According to this Wall Street Journal article:
"Male Mets fans were 43% more likely than Yankees fans to drink beer. They also drink more in general … [but] have better support systems: they rated higher for marriage (51%) and pets (47%). By contrast, the typical male Yankees fan is unmarried (59%), owns no pets (58%), and is less likely to have children in his home. 'The Yankees are more like that because they really don't care, they just care about winning,' said Michael Dawkins, a Mets fan from Brooklyn. 'They don't have time to focus on the other things in life.'"
The study also finds: "Men who follow the Mets are slightly more likely to have stopped their education during or just after high school (30% versus 25%), but there's no great income disparity." Prima facie evidence that the Mets fans - earning about the same despite lesser education, drinking more, and caring less about winning - must have, on average, higher IQs?