Hindsight Bias – is when you know the outcome of some process and you are overconfident that you would have predicted it. Even if you would educate people that they have hindsight bias this doesn't change their overconfidence. This is connected to
Experiment. You ask people to predict the outcome of some unfamiliar historical event, in which there are four potential outcome (the real experiment was based on a conflict between Gurkhas and British in 1814). 1) Victory A, 2) Victory B, 3) Deadlock without peace, 4) Deadlock with peace. And you have five groups. One that you don't tell what outcome have happened. And four others you are telling each different version of what have happened. In the table below there are real answers on what they declared they would answer. I marked on red the highest number in each column. Result: if you are gonna be told the outcome you will think you would have predicted it.
Situation | Outcome 1 prediction | Outcome 2 prediction | Outcome 3 prediction | Outcome 4 prediction |
---|---|---|---|---|
Not told outcome | 33.8% | 21.3% | 32.3% | 12.3% |
Told Outcome 1 | 37.3% | 14.3% | 15.3% | 13.4% |
Told Outcome 2 | 30.3% | 38.4% | 20.4% | 10.5% |
Told Outcome 3 | 25.7% | 17.0% | 48.4% | 9.9% |
Told Outcome 4 | 33.0% | 15.8% | 24.3% | 27.0% |
Alternative name: “I would have known this bias”


If you read the answer to the question you will overestimate your ability to being able to know the answer to this question if you wouldn’t know it
Consider a study in which volunteers were shown some quiz-show questions and asked to estimate the likelihood that they could answer them correctly. Some volunteers were shown only the questions (the question-only group), while others were shown both the questions and the answers (the question-and-answer group). Volunteers in the question-only group thought the questions were quite difficult, while those in the question-and-answer group—who saw both the questions (“What did Philo T. Farnsworth invent?”) and the answers (“The television set”)—believed that they could have answered the questions easily had they never seen the answers at all. Apparently, once volunteers knew the answers, the questions seemed simple (“Of course it was the television—everyone knows that!”), and the volunteers were no longer able to judge how difficult the questions would seem to someone who did not share their knowledge of the answers.