Naked self-promotion: the third edition of my book, Economics Is Everywhere (Worth Publishers), has just appeared. It contains little articles like those I have included on this blog (and, no doubt, some of the posts from this blog will be included in the fourth edition). I love many of the stories, but my all-time favorite from among the 700 that have been in the book’s various editions combines several basic economic ideas:

One of the students came up with what is perhaps the most amusing negative externality example that I have heard in my teaching career.

Her roommate is beautiful, but her roommate’s boyfriend, so she says, is very, very ugly. No problem, except that the roommate has a poster-sized photograph of the boyfriend on the wall on her side of the room, a poster that my student has to view whenever she is on her own side of the room.

I ask my student why, if the guy is so ugly, her roommate goes out with him, and she answers, “He goes to Harvard; and he’s also a very nice guy.” This illustrates the importance of human capital in the matching market that is dating, and also that looks aren’t everything, either. We also supply personality and the ability to get ahead, both of which are valued by the labor market and thus by potential spouses. Indeed, careful research shows that, compared with average-looking women, good-looking women marry guys with an extra year of education. Today, an extra year of education is associated with about an extra twelve percent annual earnings.