While modern life can intensify our anxiety, the building blocks for our struggle with anxiety can be found way back in the past with some of our earliest descendants. This is because there was only one goal for our early ancestors — survival — and we developed to survive above everything else. Being happy wasn’t a consideration to the evolutionary forces that shaped our early behaviours; the main aim was for us to survive long enough to mate and reproduce. Life beyond survival and reproduction didn’t matter.
However, the instincts and intellectual abilities that helped us to survive in the past — and can still serve us well now — have also created some present day negative consequences for us as individuals. We didn’t evolve to be happy, we evolved to survive. This has set us up for a number of difficulties. Why is this?
Well imagine what life was like for our very early descendants, the hominids. They were much slower than most other animals alive at the time, and in comparison they also had average sight and smell, and weren’t relatively big or strong. So in order to survive, our ancestors had to have other advantages.
These came in the form of an opposable thumb and flexible fingers — that could make tools and weapons — and also, in the brain, a growing cerebral cortex. The cortex played a very important role in the survival of hominids by remembering moments of pleasure and pain. It did this in order to figure out how to maximise future pleasure and avoid future pain. This motivated them to survive, while also keeping them safe.
he cortex produces thoughts that are tailored to the demands of its environment, and the environment of our early descendants was quite different to the modern developed world we now live in. Our ancestors lived in small bands or groups, it was rare for them to meet new people, and often dangerous when they did. They also faced starvation, parasites, illness, injury, and the hazards of childbirth; and there were no medications, painkillers, medical facilities, or police to help them.
This was where the human brain developed, and it was a hazardous and threatening habitat. In this type of dangerous environment our ancestors could make two possible types of mistake: thinking they had seen a lion behind the bushes when it was actually a rock, or thinking they had seen rock behind the bushes when it was actually a lion. The cost of the first mistake was needless anxiety, while the cost of the second mistake was death. So we evolved to make the first type of mistake multiple times in order to avoid making the second mistake even once.
There may have been some happy hominids who were carefree and not continually focused on looking out for danger, but it’s likely they weren’t the ones that reproduced our ancestors. Their genes wouldn’t have survived; they would have died before they had the chance to reproduce. So our ancestors remembered every bad thing that happened and spent much of their lives anticipating more trouble, and this is the mind we inherited from them.
Interaction of Survival Systems
Along with the cerebral cortex there are also a number of inbuilt survival systems that help to keep us safe from danger and motivated to survive, but the way these systems interact can sometimes cause us to feel anxious, stressed and unhappy.
The Negativity Bias
Research has discovered we developed what is called a ‘negativity bias’. So if you did ten good things today but made one mistake, it’s more likely when you go to bed tonight you’ll remember the one mistake — this is the negativity bias in practice. How and why does this happen?
Well there’s a part of the brain shaped like an almond, called the amygdala, designed to evaluate our environmental circumstances and decide whether something is a threat or not. The amygdala reacts far more rapidly and thoroughly to negative than positive stimuli. As a result, the negative tends to contaminate the positive far more easily than the positive contaminates the negative.
This is why we react more strongly to threats than positive events, why trust is easy to lose but difficult to gain, why negative political campaigns tend to dominate the media, and why we spend more time on social media criticising what we don’t like or agree with rather than promoting what we love. Negativity gets people’s attention more quickly and easily, and takes precedence over positive information.
The negativity bias developed in very harsh conditions, but continues in today’s relatively safe environments. So we can react to relatively safe and benign conditions, such as talking to a stranger, going on a date, or making a speech, as though they are life or death situations, and very often we expect the worst.
The Emergency Arousal System
The negativity bias also interacts with our emergency arousal system — the fight, flight or freeze response — which can be triggered by the negative thoughts we have. When triggered, the amygdala, from its central position in the brain, sends out instructions to energise the sympathetic nervous system, increasing the levels of hormones such as adrenaline and cortisol in bloodstream.
