The controversy surrounding the cost of Dan Ariely's Hershey's Kiss

For some time I've been trying to figure out how best to express my annoyance—is annoyance the right word? I think it is—at the ever-growing group of books that seek to use social science research to explain how people often don't act in their own economic self-interest. It's not that I think research by psychology PhDs isn't a useful way to gain insight into why we make economic "mistakes." On the contrary, I think such research is extremely useful as a way to understand, for instance, the tendency of people to pay a lot of attention to introductory interest rates on credit cards while practically ignoring the much-more-relevant post-teaser rate. What I find incredibly irritating is the incessant recycling of the same few experiments, especially by journalists, consultants and the like who obviously have no respect for the complexity and nuance of academic research. If I have to read one more hack explanation of Kahneman and Tversky's 35-year-old paper on cognitive biases, I am going to scream.

So I am indebted to Janet Maslin for pointing out, in this morning's New York Times, the very interesting case of the 1-cent Hershey's Kiss. Two new books, by journalists Chris Anderson and Ellen Ruppel Shell, talk about an experiment by Duke University's Dan Ariely, a man whose PhDs include one in cognitive psychology. The descriptions unfold differently, but the gist is this: when given the option between a cheap yet crappy chocolate*, and a slightly-more-expensive but delicious chocolate, people will pay more for better candy. At least until the crappy chocolate goes from costing 1 cent to being free. At that point, a whole lot of people switch and eat the crappy chocolate, even though the difference in price in inconsequential. The conclusion: when things are free, we act irrationally.

Maslin takes major issue with inconsistencies between Anderson's and Shell's accounts of the experiment. Was the better chocolate a Ferrero Rocher hazelnut or a Lindt truffle? Was its price 26 cents or 15? Maslin concludes that "neither author is entirely to be trusted"—although, oddly, doesn't tells us which description is right or what accounts for the inconsistency.

So let me pick things up there. Let me reach up to my bookshelf and take down Dan Ariely's book, and reread Chapter 3, "The Cost of Zero Cost." As it turns out, the explanation is quite simple: Ariely ran the experiment a bunch of different times, tweaking the set-up in each instance, in order to make sure the result was robust. That, of course, is lost in the pop retelling.

I, more than most, understand how tempting it can be for journalist-types to write about such experiments. In fact, when I reviewed Ariely's book, Predictably Irrational, I mentioned the Hershey's Kiss experiment. Er, make that the Hershey's Kiss experiments. I didn't go into the nuance of multiple trials, either. And writing for a lay audience, I think that's fine. I'm not as put-off as Maslin is by the Anderson-Shell variation in specifics.

What I do worry about, though, is that as social science experiments more broadly become the stuff of best-selling books, important instances of nuance—those caveats that say things like this experiment only applies in a limited set of circumstances—are lost. That in an effort to further a particular thesis, pop writers ignore the inconvenient details that any self-respecting academic wouldn't be quick to discard.

In a way, that cat is long since out of the bag. Malcolm Gladwell built an entire career on reading social-science journals, after all. And surely there is utility that the journo-types bring. Gladwell's Blink is the 39th best-selling book on Amazon. The man whose lifework provides the basis for much of that book, German psychologist Gerd Gigerenzer, wrote a book, too: it's at 57,707. Gigerenzer's ideas have made it farther, to more people, to a broader audience, because of Gladwell—a journalist who knows how to package and market.

All I'm saying is, let's be knowing when we look at these books. There are a lot of entirely useless me-too books in this genre; let's feel free to ignore those. And as for the ones that do have interesting ideas translated from the social sciences—well, let's keep in mind that even if a conclusion is valid, the presentation you're getting in a book on the front table at Barnes & Noble isn't likely to be the most accurate in the world.

Barbara!

*Apologies to the good people at The Hershey Company. I like your products—but I think even you know what I'm saying here.