Bribing your kids to study: Does it work?

Marketplace:

Kai Ryssdal: I had a conversation a month or so ago with Steven Levitt about the Freakonomics of getting kids to get good grades. And how Levitt says we oughta just pay ’em. Fifty bucks for an A was what he got when he was a kid. Me: not one thin dime. But that’s a whole ‘nother story.
Anyway, Geri-Ellen Dow heard the segment and tweeted us a picture of two crisp $20 bills — one labeled “Great Expectations,” the other labeled “The Odyssey” — and a note saying the money was there for the taking by her 14-year-old son if he read the books in question.
So of course we had to call her up to see what happened. Geri, good to talk to you.
Geri-Ellen Dow: Thanks. It’s nice talking with you, Kai.