The Hindsight Bias:

Often people will make certain claims or judgments about a situation after they have seen it conclude.
Once a series of events plays out and one is aware of the outcome it is easy to exclaim: “oh yeah, I
knew it all along.” It is a common observation that events that took place in the past seem more
conceivable and more predictable than events that have not yet played themselves out.
In casual situations people often make judgments, attempting to foretell what they see as the outcome of
a given situation.  These predictions may be right or wrong but it is common for people to recall their
correct predictions and forget about the faulty ones.  This attempt to gain credibility can confuse the
speaker because it gives them an erroneous conception of probability and of their own ability to predict
random events.

Many psychological models of memory impairment attempt to explain how this type of cognitive error
might stem from a few different causal factors. Psychologists think that knowledge about the outcome of
an event might alter or erase previous memories related to the event before it played out.  This shows us
how volatile and delicate our memory really is.  Another possible causal factor for the hindsight bias is
related to cognitive distortion. Motivational factors and factors related to the heuristics used in recalling
events might make the original judgments less easy to activate.
The idea of hindsight bias was pioneered by B. Fischhoff. His Immediate Assimilation Hypothesis states
that the memory for original predictions is altered by the subsequent outcome of an event (Fischhoff,

Sporting events, for example, are often hotly debated. Sure enough, after the outcome of a game, or a
season there are many more people than is statistically probable that claim to have predicted the
outcome all along.

The dramatic fervor that fans display for their team is rekindled after a win but quickly ended and
forgotten about after a loss. Often when a situation is playing out an individual might throw in a quiet
remark about their prediction for a certain event. If they lose, the remark is forgotten, if they win they
can then speak vociferously about their “uncanny” prediction.

The hindsight bias, much like many of the phenomena described by psychologists, seems to many
people to be “common sense.” This view is influenced by the hindsight bias, the tendency to see things
as obvious, but only after the fact.  
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