Arkes et al. (1981)

Doctors given a case history to read

Is it disease A or disease B?

Group 1 - told nothing about real diagnosis

Group 2 - told “correct” diagnosis was disease A

Group 3 - told “correct” diagnosis was disease B

Result: probability estimates were higher for

“correct” diagnosis

So: Hindsight Bias

•Hindsight bias happens when you warn people

to avoid it

•It does not happen when subjects don’t believe

the outcome information