As laypeople who read about science in newspapers and blogs, we’re often interested in results. Did the mice develop cancer? Sometimes, though, it’s not the results which offer the most food for thought, but the methods. How do you make a mouse smoke a cigarette?
A new study in the Journal of Human Capital offers a nice example of what creative methods can do. The economist Gustaf Bruze studies how people select spouses. Not too surprisingly, people tend to select spouses with similar education levels: high school graduates marry other high school graduates, Ph.Ds marry other Ph.Ds.
Why? One possible explanation is proximity to similar folks. People spend a lot of time at school and at work. In both places, they’re very likely to meet people with education levels similar to their own. A different explanation is desire for financial stability. People might select a spouse whose education suggests that he or she will be a good provider.
It’s important to pinpoint the correct explanation because this marriage pattern has implications for social equality. People with higher education levels make more money. If they only marry peers with similar education levels, that money doesn’t move to other sectors of society.
To sort out these competing explanations, we need a method for examining what people do when neither proximity and financial stability matters. But that’s a real problem. Almost everyone works with colleagues who have similar education levels. And almost everyone’s income is related to their education.
Bruze came up with a creative solution. He studied movie actors. They differ from the rest of us in two key ways. One difference is proximity to similar folks. Movie actors don’t meet a homogenous group of people at work; instead, they meet a diverse group with a variety of education levels. (They also tend not to meet their spouses at school). The second difference concerns financial stability. Crucially, unlike most of us, movie actors do not earn wages that correlate with their formal education.
So Bruze analyzed data from 280 actors in the U.S. movie industry and got the following result. Movie actors marry movie actors with similar education levels — just like the rest of us! This suggests that neither proximity nor financial stability explains the marriage pattern. It seems, instead, that people simply have an inherent preference for spouses with similar education levels.
Bruze’s result may not surprise you much. Do people prefer similar people as spouses? Yes, they do. But his methodology should stimulate some creative thinking. How do you make a person take a spouse whose education suggests they won’t be a good provider? You don’t. Instead, you study someone who has already done so.
Scientific American: Movie star couples share educational backgrounds
Live Science: Want to marry a movie star?
Freakonomics: What can movie stars tell us about marriage and education?
ScienceNewsOnline: What can movie stars tell us about marriage?
Bruze, Gustaf. 2010. New evidence on the causes of educational homogamy. Department of economics, Aarhus University.
Clip art from Educational Technology Clearinghouse