The Power of Confirmation
Three scientists, Charles Lord, Lee Ross, and Mark Lepper, recruited forty-eight American undergraduates who either strongly supported the death penalty or strongly opposed it. They presented them with two scientific studies; one offered evidence regarding the effectiveness of capital punishment, and the other data showed its ineffectiveness. In reality, the studies had been fabricated. Lord, Ross, and Lepper had made them up, but the students did not know that. Did the students find the studies convincing? Did they believe that the data provided good evidence that should alter their minds? They did!
But only when the study reinforced their original view. Those students who strongly supported capital punishment thought the study that demonstrated its effectiveness was well conducted. At the same time, they argued that the other study was poorly executed and not compelling. Those who were originally against capital punishment assessed the studies the other way around. As a result, believers in the death penalty left the lab supporting capital punishment with more passion than ever, while those in opposition to it ended up opposing capital punishment with more zest than before.
Mark Lepper, David Greene, and Richard Nisbett (1973) conducted research on this question. They divided children into three groups:
- Group 1 was the Expected group. The researchers showed the children the Good Drawing Certificate and asked if they wanted to draw in order to get the certificate.
- Group 2 was the Unexpected group. The researchers asked the children if they wanted to draw, but didn’t mention anything about a certificate. After the children spent time drawing, they received an unexpected drawing certificate.
- Group 3 was the Control group. The researchers asked the children if they wanted to draw, but didn’t mention a certificate and didn’t give them one.
The real part of the experiment came two weeks later. During playtime the drawing tools were put out in the room. The children weren’t asked anything about drawing; the tools were just put in the room and available. So what happened? Children in the Unexpected and Control groups spent the most time drawing. The children in Expected group, the ones to had received an expected reward, spent the least time drawing. Contingent rewards (rewards based on specific behavior that is spelled out ahead of time) resulted in less of the desired behavior if the reward was not repeated. Later the researchers went on to do studies like this, with adults as well as children, and found similar results.