Don't walk, boogie

This post is for Louisa Wells.

This post is for Louisa Wells.

Here is something amazing that your brain does. When you walk across a room, whistling dixie and daydreaming about the upcoming weekend, your brain is constantly interpreting the information your body sends, and sending back signals about what is going to happen next. And what is going to happen next is your foot is going to land on the floor and you are going to move forward.

This might seem so banal as to be absurd to spend anytime thinking about. But let’s think a little. I believe Wittgenstein said something along the lines of: ‘it is the things that are under your nose that are the most profound, yet the hardest to get a grip on.’

The feel of your foot landing on the floor when you walk is not the feel of a robot hobbling along – you do not get the signal ‘foot on floor, other foot behind, foot on floor, other foot behind, foot on floor, wall to the left!, other foot behind, wall to the left!, wall to the left!…’ That would drive you nuts.

What you get is a smooth flowing feeling with everything integrated together. Think about that for a minute. What a great thing walking is! But don’t think too much, otherwise you’ll walk self-consciously, and you won’t quite feel yourself.

That last phrase is interesting; ‘you won’t quite feel yourself.’ It gives us a clue to our natural everyday sense of self, the one that is right under our noses all the time and without which we’d, well, not be ourselves. How does the brain create this sense of self?

You take a trip on a ship. You throw-up for a couple of hours, then you feel kind of okay. You ‘feel yourself again’ (but a bit rough). Or, you spend a week at sea then walk on land: you feel a stomach-churning shaking in your legs, and you don’t feel yourself for quite a while. What’s happening here is the clue to understanding how the brain creates that sense of self that is under our noses everyday.

In our brains – in the unconscious ‘emotional’ parts of them we share with other animals – there are neurons that transmit dopamine. These neurons form systems that predict what is going to happen around you. There are millions and millions of them, and they can process millions of bits of data at the same time. When you have an experience, they record what happens, and then when you have similar experiences in the future, they predict what will happen then, based on what's happened already. Even experiences as mundane as walking across a room.

These systems of dopamine neurons feed into the rest of the brain – the conscious parts concerned with decision-making, the unconscious parts concerned with multi-sensory processing, the whole damn caboodle. When your foot steps normally on the floor dopamine flows at a certain level into the rest of the brain as patterns are recognised and predicted (‘if a step forward is taken, the floor will be there, oh good the floor is there’). Of course you are not conscious of any of these signals (that is what would drive you nuts). What you are conscious of (I want to say ‘dimly conscious of’?), is that smooth feeling of integrated poise.

When you get sea-sick, or land-sick, what is happening is that your unconscious brain creates a change in the dopamine levels fed out into the rest of your brain. This alerts you to patterns that weren’t predicted (‘if I put my foot forward the floor will be there, I put my foot forward, woh - the floor is not there!). The consequent alert takes the form of feeling queasy.

Isn’t that amazing, all that computation and prediction just to walk across a room! What an absolute masterpiece of molecular engineering you are! It’s the simple things in life that give pleasure…

One final thought. I think the Pentagon should weaponise dopamine prediction systems. They should invent a bomb that affects soldiers’ ability to do everyday things like walk around with that smooth feeling of poise. The enemy would just stay at home and watch telly – ‘don’t quite feel myself today… a bit out of kilter – can’t quite put my finger on it, just feel a bit weird.’ On the scale of harms done by weaponry this has to be on ‘the not too bad’ side.