Home > Attention, Memory, Metacognition > I knew it! The effect of hindsight bias and why you probably did not actually know it.

I knew it! The effect of hindsight bias and why you probably did not actually know it.

There is a cold crispness to the air, but the sun in the cloudless sky gives you the little bit of warmth you need to feel comfortable. It is an early November day, and it is time for the U-12 soccer championship. Maybe you are a player, a parent, a friend, even a referee here today. There are four teams here with the same goal in mind, to win all their games so that they get crowned champion. The Cheshire Rams are the ones you are hoping to win today. You do not know how the day is going to go because all of the teams here have had great records this season and are all very competitive for the title. Hours later, the Cheshire Rams have done it. They are champions! You are in the car riding back, and all you can think to yourself is “wow, I knew it would happen!”



What is Hindsight Bias?

Did you actually know that the outcome would happen as it did? The truth is, most likely not. Looking back, it may feel as if you did, but that is only because it was after the fact. This is a phenomenon known as Hindsight Bias. This bias is something that can affect many aspects of our daily lives. Maybe you did not study well enough for an exam and you thought you would do poorly, but get it back and end up doing well and think to yourself “oh I knew I would do just fine”. Perhaps you just went out on a date and gave someone your number and are hoping they will contact and they don’t, but then a week later you get a message from them and think “I knew he’d text me eventually”. This bias has been studied with many decision making and betting tasks. It has also been described in medical diagnosis, political events, athletic competitions, economic decisions, and more. Clearly it is something that affects many aspects of our lives and it is important to understand how it so easily manifests itself and what we can do to change that.

Why do we experience Hindsight Bias?

In a study done by Roese and Vohs, they address the factors that contribute to why we experience hindsight bias; giving insight on how we can avoid it when there are serious repercussions, such as extreme overconfidence or misjudgments that can lead to medical malpractice. To begin with, they argue there are three main aspects to hindsight bias. The first is memory distortion, then inevitability, and finally foreseeability (Roese 2012). People may first misremember something, and then perceive the actual event to be inevitable, and finally believe that they could have foreseen the outcome. Previous research has shown that we selectively recall information that supports what we know to be true, thus explaining a major that contributes to this bias and three main aspects that Roese describes. In a similar manner, confirmation bias occurs when one interprets events that are biased towards pre-existing beliefs and expectations (see http://web.colby.edu/cogblog/2017/04/17/3310/ for further discussion on this bias). Both of these biases are related to the fact that memory is reconstructive; we remember the important aspects of an experience but only later on piece them together to form the memory. Reconstructive memory describes how several cognitive processes, such as perception, semantic memory, beliefs and expectations, and more influence memory recall. Clearly, how we piece things together and what pieces we actually remember might favor what we wanted or expected to happen and not what really happened.




Furthermore, other research also looked at the specific factors that cause hindsight bias. A key argument is that metacognitive experiences are a crucial aspect to the cause of hindsight bias (Sanna 2006). Metacognition describes the ability to reflect on your own level of knowledge and thought process (if you are interested in learning more about metacognition, visit https://cft.vanderbilt.edu/guides-sub-pages/metacognition/). If we are not able to accurately reflect on how we think and what we truly remember, it can be hard to recognize what is real and what is not. Attention may also influence this ability, as it is hard to remember the details of events if you were not attending to them because you did not find them important at the time. Attention and metacognition are clear factors involved in experiencing hindsight bias.

What problems does Hindsight Bias cause?

There can be several downsides to hindsight bias depending on the person and context. One overarching idea is that we are not able to learn from previous experiences very well, for example when we are over-confident and do not realize that we actually were making significant misjudgments. A specific example of not recognizing this over-confidence and misjudgment involves the case of a radiologist and the evidence used by the prosecution. Berlin (2000) describes the case of a man who came to see a radiologist after developing symptoms but was told his scans were fine. Three and a half years later the man came in only to find out he had a massive tumor and died within the next year. The radiologist was brought to court. The prosecuting attorney had statements from professional radiologists saying that the beginnings of the mass were very clear in the original scans, but the problem was they were aware and knew what to look for in that circumstance. The defense attorney focused on the issues of frequency of perceptual errors among radiologists and the influence of hindsight bias to these prosecuting statements. The paper referenced other evidence supporting that hindsight bias is indeed a problem with radiologists. The jury did find the radiologist guilty, even though evidence showed that hindsight bias was present in this situation (Berlin 2000). This shows hindsight bias does in fact affect people of expertise as well, but also that it can influence testimonies and have serious impacts.

Another problem that arises is inaccuracy with predictions, which was explored in a study by Chelley-Steeley. Subjects were asked to estimate the probability for a certain event, value the claims they made, then once the event has occurred, they come back to collect their earnings. At this time they are asked to recall the original estimate of the value. The existence and level of hindsight bias was determined by comparing the actual estimate to the estimate made after they collected their money. Interestingly, they found that the higher the earnings from the event, the more likely people were to overestimate their original bet. This is likely a result of categorization and the spreading activation model. Categorization refers to how we organize stimuli in a meaningful manner based on shared features or examples. Spreading activation refers to the fact that when one word is activated, words that are associated with it are also slightly activated. Higher earnings are often correlated with success and correctness, which can bring about feelings of confidence. Thus, this categorization and activation resulted in greater hindsight bias in this study (Chelley-Steeley 2015). Here we see confidence is something that can play a role in the level of hindsight bias experienced, and as suggest before, this overconfidence can have downfalls.




I Knew It! (?)

Roese and Vohs close their argument by saying what we need to do is think about the other possible outcomes that could have happened in certain situations (2012). It is clear hindsight bias can occur in many situations and is accelerated by the fact that memory recall can be influenced by our perceptions and beliefs. We cannot just go right to thinking the story we have in our head is the right one, as most of the time we shape what we want to remember based on what we know. So, next time something happens and you think, “I knew it!” think again, because you most likely did not, in fact, know it.




Berlin, L. (2000). Hindsight Bias. American Journal of Roentgenology,175(3), 597-601. doi:175.3.1750597

Chelley-Steeley, P.L., Kluger, B. D., and Steeley, J.M. (2015). Earnings and hindsight bias: an experimental study. Economics Letters 134 130-132.

Roese, Neal J. “‘I Knew It All Along…Didn’t I?’ – Understanding Hindsight Bias.” Association for Psychological Science. N.p., 6 Sept. 2012. Web. 13 Apr. 2017.

Sanna, L.J., and Schwarz, N. (2006). Metacognitive Experiences and Human Judgment. Current Directions in Psychological Science 15(4) 172-176.

  1. tyao
    May 5th, 2017 at 22:56 | #1

    Thank you for your introduction to hindsight bias! It reminds me of the gorilla video we watched in class. I didn’t notice the curtain would change color, but when I knew it would, I watched the video again. I found that change really obvious. I remember that I said something like “there was no way I missed that obvious color change!” It was clearly inattentional blindness, but your introduction just made me realize I was experiencing hindsight bias as well. How could I have noticed that change without even acknowledging the existence of the curtain? How could I have missed something that obvious? It seems to me that hindsight bias makes me in the past a fool, and me right now an omnipotent, but that’s not the truth. Sometimes, we ARE very overconfident.

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