Your amygdala doesn't care whether you get embarrassed or not.

If you are going to learn to handle anxiety, this is crucial to understand: when the amygdala is centre stage, excitedly setting off alarms like this to save our skins, it is so powerful that it can actually shut down our higher intelligence completely.

It is as if it has a simple on|off button that it can use to deactivate the thinking part of our brains. When our bodies are in a state of high emotional arousal (whether we are angry, terrified or head over heels in love), we are not thinking straight. High emotional arousal makes us temporarily stupid. Or, to put it more politely, it reduces our options to a simple choice to force us to take action.

It has to be this way.

For example, if from down the street you see a motorbike up on the pavement, accelerating towards you, you don’t want your thinking brain weighing up the odds and wondering, “Surely he knows he shouldn’t be on the pavement? Maybe it’s a film stunt? In that case, where are the cameras? Is that a Harley-Davidson he’s riding? Hmmm … actually he is going very fast. And he is driving straight at me! I wonder if I should just step out of the way in case he hasn’t seen me … ?”

By that time, you might well be dead.

So, in such life-or-death circumstances, we don’t want a highly intelligent system that can carry out reasoned analysis. We want an excitable (and therefore stupid) system that can terrify us and make us dodge the bike and run for it before we even know what we are doing!

So sometimes panic is the right response. In other circumstances, however, the ‘threat’ might tum out to be harmless and, if you have already legged it, you might well feel a prize fool.

But your amygdala doesn’t care whether you get embarrassed or not. It knows that you can get embarrassed a hundred times and it won’t kill you; but fail to act on a genuine life-or-death threat just once, and you are likely to end up never needing this wonderful survival mechanism again.

Strong emotions focus and lock our attention ... everything is simplified to a black-or-white choice...

The ‘thinking’ part of our brains (the neocortex) is relatively new in evolutionary terms. Before our brains developed into the awesome organs they are now, enabling us to plan, imagine, analyse things and make judgements, we relied for our survival on our more primitive ‘mammalian’ brain.

The mammalian brain, a set of structures which lie underneath the neocortex, is often termed the ‘emotional brain’, because it is concerned with instinctive responses involving emotions – most notably the fight-or-flight (anger or fear) response. All instinctive behaviour concerns survival: feeding, mating, fighting or fleeing. And our instincts induce emotions that require us to take action (ideally to carry out the instinctive behaviour so as to lower the arousal again). All emotional needs arise out of this fundamental survival programme.

When the neocortex developed, we had rational intelligence at our disposal, as well as emotional intelligence, and, in the ordinary everyday, the two intelligences work together in partnership, with the rational brain adding subtlety and perspective to the raw feelings of the emotional brain, and the emotional brain tempering the rational brain’s cool clinical judgements. But emotions can often overpower the rational brain, as we shall see.

The emotional brain contains a very small and powerful structure known as the amygdala – so called because it is almond-shaped and amygdala in ancient Greek means almond.

In effect, the amygdala acts as the body’s alarm system. It has access to our store of emotional memories and learned responses and its job is to be alert to any possible danger to us by matching new events to patterns in its store and, from that, judging whether we might be at risk.

For instance, suppose we are walking alone down a dark street late at night and there is a sudden unexpected crunching sound or a quick movement. Our attention is drawn to it instantly and, in less than a split second, our amygdala decides whether the sound or movement could signify danger.

It pattern matches the sound to the crunch of footsteps. It pattern matches the movement to that of a person darting out of an alleyway. Making its best guess, on the basis of what it knows from its memory stores that the sound or movement could signify, the amygdala takes the worst-case scenario and sets off the alarm by making you feel anxiety.

In effect, it concludes, “We are under threat! Or, at least, we might be! So we had better be ready to turn and fight or else run for it.”

Because it needs to make an instant decision to get us out of any potential danger as quickly as possible, the amygdala’s pattern matching is very crude. It is black and white – a situation is either safe or it isn’t. Therefore, it doesn’t have the sophistication of the thinking brain, which can introduce some shades of grey to the situation and might conclude that, yes, the crunch is definitely footsteps but the owner of the feet, far from being a psychopathic killer, is probably only a neighbour from down the street.

And the sense of movement from the alleyway is not a shadowy alien figure with ill intent but merely a black bin bag blowing in the breeze.

