The Most Fascinating Cognitive Biases Ever Studied

The human brain is incredible and powerful, but it is not perfect. To process the overwhelming amount of information we come across each day, our brains turn to shortcuts to help us function efficiently. These mental shortcuts are known as cognitive biases. While they lead us to make decisions quickly, they can also result in inaccurate conclusions and irrational behavior. Many of these complex biases operate outside of our conscious awareness. Unbeknownst to us, they strongly influence how we view the world. Understanding these strange mental tendencies can help us become more thoughtful when making important decisions. Here are some of the most fascinating cognitive biases ever identified.

1. Confirmation Bias

Confirmation bias happens when we seek out information that supports already-existing beliefs. As we’re looking for this confirming date, we often dismiss or ignore evidence that contradicts our views. This bias affects everything, whether important political issues or trivial information. Because of this powerful bias, two people can look at the exact same information and walk away with completely different conclusions. Confirmation bias helps explain why changing someone’s mind is difficult, even when introducing valid new facts.

2. The Dunning-Kruger Effect

The Dunning-Kruger Effect occurs when people with little knowledge or skill overestimate their know-how or abilities. Studies have found that those who know the least about a subject tend to be the most confident. Meanwhile, the opposite can also be true. Experts frequently underestimate how much they know, presumably because they are aware of how complex the subject truly is. This bias has been observed in countless areas of life, from investing knowledge to mechanical ability. Ironically, the less someone understands, the easier it can be to believe they are an expert.

3. Anchoring Bias

Anchoring bias occurs when people grab too tightly onto the first piece of information they receive about a topic. That initial data, whether a number or a fact, becomes primary in the brain, influencing future decisions. Retailers can take advantage of this bias by displaying a high “original price” in big, bold numbers directly next to the sale price in smaller font. That first-seen higher number sticks in our heads, highlighting the discount. Even if the sale is not that great, the higher price makes the deal seem more impressive. This is why first impressions are so incredibly important.

4. The Halo Effect

The Halo Effect causes us to believe that a person who has one positive quality must possess many other good qualities as well. This is why attractive individuals are perceived as smarter or kinder. Their obvious good quality (attractiveness) leads others to assume they must have other excellent qualities too. The reverse can also occur, with a single negative trait shaping our entire perception of a person. Even when we believe we are judging people fairly, this bias influences us subtly. It affects hiring decisions, elections, and personal relationships. 

5. Availability Bias

People tend to judge how common or likely something is based on how easily examples pop to mind. For example, when they occur, aviation disasters are heavily featured in the news. Meanwhile, the thousands of planes that successfully take off and land each day are not front page news. This could lead people to rely too heavily on dramatic information, assuming plane crashes are far more likely to occur than they truly are.  This is known as availability bias. Because drama is easy to remember, horrible events often feel more common than they actually are.

6. Loss Aversion

Psychologists have discovered that people tend to dislike losses more than they like gains. The negative emotions resulting from losing twenty dollars usually feel worse than the positive emotions associated with finding twenty dollars feel good. This tendency can make people hold onto bad investments or stay in bad relationships simply because they do not want to experience a loss. Put another way, the fear of losing often has a stronger emotional impact than the possibility of winning.

7. The Bandwagon Effect

The Bandwagon Effect occurs when people take on beliefs just because others believe something, or when people adopt behaviors simply because others are doing the same. Because humans evolved to be highly social creatures, we naturally look to the crowd for guidance. Advertisers take advantage of this bias when marketing products. Fashion trends and viral social media challenges develop due to the Bandwagon Effect. Sometimes people trick themselves into believing they support an idea just because everyone else seems to. It turns out, the desire to fit in can be surprisingly powerful.

8. Hindsight Bias

Hindsight bias is defined as that feeling of “I knew it all along.” This bias distorts how we evaluate the past. After something happens, people frequently convince themselves that the outcome was foreseeable from the beginning.  For example, when we meet a new person, dozens of thoughts and feelings may come up for us in the moment. If our new friend turns out to be a serial killer, we might latch onto some of the more negative thoughts we had upon meeting them. Likewise, if the friend goes on to be the next Mother Teresa, we might only remember the positive thoughts that occurred to us during the meeting.

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