If the life sciences are to have much to say about politics, there needs to be a universal element to political orientations. In this essay, I argue that the recent prominence of nativist, law-and-order, populist politicians reveals the nature of this universal element. All social units have to address bedrock dilemmas about how to deal with norm violators and how welcoming to be to outsiders as well as to proponents of new lifestyles. Might differences on these core dilemmas be the universal element of political life? Using the followers of one of the most prominent examples of a nativist political leader—Donald Trump—as an example, I present data showing that Trump’s most earnest followers are different from others—even those who share their general ideological leanings—not on traditional economic or social issues, but rather on the group-based security issues that grow out of the bedrock dilemmas of social life.

Prior research finds that liberals and conservatives process information differently. Predispositions toward intuitive versus reflective thinking may help explain this individual level variation. There have been few direct tests of this hypothesis and the results from the handful of studies that do exist are contradictory. Here we report the results of a series of studies using the Cognitive Reflection Test (CRT) to investigate inclinations to be reflective and political orientation. We find a relationship between thinking style and political orientation and that these effects are particularly concentrated on social attitudes. We also find it harder to manipulate intuitive and reflective thinking than a number of prominent studies suggest. Priming manipulations used to induce reflection and intuition in published articles repeatedly fail in our studies. We conclude that conservatives—more specifically, social conservatives—tend to be dispositionally less reflective, social liberals tend to be dispositionally more reflective, and that the relationship between reflection and intuition and political attitudes may be more resistant to easy manipulation than existing research would suggest.

I extensively agree with Lieberman’s main argument and especially with his recommendations to graduate students and journal editors, which come at a critical time for our discipline’s development and future relevance. However, I depart from Lieberman on two issues. First, I argue that the research cycle is circular, and not teleological as Lieberman implies. For instance, randomized control trial (RCT) studies could be the start (and not the end) of a research cycle that leads to more descriptive and qualitative analysis in order to improve our understanding of causality. Second, I believe that the size of effects in RCT studies does matter, among other reasons because small effects might be symptoms of defective conceptualization of the main research problem.

Duarte et al. are correct that the social science enterprise would improve on several fronts if the number of politically conservative researchers were to increase; however, because they misunderstand the degree to which liberals and conservatives are dispositionally different, they fail to appreciate the full range of reasons that conservatives are reluctant to enter the modern social sciences.

Here we introduce the Genetic and Environmental Foundations of Political and Economic Behaviors: A Panel Study of Twins and Families (PIs Alford, Hatemi, Hibbing, Martin, and Smith). This study was designed to explore the genetic and environmental influences on social, economic, and political behaviors and attitudes. It involves identifying the psychological mechanisms that operate on these traits, the heritability of complex economic and political traits under varying conditions, and specific genetic correlates of attitudes and behaviors. In addition to describing the study, we conduct novel analyses on the data, estimating the heritability of two traits so far unexplored in the extant literature: Machiavellianism and Baron-Cohen's Empathizing Quotient.

Disputes between those holding differing political views are ubiquitous and deep-seated, and they often follow common, recognizable lines. The supporters of tradition and stability, sometimes referred to as conservatives, do battle with the supporters of innovation and reform, sometimes referred to as liberals. Understanding the correlates of those distinct political orientations is probably a prerequisite for managing political disputes, which are a source of social conflict that can lead to frustration and even bloodshed. A rapidly growing body of empirical evidence documents a multitude of ways in which liberals and conservatives differ from each other in purviews of life with little direct connection to politics, from tastes in art to desire for closure and from disgust sensitivity to the tendency to pursue new information, but the central theme of the differences is a matter of debate. In this article, we argue that one organizing element of the many differences between liberals and conservatives is the nature of their physiological and psychological responses to features of the environment that are negative. Compared with liberals, conservatives tend to register greater physiological responses to such stimuli and also to devote more psychological resources to them. Operating from this point of departure, we suggest approaches for refining understanding of the broad relationship between political views and response to the negative. We conclude with a discussion of normative implications, stressing that identifying differences across ideological groups is not tantamount to declaring one ideology superior to another.

