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  • Bitesize Behaviour Host

Series 1, Episode 2: Evolution

We start our journey on the Bitesize Behaviour Podcast by looking at how we make decisions and the importance of behaviour on everything we do.

Now in order to give us the right foundations, we need to go right back to the beginning and go on a quick journey of evolution, which starts 3.5m years ago.

This is the furthest back that we can trace us as a species - when we first climbed out of the trees and stopped moving around on all fours, to become bipedal - or walking on two legs.

Our brains at this time were obviously still very primitive, but over the next 3 million years they developed considerably - to the point where, half a million years ago we had developed enough brain power to figure out the best way to hunt using basic tools that we’d crafted in order to make the gathering of food a more efficient process. Now, if we advance another 350,000 years, we reach the birth of modern man - the species we recognise in ourselves today.

Fast forward to today and here we can reflect on the journey we’ve taken over the last 3.5m years and pat ourselves on the back for an evolutionary job well done. We’ve mastered flight, domesticated fire, invented the wheel... you know the list right - it’s long and very self congratulatory.

However, there are things that haven’t developed so quickly and some things that have never changed since day one 3.5m years ago.


An example of something that hasn’t developed as quickly as we may think - is our ability to read and write - especially given that writing has been around for thousands of years. In the UK specifically - and data on this is available for most countries of the world - the average reading age is around 9 years old and the average maths or basic numeracy age is 11 years old.

And that can create problems for us, for example, when we need to read information to make a decision, and especially when information we’re reading is complex, or includes jargon, or specific words that have specific meanings. We can run into problems quite quickly.


The second element that I want to look at is much more powerful, because this is programmed deep into our DNA. It’s an evolutionary trait that has never left us (thankfully) and that behavioural trait is FEAR.

Now, fear, worry, anxiety, stress… all have an impact on how we move through the world we live in, and therefore how we make decisions. To understand this a bit more, we need to take a quick and really simplified look at the brain in relation to fear.

To make this understandable, and get to the point, think of the brain has having only three main parts - three simple sections. Section 1 is the neocortex and it’s the biggest part of the brain. It is responsible for things like imagination and planning. In the centre of the brain is section 2 - the mammalian brain - the part that is responsible for our emotions and habits. Finally section 3, at the base of the brain is the reptilian brain - or the brain stem - which has the incredibly important job of keeping us alive. It deals with all of the automatic functions we need to stay alive - like breathing and your heart-rate.

That’s the three main parts, but there are two other important parts of the brain which are tiny, but crucial in understanding how the brain processes fear - and they are the amygdala and the hypothalamus.

Now, when the brain senses fear - the specific place we sense this is the amygdala. The amygdala then sends a signal to the hypothalamus telling it that danger is imminent and to take action. The hypothalamus then triggers a series of biological processes that are so fine tuned, we’ve survived 3.5m years to tell the tale. We know this process as fight or flight, which I’m sure you’ve heard of.

If you want to learn more about this process, which is absolutely fascinating by the way, just go online and search for your sympathetic nervous system, and you’ll learn just how amazing your brain is at keeping you alive.

But, the reason for mentioning all of this, is this.

When we sense fear, and the amygdala and hypothalamus combine to keep us alive, something else important happens at the same time. In preparing us for fight or flight, the prefrontal cortex, which is the part of the brain responsible for making decisions, gets temporarily turned off.

So what this means is that under conditions of fear, stress, worry, anxiety, panic, we aren’t biologically wired to make clear headed, efficient decisions. This is really important to remember - especially when you consider that some decisions, especially decisions that involve things like money, can naturally bring about stress, worry, or panic.

What this means in reality is that we really should try and avoid making decisions that could have a long term impact on our wellbeing if we are in an anxious or fearful state of mind.


If we don’t deal with complexity very well, and our biology means that if we’re anxious, stressed, or fearful our decision making is clouded, how on earth do we end up making decisions in the first place. How do we deal with complexity, and how do we get to a place where we can at least start to make decisions? The answer to this is in the next article in the Bitesize Behaviour Podcast companion.