One of my new favourite TV shows is BBC4’s It’s Only A Theory, where experts chat about their (often surprising) theories. Presenters Andy Hamilton and Reginald D Hunter, along with a weekly guest, review the theory with a good mix of comedy and honest discussion. It’s a bit like Dave Gorman’s Genius, but with genuine theories, and a bit less silliness. Watching it last night got me thinking about a theory I’d take to the panel (if I were an expert in something – which I’m not)…

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?