A broad, multidisciplinary empirical literature reports that individual-level differences in psychology and biology map onto variation in political orientation. In our target article we argued that negativity bias can explain a surprisingly large share of these findings. The commentators generally support the negativity bias hypothesis but suggest theoretical and empirical revisions and refinements. In this response, we organize these proposals, suggestions, and criticisms into four thematic categories and assess their potential for furthering theories and empirical investigations of the bases for individual-variation in political ideology.

Political science is far behind the other social science disciplines in incorporating neurobiological concepts, techniques, and theory. In recent years progress has been made in closing this gap but many in the political science mainstream view the movement with concern or even horror. Though a healthy dose of skepticism is appropriate and beneficial to the scientific endeavor, negative reactions to viewing politics through a neurobiological lens are often based on fundamental misconceptions regarding both neurobiology and politics. In this Reflections essay, I address ten of these misconceptions, including the beliefs that biology is deterministic, reductionist, unnecessary, irrelevant, normatively dangerous, and ideologically biased. The goal is to encourage a constructive dialogue on the relevance of neurobiology to political life—a dialogue that would in turn improve research in the fledgling subfield and lead to innovations in political science by encouraging new ways of conceptualizing and analyzing the variables at the discipline's core.

Let me begin by thanking editor Jeff Isaac for inspiring and bringing to fruition this exchange. Securing the participation of nine academics and then cajoling us to meet deadlines and follow instructions is a remarkable accomplishment and I can only hope the finished product approaches his hopes for the enterprise. I would also like to thank the eight scholars who provided commentaries on my target essay. I am truly fortunate that such an all-star cast was willing to spend time pondering the role of neurobiology and politics. They assisted me in better understanding my own positions, and who can ask for more than that? I do not have the space here to offer the point-by-point response that their comments deserve, so I will instead concentrate on the two concerns that were raised most frequently: first, whether biological approaches can answer the kinds of questions political scientists should be asking, and second, whether, regardless of their value in answering questions, applying biological techniques to social behaviors leads to normatively unpalatable conclusions. Before addressing these two important matters, however, it is worth a moment to mention several areas of agreement.

Recently in this journal, Charney and English (2012) presented an extensive critique of candidate gene association studies using the widely noted Fowler and Dawes (2008) article on the relationship between self-reported voter turnout and both 5-HTT (serotonin transporter) and MAOA (monoamine oxidase A) as the driving example of their evaluation. Reanalysis of the Fowler and Dawes data by Charney and English, based on four critiques of candidate gene studies, led to the conclusion that neither polymorphism is related to variations in turnout. We add to this empirical debate by conducting an independent test using an original dataset containing 5-HTT data and two separate participation variables: self-reported participation and actual voting records. Our results confirm the original conclusions by Fowler and Dawes on 5-HTT, but also support several of the critiques suggested by Charney and English. We conclude by offering suggestions for the way candidate gene association studies should be interpreted by the discipline and processed by journal editors.

Recent research has found a surprising degree of homogeneity in the personal political communication network of individuals but this work has focused largely on the tendency to sort into likeminded social, workplace, and residential political contexts. We extend this line of research into one of the most fundamental and consequential of political interactions—that between sexual mates. Using data on thousands of spouse pairs in the United States, we investigate the degree of concordance among mates on a variety of traits. Our findings show that physical and personality traits display only weakly positive and frequently insignificant correlations across spouses. Conversely, political attitudes display interspousal correlations that are among the strongest of all social and biometric traits. Further, it appears the political similarity of spouses derives in part from initial mate choice rather than persuasion and accommodation over the life of the relationship.

The US House of Representatives underwent a series of reforms in the 1970s which, on paper, changed the institution in fundamental ways. Often, however, institutional inertia is able to transform important ‘paper’ changes into barely discernible actual changes. Have the reforms really led to alterations in the way Congress operates and the policies it produces? To provide a partial answer to this question, we single out one of the reforms – a change in the application of the seniority system in the selection of committee chairmen – and analyse it with an eye towards one hypothesized effect – alterations in the level of party support among key representatives. But by restricting our study in this manner, we are able to provide specific empirical facts which should be of considerable assistance in the important task of formulating more generalized conclusions about the ability of legislative reform to produce real change in the governing process.

