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. In an era of reduced public support and increased public scrutiny of scientific research, psychologists are under increasing pressure to make certain that their work is viewed as both important and informative. The lay test of importance is typically some aspect of personal or social relevance. The test for informativeness is some variant of the questions Did I learn anything new from this research? or Did the results surprise me? Relevance judgments are, of course, a highly individual matter. Assuming that a project has been properly explained, scientists have little basis professionally for reproving an individual who believes that the problem was not worth the resources invested in it. However, when an observer claims that the results of a study were highly predictable—and thus the study need not have been conducted—there may be grounds for contention. Recent results by Fischhoff Support for this research was provided by the