I'm sure you've witnessed this yourself: you see a couple in a heated political argument at a dinner party, at an event, or even a neighbor's house. You wonder: If they disagree so much about politics, why did they get together in the first place?
The bigger question here for researchers is understanding the extent to which these dynamics in a marriage or relationship influence one's political and social behavior. Intuitively, those who interact with you closely have some influence on how you think and act, politically and socially.
For decades, the predominant paradigm in the study of political behavior has been very individualistic. That is: Political scientists typically have thought of individual behavior as being shaped by larger forces, say, information gathered from newspapers, radio, television, or now the Internet. We have generally ignored the influences of those around us in our workplace and friendship networks. We have generally not studied, in depth, the influence of spouses or significant others on political behavior.
Part of the reason we have been so individualistic in our analyses of political behavior is theoretical, part of it is methodological. In particular, political scientists have (with some exceptions) been heavily wedded to the use of large-scale population surveys, and those surveys typically treat individuals as isolated from others, rarely asking about the attitudes and behaviors of other individuals in the network of the particular survey respondent.
Of course, this has been changing, as researchers have brought new theoretical and methodological tools to the study of political behavior. There is now a growing focus in the research literature on social and personal networks. I've written about some of this research in past essays (see, for example, "Genes and Social Networks").
But new research in this area is coming out quickly, and an excellent example is a paper by Alford, Hatemi, Hibbing, Martin and Eaves, "The Politics of Mate Choice", recently published in the Journal of Politics. Here is the paper's abstract:
"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."
More interestingly, their analysis indicates that among the political issues they studied, "Spouses are most likely to share views on hot-button social issues involving reproduction, religion, and sexual preference ... Attitudes on other political issues such as property taxes, foreign aid, immigration, federal housing, and censorship are much less concordant, displaying spousal correlations that are still positive but somewhat weaker."
This study has important implications. It provides additional evidence to the growing body of research showing that people may have a tendency to live with or marry, to reside by, and to interact with other people with similar political views. And it also indicates that if we want to understand how someone votes, we need to look beyond the opinions of the individual. We clearly need to look as well at the social and political networks that individuals interact with to understand their political opinions and behaviors.
And there are other implications as well. For example, we tend to associate with people who think like us, which means that our networks will tend to be homogeneous. That is, we tend to be in social and political networks with people who share --- not challenge --- our beliefs. Modern technologies like the diversification and narrowing of information sources (instead of a couple of news channels, we now have dozens on cable or satellite television), and the proliferation of narrowly cast information sources on the Internet (ideologically or politically focused blogs and websites) may now serve to reinforce our micro-behavior. It is possible that today's ideologically charged and politically polarized world might have its roots in the interaction between our micro-behavior and these macro-trends.