At its best, political psychology uses well-grounded theories from psychology to help explain the origins and dynamics of political behavior. Accounting for individual differences in political attitudes, skills, and behaviors is a central focus of this enterprise. Due in part to the previously bewildering state of personality theories in psychology, political scientists have largely left personality out of models of political behavior. Personality has been used by some researchers who study elite behavior, or it makes an appearance in some studies via single traits like authoritarianism or dogmatism. Many political scientists who have not been paying close attention would be surprised to find out that much of contemporary personality research has converged on a single model—the five factor or Big Five model. The model's name comes from its central organizing principle: Variations in personality can be adequately described by five core traits—extraversion, emotional stability (neuroticism), conscientiousness, agreeableness, and openness to experience. In Personality and the Foundations of Political Behavior, Jeffery Mondak shows how modern personality theory, in the form of the Big Five model, can add to our understanding of a wide range of political orientations and behaviors.

Mondak has written a book that should be read by those both familiar and unfamiliar with modern personality theory. For the latter, it would be hard to find a more accessible and comprehensive introduction to theory and research on the Big Five model. The first three chapters of this book set out the core arguments for incorporating personality into the study of political behavior, discuss the theoretical foundations of the Big Five model and a great deal of research that has used it, and show how the traits can be measured with a battery of questions short enough to fit on most survey instruments. Chapter 2 takes the reader through the history of the Big Five model, evidence of its possible genetic origins, and the characteristics and major correlates of each of the five traits. Many review papers on the Big Five written by psychologists do not present this material so clearly.

Chapters 4 through 6 present Mondak's empirical contribution to the study of personality and political behavior. Those who are more familiar with research on personality will want to scrutinize these chapters closely. The author presents the results of analyses that show the effects of the Big Five traits on political knowledge and discussion, political orientations and ideology, and participation. Many of the results come from multiple data sets, thus providing evidence of the robustness of these effects. Impressively, a number of the coefficients in these chapters are substantively large; many of the marginal effects are comparable to any other determinants of these variables. And it is refreshing to see that in many cases, Mondak has specified models that go beyond simple linear, additive effects of personality. In particular, there are several demonstrations of strong interactions between pairs of personality traits or between a trait dimension and some aspect of the political or social environment.

One of the notable characteristics of this book is Mondak's careful approach to both the conceptual underpinnings of personality and the empirical analyses. Although the author is clearly enthusiastic about the potential contributions of personality to the study of political behavior, he presents a balanced picture that discusses both the utility of this approach and its limitations. Indeed, it is difficult to identify potential criticisms of the use of the Big Five model in political science that he has not mentioned somewhere in this book. I do want to note a few concerns that should be considered alongside his largely positive presentation.

Mondak, along with others who are using the Big Five model, suggests that personality, and the Big Five model in particular, may provide the link between genes and political attitudes. The argument is based on two conclusions from twin studies: There seems to be a significant genetic component to both political attitudes and the Big Five traits. So it is possible that the prepolitical personality traits are the intervening factor between genes and political attitudes. That is certainly a plausible argument but it is, at the moment, just a conjecture. One problem is that many traits—including things like authoritarianism, “traditionalism,” and religiosity—have similarly high estimated genetic components. It is not clear that the heritability of the Big Five distinguishes them from many other traits that could be mediating factors. In a direct test of this assumption, a forthcoming article (Brad Verhulst, Peter Hatemi, and Lindon Eaves, “Correlation not Causation: The Relationship Between Personality Traits and Political Ideologies,” American Journal of Political Science) fails to find any evidence for such a direct mediating role of personality.

It is also easy to assume that if a trait has a sizable genetic component, then that must arise out of a direct biological connection, that is, variations in some neurotransmitter or the size of a specific brain structure. Consider, though, one intriguing finding on the origins of extraversion: A sizable fraction of the variance in this trait is a function of physical attractiveness and strength (Aaron Lukaszewski and James Roney, “The Origins of Extraversion: Joint Effects of Facultative and Calibration and Genetic Polymorphism,” Personality and Social Psychology Bulletin 37 [March 2011]: 409–21). Since attractiveness and strength are highly heritable, some of the heritability of extraversion could be a result of social adaptation to physical characteristics. This suggests a very different understanding of the biological significance of personality for political behavior.

As Mondak clearly notes, despite the convergence in the psychological literature on a five factor model of personality, the appropriate number of trait dimensions for understanding political attitudes and behavior is an open question. The problem with settling too quickly on just five traits is well illustrated by a recent article on the effects of one Big Five trait—agreeableness—on ideology (Jacob Hirsh et al., “Compassionate Liberals and Polite Conservatives,” Personality and Social Psychology Bulletin 36 [May 2010]: 635–64). Mondak, like other researchers, finds no significant effect of agreeableness on ideology. Distinguishing two subdimensions of this trait, Hirsh and his colleagues show that compassion is positively related to liberalism, while politeness is negatively related. Working at the higher-order trait level obscures these relationships.

One of the most interesting aspects of the empirical findings in this book is the nonadditive relationships that Mondak demonstrates. I could not help but wonder, however, how many other researchers would choose to look for those particular interactions. More generally, what is missing from these analyses is a theoretical framework for linking personality to political behavior. Most of the relationships that Mondak demonstrates are quite reasonable. People high on extraversion should have larger social networks and more discussion partners. How can we go beyond such commonsense models of personality effects?

It is unreasonable to expect anyone to write a book at this point in time that answers all of these questions. Personality and the Foundations of Political Behavior is a major contribution to the political behavior and political psychology literature. It deserves to be read by anyone who is interested in the origins of individual differences in political attitudes and behavior. Mondak's clear presentation of this approach and its limitations should leave the reader cautiously enthusiastic about the future of this research enterprise.