Genes, personality, and political behavior: A replication and extension using Danish twins.

In this article, we examine whether there is genetic overlap between personality traits and political participation, interest, and efficacy. We make several contributions to the literature. First, we use new data from a large sample of twins from Denmark to examine the link between genes, the Big Five traits, and political behavior. Previous research in this area has not examined the Danish context. Second, because our measures have some overlap with those used in previous studies, we are able to examine whether previous findings replicate in a different sample. Finally, we extend the literature by examining the possible genetic link between some personality and political traits that have not yet been explored. Overall, we find that genes account for a fairly large share of the correlation between two of the Big Five personality traits (openness and extraversion), political participation, and political interest. Thus, most of the relationship between these personality traits and our measures of political behavior can be accounted for by a common underlying genetic component.

Using deep learning to predict ideology from facial photographs: expressions, beauty, and extra-facial information.

Deep learning techniques can use public data such as facial photographs to predict sensitive personal information, but little is known about what information contributes to the predictive success of these techniques. This lack of knowledge limits both the public's ability to protect against revealing unintended information as well as the scientific utility of deep learning results. We combine convolutional neural networks, heat maps, facial expression coding, and classification of identifiable features such as masculinity and attractiveness in our study of political ideology in 3323 Danes. Predictive accuracy from the neural network was 61% in each gender. Model-predicted ideology correlated with aspects of both facial expressions (happiness vs neutrality) and morphology (specifically, attractiveness in females). Heat maps highlighted the informativeness of areas both on and off the face, pointing to methodological refinements and the need for future research to better understand the significance of certain facial areas.

Parent Contributions to the Development of Political Attitudes in Adoptive and Biological Families.

Where do our political attitudes originate? Although early research attributed the formation of such beliefs to parent and peer socialization, genetically sensitive designs later clarified the substantial role of genes in the development of sociopolitical attitudes. However, it has remained unclear whether parental influence on offspring attitudes persists beyond adolescence. In a unique sample of 394 adoptive and biological families with offspring more than 30 years old, biometric modeling revealed significant evidence for genetic and nongenetic transmission from both parents for the majority of seven political-attitude phenotypes. We found the largest genetic effects for religiousness and social liberalism, whereas the largest influence of parental environment was seen for political orientation and egalitarianism. Together, these findings indicate that genes, environment, and the gene-environment correlation all contribute significantly to sociopolitical attitudes held in adulthood, and the etiology and development of those attitudes may be more important than ever in today's rapidly changing sociopolitical landscape.

The personalities of Danish MPs: Trait- and aspect-level differences.

OBJECTIVE: We study personality traits of Danish parliamentarians (MPs) and examine elite-voter congruence and elite differentiation. Whereas previous political elite studies have focused only on the Big Five level, we include aspect-level differences. METHOD: In a highly representative survey of Danish MPs (N = 81; response rate = 46.3%) and a representative study of Danish voters (N = 3,612), we used the 60-item NEO-PI-R short version to examine personality differences on the Big Five level and, based on the NEO-BFAS, the aspect level. RESULTS: MPs were more extraverted, conscientious, and open than the average voter. On the elite level, liberal MPs were more agreeable and, on the aspect level, more compassionate but not more polite than conservative MPs. MPs in center parties had stronger power aspirations and were less agreeable and more extraverted than MPs in peripheral parties. On the aspect level, MPs in center parties were more assertive and enthusiastic and less polite. Conscientiousness and Agreeableness were associated with power aspiration, but Extraversion was not because the assertiveness effect was suppressed by a non-effect for enthusiasm. CONCLUSIONS: The inclusion of the aspect level explains null findings at the Big Five level and adds important nuances to the personality portrait of political elites.

Genetic influences on political ideologies: twin analyses of 19 measures of political ideologies from five democracies and genome-wide findings from three populations.

Almost 40 years ago, evidence from large studies of adult twins and their relatives suggested that between 30 and 60% of the variance in social and political attitudes could be explained by genetic influences. However, these findings have not been widely accepted or incorporated into the dominant paradigms that explain the etiology of political ideology. This has been attributed in part to measurement and sample limitations, as well the relative absence of molecular genetic studies. Here we present results from original analyses of a combined sample of over 12,000 twins pairs, ascertained from nine different studies conducted in five democracies, sampled over the course of four decades. We provide evidence that genetic factors play a role in the formation of political ideology, regardless of how ideology is measured, the era, or the population sampled. The only exception is a question that explicitly uses the phrase "Left-Right". We then present results from one of the first genome-wide association studies on political ideology using data from three samples: a 1990 Australian sample involving 6,894 individuals from 3,516 families; a 2008 Australian sample of 1,160 related individuals from 635 families and a 2010 Swedish sample involving 3,334 individuals from 2,607 families. No polymorphisms reached genome-wide significance in the meta-analysis. The combined evidence suggests that political ideology constitutes a fundamental aspect of one's genetically informed psychological disposition, but as Fisher proposed long ago, genetic influences on complex traits will be composed of thousands of markers of very small effects and it will require extremely large samples to have enough power in order to identify specific polymorphisms related to complex social traits.

Heritability in political interest and efficacy across cultures: Denmark and the United States.

Interest in politics is important for a host of political behaviors and beliefs. Yet little is known about where political interest comes from. Most studies exploring the source of political interest focus on parental influences, economic status, and opportunity. Here, we investigate an alternative source: genetic transmission. Using two twin samples, one drawn from Denmark and the other from USA, we find that there is a high degree of heritability in political interest. Furthermore, we show that interest in politics and political efficacy share the same underlying, latent genetic factor. These findings add to the growing body of literature that documents political behaviors and attitudes as not simply the result of socialization, but also as part of an individual's genetically informed disposition.

The Danish political twin study: political traits in Danish twins and the general population.

We compare a recent Danish twin survey on political attitudes and behaviors to a nationally representative survey covering similar topics. We find very similar means and variances for most of our constructed scales of political attitudes and behaviors in the two surveys, although even small differences tend to be statistically significant due to sample size. This suggests that the twin study can be used to make inferences on the heritability of several political traits in the Danish population.