A new study (which I can not find online yet) in The Journal of Politics has some interesting descriptive information on correlations between mates when it comes to politics:
On a scale of 0 to 1, where 1 means perfectly matched, physical traits (body shape, weight and height) only score between 0.1 and 0.2 among spouse pairs. Personality traits, such as extroversion or impulsivity, are also weak and fall within the 0 to 0.2 range. By comparison, the score for political ideology is more than 0.6, higher than any of the other measured traits except frequency of church attendance, which was just over 0.7.
The gap between physical traits and politics and religion was surprising to me, though I am not surprised by the power of politics and religion in sorting pairs. An important point of the paper apparently is that this correlation does not emerge through convergence over the term of a relationship. Rather, partners are strongly similar at the beginning of relationships. And the similarity isn’t simply due to the fact that they emerge out of a similar milieu where particular political and religious views are dominant:
Alford and his co-authors noted that sorting is not the only reason for spouses’ political uniformity, but it is clearly the most powerful. More traditional explanations for the political similarity of spouses turned out to have only modest effects and account for only about 10 percent of the similarity between long-term partners. Social homogamy — or the tendency for people to choose a mate from within one’s own religious, social, economic and educational surroundings — played only a small role.
There are some deeper issues at work here. I think for a fruitful relationship which lasts a couple needs a level of commensurability in their basic presuppositions, no matter the differences of detail. What are the ends of life? What is right and wrong? Particular political planks and orientations emerge out of this. People always say communication is important in a relationship, and that communication is made much more difficult when you have fundamental political or philosophical differences which make the other person difficult to grasp in terms of who they are at the core.
I couldn’t find spousal correlations of ideology in the GSS, but here is religion and educational attainment from 1990 to the present (the rows add up to 100%, so 66% of Jews have a Jewish spouse):
|< HS||HS||Junior College||Bachelor||Graduate||Total|
Remember that Jews are ~3% of the population. If mating was random 3% of the spouses of Jews would be Jews. As it is this underestimates the true count by a factor of 22. Even with non-religious people you have a factor of 4 inflation above what you’d expect (assuming ~10% of the population has no religion, though there’s some sex imbalance so unless you leave people single you’d expect some non-religious men to marry religious women). The inflation for people with graduate degrees is similar, 7.5% of the GSS sample has a graduate degree.
On a final note, we often make some assumptions or express curiosity when spouses are physically mismatched. But the data here indicates that this is much more common than a political mismatch. What if we could see a political mismatch? Would we make assumptions about what led a person to make the choice they did?