Hindsight bias can be best summarized by the feeling you have after you learn an outcome of some event and thoughts such as "I knew that" or "I should have known that" start popping up in your consciousness. People are forced to make decisions daily and individuals can base their decision making on a wide variety of different experiences, emotions, heuristics, or even how the decision is framed. However the individual comes to make a decision, the hindsight bias occurs after the decision has already been made. After the outcome is known, the hindsight bias is the feeling that you get that tells you that you should have known the outcome. This phenomenon has breed phrases in popular culture such as "hindsight is 20/20" and similar sayings. Once the outcome is known then the tendency is for the individual to feel like they should have known the outcome all along when in fact the outcome is generally unknowable before the outcome manifests.
One example of this bias that I personally experience frequently occurs nearly every time I take a test. When I am taking a test in school, I answer all of the questions to the best of my ability. I used different decision making processes based on the question being asked such as making a recall from memory, using process of elimination, deductive reasoning, or even guessing in some cases. Despite the method I use for constructing an answer to a question, it represents my best effort at the time of taking the test. However, once I receive the graded test back, the answers that I answered incorrectly nearly always conjure up some immediate feelings. The feeling is something to the effect of "ah-ha" or "I knew that." Even though I really didn't know at the time of taking the test, once I got the graded test back I usually feel as if I should have. This is a common example of hindsight bias.
