instinske, and Edward Bell.
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#psychology #counseling #socialwork #psychotherapy @psychotherapist @psychotherapists @psychology @socialpsych @socialwork @psychiatry #mentalhealth #psychiatry #healthcare #depression #psychotherapist #RightWingAuthoritarianism #SocialDominanceOrientation #PoliticalAttitudes #TwinStudy #FamilyEnvironment #GeneticsAndPolitics #PassiveGenotypeEnvironmentCorrelation #AssortativeMating #PoliticalPolarization #BehaviorGenetics
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DATE: September 1, 2026 at 04:00PM
SOURCE: PSYPOST.ORG** Research quality varies widely from fantastic to small exploratory studies. Please check research methods when conclusions are very important to you. **
-------------------------------------------------TITLE: Genetic evidence confirms ADHD symptoms cause poorer academic performance in kids
Children who display more symptoms of attention-deficit/hyperactivity disorder (ADHD) tend to earn lower grades in school, and new research provides evidence that these symptoms directly cause poorer academic performance. By applying advanced genetic models to data from twins and siblings, scientists found that ADHD symptoms negatively affect grades, while grades do not appear to influence the severity of ADHD symptoms. The study was published in Behavior Genetics.
Attention-deficit/hyperactivity disorder, or ADHD, is a common neurodevelopmental condition characterized by persistent patterns of inattention, hyperactivity, and impulsivity. These symptoms are highly heritable, meaning that the condition is strongly influenced by genetics. For years, scientists have observed that children with more ADHD symptoms tend to struggle academically. However, determining whether the symptoms directly cause poor school performance or if other shared factors are to blame has been a difficult task for researchers.
In medical science, the ideal setup for establishing cause and effect is a randomized controlled trial. But assigning children to experience mental health symptoms is ethically and practically impossible. To get around this, researchers often use a technique called Mendelian randomization. This method uses genetic variations as a stand-in for the exposure of interest, like ADHD. Because genes are assigned randomly at birth, they are less likely to be influenced by environmental factors that might confuse the results.
But Mendelian randomization has its own weaknesses. One major issue is horizontal pleiotropy, a scenario where a genetic variant influences the outcome through entirely different biological pathways, rather than just through the condition being studied. If a gene associated with ADHD also independently affects how a child learns, the results could be skewed. To address this problem, the authors of the current study combined genetic tools with data from twins and siblings. This approach allowed them to test the direction of the effect between ADHD symptoms and school grades while filtering out the noise of shared family environments and complex genetic overlap.
The research, led by Luis F. S. Castro-de-Araujo of Virginia Commonwealth University, utilized data from the Adolescent Brain Cognitive Development Study. This large-scale, long-term project tracks the development of thousands of children across the United States. For this analysis, the team focused on 1,523 twin and sibling pairs, as well as some individual children, during the third year of the study’s follow-up.
To measure ADHD symptoms, the researchers used a standard questionnaire called the Child Behavior Checklist, which was completed by the children’s caregivers. The caregivers also reported the children’s school grades from the previous year. Additionally, the researchers calculated polygenic risk scores for the participants. A polygenic risk score is a single number that estimates a person’s genetic likelihood of developing a specific trait based on millions of small genetic variants. In this case, the team calculated scores for both ADHD liability and educational attainment, focusing on a subsample of 1,071 children of European ancestry because the reference genetic data available was limited to that population.
The researchers fed these measures into a series of complex statistical models designed for twin data. The most advanced of these models allowed the team to look at causation in both directions at once. They could see if ADHD symptoms reduced grades and if low grades worsened ADHD symptoms, all while accounting for shared genetics, shared home environments, and horizontal pleiotropy.
The analysis provided evidence that ADHD symptoms have a direct, negative effect on a child’s school grades. When looking at the reverse direction, the researchers found that school grades did not have a statistically significant effect on ADHD symptoms. The team also tested whether these patterns differed between boys and girls. Despite ADHD being diagnosed more frequently in boys, the mathematical models showed that the negative effect of the symptoms on academic performance was consistent across both sexes.
The findings are in line with research covered by PsyPost in 2023, which found that higher ADHD symptoms were associated with lower educational attainment across adolescence. In that earlier Dutch study, academic achievement was evaluated through secondary school educational track placement rather than caregiver-reported grades, but both studies point to similar academic hurdles for youth dealing with ADHD symptoms.
As with all research, there are some caveats to consider. First, the data for the third year of the study was collected during the COVID-19 pandemic. The disruptions to daily life and schooling during this period might have affected the grades reported by caregivers, potentially introducing extra noise into the data.
Another thing to keep in mind is the measurement of the symptoms themselves. The questionnaire completed by caregivers is a highly reliable research tool, but it is not the same as a formal clinical diagnosis of ADHD made by a medical professional.
The study’s reliance on genetic data from people of European ancestry also limits how broadly the findings can be applied. Because comprehensive genetic reference data for other populations is currently lacking, the researchers could only run their most advanced causal models on a specific subset of the participants. Future research will need to include diverse genetic data to ensure these findings apply to all populations. The authors also suggest that future studies track individual children over longer periods to see how symptom persistence influences academic performance as they grow older.
The study, “ADHD and Student Grades in Children from the ABCD Study®: A Twin and Siblings Study,” was authored by Luis F. S. Castro-de-Araujo, Daniel Zhou, Mei-Hsin Su, Sydney Kramer, Robert Loughnan, and Michael C. Neale.
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#psychology #counseling #socialwork #psychotherapy @psychotherapist @psychotherapists @psychology @socialpsych @socialwork @psychiatry #mentalhealth #psychiatry #healthcare #depression #psychotherapist #ADHD #ADHDsymptoms #academicperformance #grades #genetics #twinstudy #Mendelianrandomization #Education #ChildDevelopment #BehaviorGenetics
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#Jyväskylänyliopisto'n porukat osoittavat, että iäkäs terve > liikunta, ei toisinpäin. Liikunta on hyväksi, kohtuudella, eikä liikkumattomuus iäkkäänä ole synti. Interesting.
Tein väitöskirjan samasta #kaksostutkimus'aineistosta. Se on eräs hienoimpia ja parhaiten hyödynnettyjä tutkimuksiamme: vahvuudet erinomainen suunnittelu ja datan laadun valvonta. #twin #twinstudy #genetics #ageing #physicalactivity #liikunta #ikä
https://www.medrxiv.org/content/10.1101/2023.06.02.23290916v1.full.pdf
https://thl.fi/en/web/thl-biobank/for-researchers/sample-collections/twin-study