The education gradient is that the better educated you are, the more likely you are to behave in ways that preserve your health, and the longer you are likely to live. For example, a person with a year of additional schooling is 3.0% less likely to smoke, and for that reason will be slightly less likely to develop cancer, cardiovascular disease, and many other health problems. Now, 3.0% may not seem like much, but keep in mind that years of schooling vary a lot across the population, meaning that the health-behavior-related health differences between those who do not finish high school and those with professional degrees are significant.
I wrote about this last week, in response to an article by David Cutler and Adriana Lleras-Muney (Journal of Health Economics 29 (2010) 1–28), who wanted to know why education predicts health-related behaviors. They reported data that they interpreted as showing that
education seems to influence cognitive ability, and cognitive ability in turn leads to healthier behaviors. As best we can tell, the impact of cognitive ability is not so much what one knows, but how one processes information.
There may be something to this, but keep in mind that:
- Education increases cognitive ability, but cognitive ability also influences how much education you get.
- 'Cognitive ability' is itself a sort of black box with many components, and it is not clear which components help you take better care of your health.
In this post, I want to raise a different concern about Cutler's claim. I think that highly educated people take better care of their health, in part, because they are selected into social niches that promote better health behavior.
On the one hand, an educated person takes better care of her health because her abilities take her into social networks comprised of people who take better care of their health. The effects of social networks on behavior are HARD to estimate, but it can be done. Jason Fletcher (Health Economics 19: 466–484 (2010)) finds that "increasing the proportion of classmates who smoke by 10% will increase the likelihood an individual smokes by approximately 3%".
On the other hand, the workplaces that you get access to with an education select for better health behavior, directly or indirectly. Serious substance abuse disorders are rare where I work, not because my colleagues are 'better' people, but because it is really hard to get into medicine or science with that kind of disability.
In the story I am telling here, cognitive ability still plays a critical role. But the story isn't just that processing information more effectively allows you to 'get' that smoking causes cancer. Rather, cognitive ability gets you access to a social niche that strongly reinforces good health behavior. Taking better care of your health, in turn, amplifies your advantages in competing for jobs. A virtuous circle... but only for those on the upward spiral.