This results in a number of changes in the body, including: elevated heart rate, more rapid breathing, dilated pupils, blood flow diverted away from the digestive tract to the limbs, and tensed muscles. The body is now primed for action. When this happens you may feel like your heart is pounding, your body is trembling, and your stomach and bowels are distressed.
When this reaction is needed, such as in a life saving emergency, or in a very challenging environment, it’s extremely helpful, but if the arousal system overreacts, it can set off a fully blown panic attack when no logical reason for fear exists. Our bodies evolved to react like this occasionally (like when we see a dangerous animal or need to run away from a group of enemies), but we don’t cope very well when it’s activated all day long, over weeks, months, or years. When it is, it sets us up for many anxiety related ailments, both physical and mental.
Indeed, long-term elevated cortisol levels can: lower immune function and bone density; elevate blood pressure, cholesterol, and body weight; increase the risk of heart disease, depression, and mental illness; and interfere with learning and memory. Changing the way we think about our stress response can minimise these negative effects and even benefit our health. However, the stress response didn’t evolve to be continually activated for long periods of time, but only when needed for survival, or to help us in a challenging situation.
Seeking Pleasure and Avoiding Pain
As mentioned earlier, we evolved to pursue pleasure and avoid pain. This motivates us to do things that perpetuate our DNA, normally through pleasurable experiences such as sex, eating, sleeping, and finding a safe home. As a result we can get hooked on constantly seeking these things, and when we don’t have the perfect conditions that allow us to experience them, or fear we could lose them, it makes us feel distressed. So we’re not only impacted by immediate threats to our survival, but also the fear we won’t get what we evolved to seek out, or lose what we have.
So these three survival systems do an excellent job of keeping us alive, while also pushing us to experience pleasure, but their interactions also prime us for anxiety.
On top of these three hardwired survival systems, we have also discovered learning changes the brain, through what neurologists call experience-dependent neuroplasticity. Scientists used to think the brain reached maturity around the age of 25 years and then deteriorated. Now we know it’s much more like a muscle, and while it ultimately weakens over our lifespan, when we use specific neural pathways in our brain, they become stronger, and if we don’t, they become weaker.
The principle of neuroplasticity is relatively simple: information travels throughout the brain via electrical impulses that move along nerve cells called neurons. In order for an impulse to travel from one neuron to another, it has to pass through synapses separated by an empty space called the synaptic cleft. Whenever we have a thought, a synapse fires a chemical across the cleft to another synapse, building a bridge over which the electric signal can cross, carrying the information along its charge. Every time this chemical is fired, the synapses grow closer together in order to decrease the distance the electrical impulse has to cross.
This is the brain rewiring its own circuitry, physically changing itself, to make it easier and more likely the most used synapses will share the chemical link and fire together. This makes it easier for the information to be passed on. So the repetition of signals travelling down the same pathways, through repeated behaviour and learning, reshapes the brain. This is why, in 1949, neuroscientist Carla Shatz coined the term ‘Neurons that fire together, wire together’. As a result, negative (and positive) thought patterns can deepen and become more habitual, like a riverbed that deepens over time.
With all of these evolutionary hardwired systems operating to help us to survive, it’s no wonder we so often find life difficult in the developed world. However, there are interventions that were developed in response to this complex evolutionary predicament. Mindfulness interventions are particularly effective and far-reaching in their effect on mental wellbeing because they address two challenges simultaneously:
Firstly, they can provide insight into the patterns of the mind that create anxiety and suffering, radically changing our views of ourselves and others.
Secondly, they can retrain the brain not to automatically respond using these instinctual patterns.
Now we have some understanding of why anxiety developed, how it has played a vital role in helping us survive, and why we can find it so troublesome. Next we’re going to take a closer look at the processes that take place in the brain when we experience anxiety. Understanding where the anxiety response starts is key to effectively managing our troublesome brains.
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