Single, childless women are less happy, and it's due to genes

In the last post, General Social Survey data indicated that researcher Paul Dolan was wrong in claiming that single, childless women are happier than married women with kids.  In the old days, I would have focused, at least some, on the Durkheimian idea that social roles shape characteristics like one's level of happiness.  I was trained as a sociologist, and it has been my instinct to see social forces as important.

Years of study have convinced me that it is time to focus more on biological forces. The correlation between marriage and well-being need not be causal: people who are genetically happy might simply select themselves into marriage.  In fact, the correlations between marriage and a host of positives--greater financial success, mental and physical health, lower mortality, less risky behavior, less crime, and longer longevity--might be due to common genes which cause the correlations.

A study by Johnson et al. (2004) supports this idea.  Analyzing data on a sample of over 7,000 adults that included more than 2,500 twin pairs, they found that certain heritable traits predict marriage, and that much of the link between being married and being happy is due to genes. 

Specifically, they found the following traits for married versus single women: married women are more affectionate, nervous, careful, and traditional, and they feel like they are treated fairly by others. On the flip side, single women are less sociable, more risk-taking; they're calmer, more modern, and they think they are treated unjustly by others.

The profile of married men versus single men is very different: married men are cheerful, active, persistent, decisive, persuasive, aggressive, and traditional. They are less prone to fantasy, and they think that people treat them fairly.  Single men tend to be the opposite: They are sullen, indecisive, undisciplined, passive, modern, prone to fantasy, and they feel they are treated unfairly. 

All of these traits are strongly influenced by genes. According to the study, the heritability of being married is about .7, meaning that 70% of whether or not people are married is due to variation in genes.

So it looks like married people, especially men, tend to be happier because of their personalities. Affectionate, sociable women seek out marriage, and so do cheerful men who have the traits that lead to career success.  Married women seem drawn to comfort, security, and affection.  Men, in general, appear to be drawn to marriage, and the success-bound ones achieve it.

Single men and women are more modern, so they probably see marriage as less desirable, less expected, and both tend to be disagreeable. Single men might be less happy because they are less successful, and single women are more alienated, which is associated with sadness and mental health issues.  In addition, single women are risk-takers, and seem less drawn to the security and comfort of a permanent union.