Hindsight bias describes the tendency of persons—after the outcome of an event is known—to overestimate their foresight. For example, following a political election, persons tend to retrospectively adjust their predictions to the actual outcome. These judgment distortions are very robust and have been observed in a variety of domains and tasks. About 50 years of research on hindsight bias have meanwhile brought a wealth of findings and insights. Core research questions are (1) how to explain hindsight bias in terms of underlying processes, (2) whether there are individual differences in susceptibility, (3) how the bias possibly impedes decision-making in applied contexts, such as political decision-making, and (4) how possibly to overcome it. Theoretical approaches suggest that there are distinct components of hindsight bias, and that several, mainly cognitive, mechanisms are responsible for them. Using stochastic models of hindsight bias allows us to estimate the relative proportions of these mechanisms. Depending on the task, motivational factors may also exert their influence. In addition, the strength of hindsight bias appears to be related to some personality traits and also to age. For example, some authors found that hindsight bias tends to increase with the tendency toward favorable self-presentation and to decrease with intelligence. Moreover, lifespan studies have shown that children and older adults show larger hindsight bias than young adults. Hindsight bias has been found in political decision-making (as well as in other applied domains). Surprisingly, attempts to overcome hindsight bias have mainly failed, whereas only a few debiasing techniques show promising results. In sum, one important conclusion is to be continuously aware of the potentially distorting influence of outcome knowledge on the evaluation of our own (or other’s) prior knowledge state.
Hindsight bias, outcome knowledge and adaptive learning
