On the psychology of experimental surprises.

Studies of the psychology of hindsight have shown that reporting the outcome of a historical event increases the perceived likelihood of that outcome. Three experiments show that similar hindsight effects occur when people evaluate the predictability of scientific results—they tend to believe they knew all along what the experiments would find. However, the hindsight effect was reduced by forcing people to consider how the research could otherwise have turned out. Implications for the evaluation of scientific research by lay observers are discussed.