But, at this point, the thinking brain hasn’t yet had a look in.

When the amygdala decides that we might be under threat, it takes the steps required (by sending chemical signals) to set the fight-or-flight response in motion without seeking any by your leave from the neocortex.

In fact, this has all already happened by the time the neocortex gets to know what is going on half a second later. Our heart is already pounding, our legs shaking and our breathing coming short and quick by the time we recognise Bob or Nancy from two doors down or identify the bin bag.

We quickly calm down then, of course, and become reasonable people again, instead of gibbering wrecks.

Taking appropriate action of some kind both relieves the stress and helps us avoid developing anxiety.

Imagine for a moment that we are our long-ago ancestors, still living in the wild. Our very survival depends on our being ready to react instantly, if a wild boar thunders out of the undergrowth or members of a hostile tribe come over the hill towards us. As soon as we sense a threat, a cascade of bodily events is triggered to help us cope. Almost instantly, the following happens:

Our muscles tense ready for action. Our blood pressure goes up, to increase the circulation to our muscles and heart, which beats faster, to cope with the expected increased demands on it. We breathe faster, to speed up the time oxygen takes to get into our blood, and that makes our anxiety chests hurt and our bodies tremble. To divert as much blood as possible to our limbs to aid action, our digestion is interrupted, making our saliva dry up, and our kidney, intestine and bladder functions stop, causing the muscles at the opening of the anus and bladder to start to relax.

We sweat, to try to cool ourselves. Our bodies are flooded with ‘stress’ hormones that enable all these responses to happen and, as a result, we immediately flee the wild boar or fight the unwelcome tribesmen.

Once the threat is over, if we are still alive to tell the tale that is, our hearts slowly pound less, the shaking gradually stops and the sick feeling passes, as our blood circulation returns to normal and digestion and the other regulatory functions start up again. The stress hormones that were swarming through our body have been burned up during the action we took or else are neutralised as our body maintenance gets back to usual business.

This excellent system has served us well for millions of years. But it was designed to deal with circumstances in which we could take action. The stresses we face today are less often of the life-threatening kind. More usually, we find ourselves in circumstances where we feel psychologically threatened (the boss is critical of our work; someone else is getting our promotion; we’re being bullied at college; a neighbour is continually picking arguments).

Or we feel unsafe (we may fear walking the streets at night or meeting gangs of teenagers; the news is full of gloomy predictions about wars and global warming and deadly diseases).

Or we feel ‘cornered’ – but not by a wild beast that we can flee – we are stuck in a traffic jam; work deadlines are unrealistic; the phone keeps ringing.

The very primitive, early-developed part of our brain (which gives the directions that set our fight-or-flight response in motion) is not able to distinguish between events like those above which it perceives as threatening and those that actually are life threatening. Even worse, it cannot distinguish between real or imagined life-threatening events either. (“I’ll die if I have to get up on that stage and speak!”) Indeed, when the fight-or-flight mechanism first evolved, we didn’t have a ‘thinking’ brain and there was no such thing as imagination. So now, if we imagine ourselves experiencing disaster vividly enough, we can still easily trigger off the fight-or-flight response.

But, when we are being criticised by the boss, sitting stewing in a traffic jam or imagining being trapped in a lift, there is nowhere to run to and no one to fight. And, although the physiological arousal that is switched on when we get stressed in such ways is mopped up quite quickly, an expectation – that something will or should happen – also gets switched on in the brain, and stays switched on, taking up our attention and energy.

This is a cumulative process and, with each additional stress, not only does more and more arousal occur but more and more expectation patterns stay switched on in our brains.

Eventually this puts too much stress on us physically and it is at this point that one person might start to develop anxiety headaches or angina; another will turn to drink; and you may develop an anxiety disorder. Whatever the reaction, it is the body’s message that it has been pushed too far.

Of course, stressful events will always happen. Some will drop out of the blue to scupper our plans, however well we may think we have prepared for every eventuality. At some point, someone we love will die. Companies go bust. Fires, floods and other natural disasters are all out of our control.

But what is within our control is learning how to deal with stress when it arises. By taking appropriate action of some kind, we can dissipate the stress hormones – this both relieves the stress and helps us to avoid developing anxiety.

So, while we can’t prevent a lot of the stressful events we face in life, we can develop psychological robustness.