The 1980 American national elections produced two highly salient and widely-discussed departures from past tradition. For the first time in forty-eight years, a previously elected incumbent president seeking re-election was defeated. At the same time the Republicans, the traditional minority party, seized control of the upper house. Both events figured heavily in discussions of the American electorate's supposed turn to the right. Much of this emphasis on ideological change may be misplaced. A third, although much less noted, departure from tradition also occurred in 1980: for the first time since 1932, real disposable per capita income declined in the year preceding a presidential election. The importance of such a decline for the electoral fate of an incumbent president has been well documented. Numerous previous studies have indicated a powerful and consistent impact of changes in economic conditions on voting behaviour in presidential elections. The influence of economic conditions on the fate of the president's party in House elections is also well-documented. In the case of Senate elections, however, the literature is curiously silent.

Beckwith and Morris raise concerns about the value of twin studies for understanding the role of genetics in complex human behavior, but virtually all of their concerns have been raised and rebutted before. When it comes to the equal environments assumption (EEA), the best approach is to test for and control possible violations of the EEA on heritability estimates rather than merely rejecting all empirical evidence because of the possibility of EEA violations. In many respects, since the study of the genetic basis of complex human behaviors now includes many methods in addition to twin studies, Beckwith and Morris's critique applies more to the behavioral genetics of a quarter century ago than to today's multifaceted behavioral genetics. Twin studies establish that there is a sizeable genetic component to political orientations, thereby giving cause to look further at the nature of that role by using other methodologies, including molecular genetics. We conclude by pointing out that the normative implications of the relevance of genes to human behavior are not nearly as worrisome as Beckwith and Morris seem to believe.

In the past, most political scientists have been oblivious to the growing empirical evidence challenging environmental determinism. Professor Charney, apparently as a result of the fact that genes and the environment interact in a complex fashion, advocates that this passive unawareness be replaced by active denial. Science, however, does not advance by avoiding important relationships merely because they are complicated and, fortunately, science is not heeding Charney's ideologically-based fears. Molecular geneticists, often working in tandem with political scientists, are quickly moving beyond twin studies to identify the specific suites of genes and biological systems that predict variation in core political preferences, whatever labels those preferences might be given in a particular culture at a particular time. We sympathize with the fact that our empirical findings, like those of so many behavioral geneticists, make Charney uncomfortable; still, his critique serves up nothing new—empirically or otherwise. Just as analyses of the roots of sexual preferences cannot presumptively ignore genetics, neither can analyses of the roots of political preferences.

We test the possibility that political attitudes and behaviors are the result of both environmental and genetic factors. Employing standard methodological approaches in behavioral genetics—specifically, comparisons of the differential correlations of the attitudes of monozygotic twins and dizygotic twins—we analyze data drawn from a large sample of twins in the United States, supplemented with findings from twins in Australia. The results indicate that genetics plays an important role in shaping political attitudes and ideologies but a more modest role in forming party identification; as such, they call for finer distinctions in theorizing about the sources of political attitudes. We conclude by urging political scientists to incorporate genetic influences, specifically interactions between genetic heritability and social environment, into models of political attitude formation.

In this article we propose that evolutionary biology can supply political science with a theory of the ultimate causes of human preferences and behaviors that it otherwise lacks. For the most part, political scientists are either unfamiliar with the social side of evolutionary theory or misidentify its key features. Far from being genetically deterministic or leading exclusively to predictions that all human behavior will be selfish, modern evolutionary theories stress that adaptive behavior is frequently characterized by a guarded sort of cooperation. We describe modern biological theory, offer our own version of it, discuss new and potentially useful interpretations of political attitudes and public policies, and present scientific evidence, drawn from research on autistic individuals and monozygotic and dizygotic twins, of the startlingly important role genetics plays in shaping politically relevant attitudes and behaviors.The authors are grateful to Chris Larimer, Levente Littvay, David Rapkin, Kevin Smith, Jeff Spinner-Halev, Elizabeth Theiss-Morse, and anonymous reviewers for their helpful comments and suggestions.