You can conduct a whole career as a research psychologist without venturing outside the lab. (Heck, with online studies, you don’t even have to put on pants.) But Uri Gneezy and John List are known for their field experiments, testing hypotheses in the real world. Last year they published a book, The Why Axis, that reveals a bundle of counterintuitive findings in areas such as health care, education, crime, and discrimination. I thought I’d share a few of them, along with links to relevant papers.
Note that the book doesn’t just rattle off findings, as I’m about to do, but shares the human stories and drama behind their field experiments—for example, List calling one of his associates a “wimp” for not getting out of the car to recruit a subject in a rough part of Chicago. (The subject? A young girl named Gabriella with the chance to attend an experimental and life-changing preschool.)
1. Fines (and rewards) can backfire.
When day care centers started charging a $3 fine for parents who picked their kids up 10 minutes late, delayed pickups increased drastically. The fee changed the meaning of lateness from a social imposition to a convenience that can be purchased (inexpensively). In another study, kids collected less charity for a cause when they received a monetary bonus for their efforts. They no longer thought of the task as altruism, but as a low-paying job. “So,” the authors write, “the moral of the story is to either pay enough, or don’t pay at all.”
2. A temporary reward can change behavior permanently.
When college students were paid $100 to go to the gym eight times in a month, they were still twice as likely as other students to be going to the gym after the payment period ended. They’d gotten over the hump of starting a routine.
3. Men are not more competitive than women everywhere.
A game was devised in which the player tries to throw tennis balls into a bucket. A player can choose to win money for each point, or to compete and win money by outscoring another player. In the United States and among Masai villagers, about twice as many men as women chose to compete. But among the matrilineal Khasi people in India, more women than men competed. “For the Khasi, nurture is king—or queen, as the case may be,” the authors write. Matrilineal societies have other differences. In a public-goods game, men and women among the Khasi invested more in the group than did people in the neighboring village of Assamese. “When women have stronger economic influence, the society becomes more consensual and public-spirited.”
4. Women can be nudged to compete.
A job was advertised on Craigslist, saying, in some cases, that the payment was "$17.60," and in others, "$17.60 and negotiable." In the first case, men were much more likely than women to negotiate on payment; in the second, women were slightly more likely. The second ad also cut the gender gap in applicants in half.
5. Payment increases test scores.
When inner-city kids were told right before a test that they could earn money if their test scores improved over their last score, their scores increased 5 to 10 percentile points. “It showed that an important part of the racial achievement gap was not due to knowledge or ability, but simply to the students’ motivation while taking the test,” the authors write.
6. You can elicit more donations by conveying less need.
Letters were mailed asking for donations to a cause, saying the cause had already raised 10%, 33%, or 67% of its goal. As standard practice, charities say they’re at 33%, but 67% worked best. Instead of donors thinking they could free ride on others’ contributions toward a nearly-completed goal, they preferred to follow the leader, thinking a cause must be good if it’s doing well.
7. Opt-out checkboxes increase donations.
Checkboxes were added to some Smile Train mailings that let a donor report, “This will be my only gift. Please send me a tax receipt and do not ask for another donation.” This once-and-done letter raised about twice as much money, from more donors—and donations from this group did not decrease afterward. Offering a choice to opt out was basically a gift to the recipient, encouraging a gift in return. Entering people in a raffle also increases donations, for the same reason, and those donations increase after the raffle is over.
The studies in this book focus on people’s motives—for studying, or competing, or helping—but in the end, the book is a long argument for empiricism, in any domain. The authors' parting words: “Experiment! Go out—white coat and pen-protector are not required—and find out what’s really going on.”