Clever Hans fooled lots of examiners who weren't expecting a fraud, but the facts came out when better experiments were designed. Hans couldn't count or do arithmetic, and he got the same wrong answers as his owner.
ESP fooled lots of people who were expecting frauds but had no experience in experimental design, or who were not expecting frauds and did not control for them.
ESP fooled lots of people who were expecting frauds but had no experience in experimental design, or who were not expecting frauds and did not control for them.