What is... psychology series

What Is… a Cognitive Bias

list of common cognitive biases

In this series, I dig a little deeper into the meaning of psychology-related terms.  This week’s term is cognitive bias.

Do you think you’re biased?  Well, your brain certainly is.  A cognitive biases is a type of shortcut your brain takes to make tasks easier and more automatic.  Sometimes that’s helpful, but often it’s not, especially when we’re unaware of it.

Here are some examples.

Ambiguity effect: we’re naturally inclined to go for the “sure thing” rather than something with an uncertain outcome; this is true even when the result would be better if the uncertain outcome occurred

Anthropomorphism: human characteristics are attributed to non-human objects, e.g. my belief that my guinea pigs love me

Belief bias: the strength of a logical argument is evaluated based on the subjective believability of the conclusion rather than on the strength of the arguments that led to the conclusion

Ben Franklin effect: if you’ve previously done someone a favour, you’re more likely to do them another favour than if it was them who had originally done a favour for you

Bias blind spot: we tend to believe that we are less biased than other people are

Confirmation bias: we tend to both seek out and focus on information that confirms what we already believe, and ignore information that goes against our beliefs

Curse of knowledge: this is the assumption that other people have the same level of background knowledge as you do; I tend to get caught up in this, so I ‘ve never been very good with nursing students because I always assume they should have more knowledge than they actually do

Framing effect: receiving the same information is evaluated differently depending on how it’s framed

Gambler’s fallacy: believing that because you’ve had half an hour of losing at a particular slot machine, the machine is due to pay out imminently

Hindsight bias: an outcome seems like it should have been obviously predictable after it’s already happened

Hyperbolic discounting: the preference for a smaller short-term gain over a larger but delayed gain

Negativity bias: we’re more likely to notice and remember things that are negative compared to things that are positive

Observer-expectancy effect: expecting a certain outcome causes the observer to unconsciously do things to influence the outcome; clinical research trials are often designed to be double-blinded to account for this

Post-purchase rationalization: even if you spent far too much money on something, you’ll likely try to convince yourself afterwards that it was totally worth it

Reactive devaluation: if someone you don’t like makes a suggestion, you’ll tend to automatically assume it’s a bad suggestion

Rhyme as reason effect: this seems utterly bizarre, but Wikipedia gives this example from O.J. Simpson’s trial: “If the gloves don’t fit, then you must acquit.”

Sunk cost fallacy: the tendency to think that you should stick with something because you’ve already put a lot of time/effort/money in

Unit bias: even if you’re only hungry enough to need a small plate of food, if given a large plate, you’ll judge that full plate as being the appropriate amount


There are many, many more examples of cognitive biases.  Some of them have a greater degree of voluntariness, such as the ostrich effect (i.e. sticking one’s head in the sand to ignore something bad happening). Others we likely wouldn’t realize if they weren’t pointed out to us.  Regardless, the ways that we perceive the world around us are often not an objectively accurate representation.

Source: Wikipedia: List of cognitive biases


Psychology resources: What Is insights into psychology series and psychological tests

You can find the rest of the what is… series here, and a collection of psychological tests here.

25 thoughts on “What Is… a Cognitive Bias”

  1. Wow, I could relate to so many of these!! Like, check, check, check, check, check. What a fascinating list! Oh, but I’m sure the guinea pigs love you to death!!

  2. Wow! I’ve heard of some of these but certainly didn’t realise there are so many typical patterns influencing thought, judgement and action. Great post x

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