Torture Supply Curves Slope Up

I suppose, when all things are considered, that is good news. From Wired:

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.)

The article is actually about how this result differs from cases where subjects are given similar hypothetical scenarios. To me, this is evidence in favor of relying on revealed preference approaches over surveys in social science.