Geri-Ellen Dow trying to bribe her 14-year-old son to do his summer reading. - 

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.

Ryssdal: So you heard me talking to Steven Levitt about the Freakonomics of paying kids to study, and what did you do? Tell me about your experiment.

Dow: I'm always looking for ways to motivate the kids because they don't seem to be really excited about school themselves.

Ryssdal: Shocking, shocking.

Dow: Yeah, it is. So I thought that, well my son had two books to read over the summer -- "Great Expectations" and "The Odyssey."

Ryssdal: So how much were you going to pay them?

Dow: So I figured $20 a book was reasonable.

Ryssdal: Oh man. See, I'm not going to read "The Odyssey" for $20.

Dow: Yeah, you know, as it turns out, he felt probably the same way as well.

Ryssdal: So tell me what happened.

Dow: So what happened was, he finished "Great Expectations" maybe four days ago, five days ago, and then he started "The Odyssey" two days ago. And I just have to point out that school starts tomorrow.

Ryssdal: So you're going to get your $20 back.

Dow: Well...

Ryssdal: No, are you give it to him? Come on.

Dow: He's 250 pages into it. And the hesitation was he seems to be plowing through it, which I don't understand how you can do that.

Ryssdal: Yeah, no. You're going to pro-rate this then, is this what I'm hearing you tell me?

Dow: We had a really heated discussion yesterday about whether I intended to pay him if he got it done before school or before the comprehensive test.

Ryssdal: Yeah, that's actually a very good point, which I should probably raise to Steven Levitt -- you've got to define the terms of the agreement.

Dow: Yes, and I was not clear on that. Although I think as it happened, and I had some different ideas about what I would have done if I was doing it over again.

Ryssdal: Like what?

Dow: Well I would have offered him more than $20.

Ryssdal: Yeah, you got that right.

Dow: For a 500-page book that was written 2,000 years ago.

Ryssdal: Now, Levitt and Dubner, the guys behind Freakonomics, would say, 'Well your sample size is a little small, and you need more information over time.'

Dow: So you think I should maybe have more kids and do it longer, is that what you're suggesting?

Ryssdal: No. Well, that's a personal choice actually. But really, you need to do the experiment over a longer period of time so you can have more data, more information, right?

Dow: And with more rigorous controls in terms of what the expectations are. Yes.

Ryssdal: Are you thinking you might do this again next summer? I guess you're going to wait and see how it goes, right?

Dow: Yes, I'm going to wait. I don't know. I don't know.

Ryssdal: This is so fun, you are clearly conflicted about this.

Dow: I am conflicted about it, yes.

Ryssdal: Huh. Well Geri, thanks a lot for your time.

Dow: All right, thank you Kai.

Follow Kai Ryssdal at @kairyssdal