From PhysOrg:
FeldmanHall’s study showed that what people say they will do in a given situation and what they really do are two very different things. If given a hypothetical situation of a choice of giving someone an electrical shock for money or walking away, most people answered they would never be able to inflict pain on another person. However, in a real-life scenario, with real money and real electric shocks, the actions were much different. In FeldmanHall’s study, subjects were placed in an MRI scanner and then given the choice to either administer an electrical shock to a person located in another room and make money (one British pound) or not inflict pain and receive no money. They also broke down that one pound into percentages based on the severity of the shock, so they would receive the full pound for administering a severe shock and less for more mild shocks.
The subject in the MRI was shown a video of the person receiving the shock and would either see just the person’s hand jerk or be shown both the hand jerk and the person’s face. Each participant was given the choice to shock another person 20 times, with the opportunity to make 20 pounds. In the hypothetical scenario, 64 percent of participants said they would never administer a shock to someone else for money. However, in the real world that number changed, and in a big way. When faced with real money, 96 percent chose to shock the person in the other room for money.
More here.
