Monday, 11 April 2011

One reason I don't trust contingent valuation surveys

When faced with a thorny moral dilemma, what people say they would do and what people actually do are two very different things, a new study finds. In a hypothetical scenario, most people said they would never subject another person to a painful electric shock, just to make a little bit of money. But for people given a real-world choice, the sparks flew.

The results, presented April 4 at the annual meeting of the Cognitive Neuroscience Society, serve as a reminder that hypothetical scenarios don’t capture the complexities of real decisions.
Morality studies in the lab almost always rely on asking participants to imagine how they’d behave in a certain situation, study coauthor Oriel FeldmanHall of Cambridge University said in her presentation. But these imagined situations are missing teeth: “Whatever you choose, it’s not going to happen,” she said.

But in FeldmanHall’s study, things actually happened. “There are real shocks and real money on the table,” she said. Subjects lying in an MRI scanner were given a choice: Either administer a painful electric shock to a person in another room and make one British pound (a little over a dollar and a half), or spare the other person the shock and forgo the money. Shocks were priced in a graded manner, so that the subject would earn less money for a light shock, and earn the whole pound for a severe shock. This same choice was given 20 times, and the person in the brain scanner could see a video of either the shockee’s hand jerk or both the hand jerk and the face grimace. (Although these shocks were real, they were pre-recorded.)

When researchers gave a separate group of people a purely hypothetical choice, about 64 percent said they wouldn’t ever deliver a shock — even a mild one — for money. Overall, people hypothetically judging what their actions would be netted only about four pounds on average.

But when there was cold, hard money involved, the data changed. A lot. A whopping 96 percent of people in the scanner chose to administer shocks for cash. “Three times as much money was kept in the real task,” FeldmanHall said. When participants saw only the hand of the person jerk as it got shocked, they chose to walk away with an “astonishing” 15.77 pounds on average out of a possible 20-pound windfall. The number dipped when participants saw both the hand and the face of the person receiving the shock: In these cases, people made off with an average of 11.55 pounds.
Says Wired.

A person says he wouldn't shock people, not even for a lot of money, will jump at the chance when it's real money instead of hypothetical.

How much should you trust surveyed folks who say they'd be willing to pay lots extra to have "GE Free" foods?


  1. "How much should you trust surveyed folks who say they'd be willing to pay lots extra to have "GE Free" foods?"

    Here's an idea. Why doesn't somebody study the relationship between what people say about their willingness to buy GE Free foods and what they actually buy? You could survey people coming out of supermarkets, and check what they tell you against their docket from the supermarket.

    Sounds like a great idea!!! Wonder if its been done.

  2. Most opponents of GE know bugger all about it anyway, they have been sucked in by the paranoiad propaganda spread by the Green Party and co. The next time you're at the supermarket check the product labels of stuff you buy. If it says anything about containing soy products chances are it has at least some GE component; GE soy makes up something like 93% of the commercially grown soy in the US alone. (Source: Wikipedia) So kiwis are eating GM food every day and we're not seeing folk suddenly grow extra heads, turn funny colours, etc.

  3. It's going to be tough getting permission to make one of those hypothetical trolley problems into a real-world dilemma.

  4. How much should you trust surveyed folks who say they'd be willing to pay lots extra to have "GE Free" foods?

    According to Noussair, Robin and Ruffieux (2004) in The Economic Journal, not very much.

    They used an auction game with real money to work out the public's preferences for GE food in France. They discovered that, in a country where 79% of respondents stated that GE food should be illegal, only 35% of people were categorically unwilling to buy GE food, and 23% didn't even demand it be cheaper than non-GE food.