There's always tons of interesting stuff in The Atlantic's "primary sources" section in the front of the book. It's kind of like a blog, but in a magazine. Except now, it's also on a website. At any rate, I thought this was a neat finding:
Alumni contributed $7.1 billion to higher education in 2004–05. The study reveals that graduates with children are about 13 percent more likely to give back to their schools and that they tend to give more as their children approach college age. But donations among this group decline after an admissions decision has been made—and plummet if their kids aren’t accepted. Though the authors note that alumni without a stake in the cycle still often give generously, many alums who are parents “believe that donations buy them entrance into a lottery whose prize is admissions for their children.”
It's completely intuitive, of course, but there's still need for proper research to confirm one's guesses about such things. Here's a link to the original paper “Altruism and the Child-Cycle of Alumni Giving,” by Jonathan Meer and Harvey S. Rosen.