The Brain is Not a Computer

I actually think the brain is a computer, if you define “computer” quite broadly as an information processing machine. And if you define “information”, “processing” and “machine” quite broadly too. What I’m actually saying it that the metaphor of the brain being like a desktop computer isn’t a very good one.

It is a useful metaphor to understand the difference between the brain and the mind (brain being the “hardware” and mind being the “software”), but that’s as far as it’ll take you. Beyond this, in any way you’d care to compare them, the brain and a computer are different.

Computers are mostly serial processors, they do one thing at a time, in a pre-defined sequence. Parallel processing is becoming more and more common, but a quad-core processor is hardly comparable to the 100’000 plus processing units of the brian – neurons.

Computer memory is designed to store data accurately, for a long time. There are checksums and recovery processes built in to computers to ensure that the data stays the same as it’s moved between hard disks, RAM and across networks. Human memory is nothing like this. Information in our brians degrades over time.  It is recalled, reviewed and rebuilt in many different ways, all the time. When we fist ‘make’ a memory, it’s already inaccurate. We don’t remember everything we see or hear, only the bits we find interesting at the time, or more accurately, the bits our brains tell us are probably the most interesting. When we recall memories the gaps are smoothed over by intuition and guesswork.

Computers break. They break a lot. For no apparent reason a computer can just stop working. This doesn’t happen to our brains,  if parts of our brain has problems other parts can step in. Studies on amputees have shown that ‘unused’ parts of the motor cortex can be reused by neighbouring parts. This can give peculiar sensations like feeling a feather on a missing hand when it’s brushed against the cheek.

There’s three reasons, but there’s countless more. In nearly every way brains are good at the things that computers are bad at, and vice-versa. I’m not saying that computers can’t be programmed to act like brains, artificial neural network models are more common than you might think. But computers are also used to model, engine parts, bridges, traffic flow, economic strategies, wars and a ton of other things, none of which we compare to being ‘like’ computers.

So that’s my theory. ACCEPT or REJECT?

]]> http://www.craig-russell.co.uk/its-only-my-theory/feed/ 0 http://www.craig-russell.co.uk/gravity-goblins-and-confirmation-bias/ http://www.craig-russell.co.uk/gravity-goblins-and-confirmation-bias/#comments Fri, 02 Oct 2009 15:39:52 +0000 Craig http://www.craig-russell.co.uk/?p=305 I’ve got a theory about gravity, not just a theory, an explanation for how gravity works. I can tell you, dear reader, exactly why bodies of mass are drawn together. My theory is clear, simple and above all correct. I know this because I have proven it. The proof is all around, as clear as sky. Allow me to explain…

My theory of gravity is simple, all objects on this earth have invisible pieces of string attached to them, upon the oppisite end of which little invisible goblins hang off. That’s correct – invisible goblins.

What do you mean you don’t believe me? Fine, I’ll prove it to you…

Pick up a pencil (or any other object you have to hand) hold it at arms length over the floor and prepare to release it (being mindful of any children or animals below). Now if my theory is correct, when you release the pencil, the Gravity Goblin (as I have christened them) will pull upon the invisible string, drawing the pencil towards the floor.

Ready…?

Release…!

Theory proven. I thank you.

Obviously, this is bollocks. But I tell it to illustrate a key part of the scientific process – falsification. Falsification allows us to differentiate between Gravity Goblins and Isaac Newton. Any monkey can “prove” a hypothesis (I’m using the more scientifically appropriate term now), finding evidence in support of a hypothesis is easy. Just pick any phenomena you fancy and make up some bullshit to connect cause and effect.

Soap bubbles in the washing up bowl? – Microscopic scuba elves.

Crystal Healing? – Energy flow and focusing and karma and that…

Homeopathic Remedies? – Diluted sub-molecular chemical memory or something…

The massive diversity of life on Earth and the subtle interactions and behaviours therein? – God.

For a hypothesis to be scientifically tested (and hence logically robust) you’ve got to attempt to prove it wrong. You’ve got to be prepared to say “if my hypothesis is correct, I can hit it with the sledgehammer of reason and it won’t crack”. Suggest a way to break it and invite others to try, if it stands up, well done, you’ve got yourself a robust theory.

Despite what you may (or may not) have thought, this kind of thinking doesn’t come naturally to our human brains. We have a habit of favouring evidence that supports our beliefs while giving less weight to the opposing evidence. Psychologists call this effect ‘confirmation bias’.  Understanding our natural tendency towards confirmation bias makes it all the more clearer why a scientific, rational approach to exploring ideas is so powerful.

Without knowing how to properly test our ideas, how to prove them wrong, we’d never be able to develop our ideas, to differentiate fact from superstition. Without falsification, we could all be believing in Gravity Goblins.

I love ants, and bees, and social insects in general. The emergent power of the collective is facinating.

I’m reading Steven Johnson’s Emergence again at the moment, cracking book.

These incredible images have been captured by a brain acanning technique called DTI (Diffusion Tensor Imaging). Essentially DTI uses an MRI scan to track the flow of water in nerve cells, these images here show the white matter connecting the grey matter in a schitzophrenic’s brain.

Link to Paper

Also, the paper is hosted on Scribd, a site which allows free access academic papers. I’m going to have to check this one out…

Martin Pyka has produced this awesome model of the brain, with all the different regions labeled up. His site’s written in German, but the model itself is printed with the English (and Latin) names for the brain regions.

I think I’ll be adding this one to the collection tonight.