Hindsight bias

The hindsight bias (English hindsight bias) describes the phenomenon in psychology that people do after they learn the outcome of events, systematically wrong remember their earlier predictions. They distort looking back their original estimates towards the actual outputs ( " outcomes" ). The effect means that people are no longer in a position after a ( major ) event, to assess the circumstances and reasons that led to the event as they did before the announcement of the event. They overestimate in retrospect much more systematically the possibility that one could have foreseen the event. The explanation is that the knowledge of the event changed the interpretation and evaluation of all related issues and thus shifts the entire cognitive " coordinate system " in the direction of his advocacy.

For example, a youth welfare office had a "conspicuous " family for years under observation, all trade regulations and service rules have been adhered to, nothing was formally failed. It is now known that the family has a child starve excruciating. Immediately comes in the context of public outrage to the question of how such a fact, despite the observation by the Office was possible. Right here now are not only the laity, but also experts for each area, the hindsight bias by looking at previously existing information under the influence of new event involves coming to an overestimation of the predictability of the event.

Especially in the attribution of blame and responsibility in many social, as well as in private areas of the hindsight -bias plays a role. It is important also to realize that kind of expertise can not compensate for this effect.

The phenomenon of Hindsight bias was first investigated in 1975 by Baruch Fischhoff at Carnegie Mellon University in Pittsburgh.

For easier measurement we used experimental designs ( operationalization ) in which a quantitative ( numerical ) detection is possible by letting appreciate metrics (eg election results ).

Research designs

There are two different research designs, the "memory design " and the " hypothetical design ".

The intra-individual " Memory Design"

A person is said to make a forecast of the probability of electoral victory by the party X before an election; calls, for example, 30 percent. After the election, the person is informed that the party has actually received 50 % of votes. Now one asks the person to remember the amount of their original estimate. Although 30 % was estimated, the person is convinced that she had typed to 40%. The difference to its original forecast is called hindsight bias. In the study, " Hindsight bias in political elections " by Blank, H., Fischer, V. & Erdfelder, E. ( 2003) for the first time a robust hindsight bias effect could be found. The authors used a memory design and chose the first time a longer interval of four months. In contrast to many previous studies, the time interval between the prediction of the election result and the memory of the prediction had been very low, which is why the results had not been very meaningful.

The inter-individual " hypothetical design "

Before an election you ask a group of people to a forecast. After the election, a second group of people is asked which election they had predicted. The difference between the two results reflects generally resist a hindsight bias.