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.
Excerpt from: 100 Things Every Designer Needs to Know About People (Voices That Matter) by Susan Weinschenk