Satoshi Kanazawa

The Scientific Fundamentalist

Marriage

Men do everything they do in order to get laid IV

Why does marriage settle men down?

Posted Aug 01, 2008

There is something else that crime and genius have in common.  Just as age does, marriage depresses both tendencies.

Criminologists have long known that criminals tend to “settle down” and desist (stop committing crime) once they get married, while unmarried criminals continue their criminal careers.  But criminologists tend to explain this phenomenon from the social control perspective pioneered by the criminologist Travis Hirschi (the same Hirschi of the team who first discovered the age-crime curve).  Social control theorists argue that marriage creates a bond to the conventional society, and investment in this bond, in the form of a strong marriage, makes it less likely that the criminal would want to remain in the criminal career, which is incompatible with the conventional life.  Men must therefore desist from crime when they get married in order to protect their investment in conventional life; in Hirschi’s language, married men develop a “stake in conformity.”  Marriage also increases the scope and efficiency of social control on the criminal.  Now there is someone living in the same house and monitoring the criminal’s behavior at all times.  It would be more difficult for the criminal to escape the wife’s watchful eye and engage in illicit activities.

The social control explanation for the effect of marriage on desistance from crime makes perfect sense, until one realizes that marriage has the same desistance effect on perfectly legal, conventional activities, such as science.  A comparison of the “age-genius curve” among scientists who were married at some point in their lives with the same curve among those who never married shows the strong desistance effect of marriage on scientific productivity.  Half as many (50.0%) unmarried scientists make their greatest contributions to science in their late 50s as they do in their late 20s.  The corresponding percentage among the married scientists is 4.2%.  The mean age of peak productivity among the unmarried scientists (39.9) is significantly later than the mean peak age among married scientists (33.9).

Given that the Nobel Prize for scientific achievement didn’t exist in the ancestral environment, the evolved psychological mechanisms of men appear to be rather precisely tuned to marriage as a cue to desistance.  Nearly a quarter (23.4%) of all married scientists make their greatest scientific contribution in their career and then desist within five years after their marriage.  The mean delay (the difference between their marriage and their peak productivity) is a mere 2.6 years; the median is 3.0 years.  It therefore appears that scientists rather quickly desist after marriage, while unmarried scientists continue to do important scientific work.  When you remember that great scientific discoveries usually require many years of cumulative and continued research, the near coincidence of the male scientists’ marriages and their desistance (after which they cease to make any greater scientific discoveries) is remarkable.  Another study by the sociologists Lowell L. Hargens, James C. McCann, and Barbara F. Reskin also demonstrates that childless research chemists are more productive than their colleagues with children.

You may think that unmarried scientists continue to make scientific contributions much later in their lives because they have more time to devote to their careers.  Unmarried and therefore childless scientists do not have to spend time taking care of their children, driving them back and forth between soccer practices and ballet lessons, or doing half the household chores, and that is why unmarried scientists can continue making great contributions to science while married scientists must desist to devote their time to their families.  This is precisely Hargens et al.’s interpretation of the negative association between parenthood and productivity among research chemists.

However, I would point out that almost all the scientists in my data on scientific biographies lived in the 18th and 19th centuries, when married men made very little contribution in the domestic sphere and their wives did not have their own careers.  Hargens et al.’s data come from 1969-1970, when this was probably still true to a large extent.    If anything, married scientists probably had more (rather than less) time to devote to science, because they had someone to take care of their domestic needs at all time.

Why, then, does marriage depress the productivity of all men, criminals and scientists alike?  What underlies the desistance effect of marriage?  I’ll explain in my next post.