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  • Bitesize Behaviour Host

Series 2, Episode 2: Confirmation Bias

We kick off looking at a behaviour that has been described by some psychologists as the mother of all behavioural biases, and that is confirmation bias.

So what is confirmation bias? Well to explain that, let me give you an example.

Say you want to go on holiday and you’re thinking of a place that you’d like to visit, let’s call it Bluestream and your friends tell you that the crime rates in Bluestream are really high and it’s a dangerous place to visit. They suggest you should check it out for yourself online. You fire up the laptop, open google, and probably type in something like “crime rates in Bluestream”, or you might type in “where should I avoid going in Bluestream”. The problem with searching like this, is that the information you will see, will probably only confirm the comments your friend made, that Bluestream isn’t the best place to visit and you will come to the conclusion that your friend was right and now you will likely hold the same opinion and belief.

But in essence, what you’re actually doing is looking for evidence that only supports one side of the story. You aren’t looking at all available information - in a positive and negative way. In the instant information world we live in and where you can pretty much search for any opinion or view online, it’s important that you don’t only search to confirm what you’ve already have been told, or what you already believe.

This is confirmation bias in action. And to give it its text book description, It’s a behavioural bias where we look for information or evidence that only supports our existing beliefs or opinions, whilst at the same time, ignoring evidence that could prove we’re wrong.

Now as humans making decisions all the time. I read somewhere that we make around 35,000 decisions a day (although without concrete evidence to support that, please take it with a pinch of salt, else I am creating confirmation bias right here). As we make decisions all the time, confirmation bias is one of those behavioural biases that escapes no-one. Even when you know it exists, it’s really, really, really difficult to stop it creeping into our lives.


This is especially true when you are asked to make a decision on something that is very personal to you, or carries a great deal of emotional attachment. To give you an example, we can look at something that has an emotional element attached to it - global warming. Now, If you believe that global warming is a genuine threat to the future of our planet and therefore our very existence, then searching for evidence that just proves that point, won’t give you a rounded, all-perspectives view on the subject. Basically, unless you understand both sides of the argument, the why’s and the why-nots, your view on the subject will remain biased and is likely to be topped up with unhealthy doses of confirmation bias every time you search for new evidence to support your existing beliefs.

You need to try and leave your emotions at the door, so to speak, and only focus on hard facts… proof, genuine un-biased evidence that provides the correct answer, irrespective of whether that aligns to your beliefs or not.


I’m not saying that’s easy by the way especially with all the mis-information out there which is so easy to find. There needs to be a bit of effort on our part to get to the truth.

Now confirmation bias can also reveal itself in quite scary ways. There is a great piece of research carried out in 2007 looking at confirmation bias amongst doctors. Basically, a bunch of doctors were given a case study and asked to diagnose a patient with a medical problem. Once the diagnosis was in, many of them proceeded to only asked questions and search for evidence that supported their diagnosis, whilst at exactly the same time, ignoring the evidence that would prove their diagnosis was wrong. 20 out of 100 doctors ended up mis-diagnosing the patient and therefore giving them the wrong treatment plan. This is confirmation bias in practice, as well as some other behavioural biases that we’ll talk about in later episodes.

So, for this behaviour, as a good first step, we have to try our hardest to see things from every angle. From all perspectives. But most of all, please, please don’t spend all your time and effort looking for information that only supports what you already believe. If you do this, you could end up making a decision that really isn’t in your best interest.

If you want to learn a proper technique to make better decisions and push confirmation bias to the sidelines, there is a great technique you can adopt, taken from a book written in 1985 by Edward De Bono. It’s a great book called Six Thinking Hats.

Six Thinking Hats details a straightforward technique that helps you look at problems from different perspectives, but, importantly, one at a time… which helps avoid confusion and overloading your brain.


That is the bitesize behaviour of confirmation bias. In the next episode, we’ll be looking at the behavioural bias that marketing companies use a lot, to make us buy more of their stuff - we’ll be looking at framing bias.