Understanding the human CPU
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Neuroscientist, technologist and TV presenter David Eagleman discusses why the ‘liveware’ of the human brain is like a computer, only more so.
“As engineers and technologists, essentially everything we think about is either hardware or software,” says David Eagleman. But as a neuroscientist, as well as a technologist developing products that interface between the human and electronic machine, Eagleman needs more flexibility in the vocabulary that describes what’s going on.
In his new book, ‘Livewired’, Eagleman coins the word ‘liveware’, “because that to me is what captures what the brain is doing. It’s a different kind of system to what we know how to build.” And when we say the brain is different from systems such as factories, computers or cars, “what we mean is the kind of factories, computers or cars that we build currently”.
When you construct a car, says the American TV presenter, “what you do is basically establish a chassis and run some software on top of that. But what happens in biology is that you have adaptive systems that change themselves on-the-fly relative to their experience of the world. That’s what happens with the brain. It’s an enormous forest of 86 billion neurons that are plugging and unplugging and seeking and finding new places. This forest is in constant motion.” In the time it took you to read this paragraph, your brain has changed. The reason you will hopefully remember the content of this article is because while reading it a change has occurred in the structure of your brain.
One of the themes of ‘Livewired’ is Eagleman’s focus on how the STEM community can aspire to build machinery that operates in a comparable manner. “To do this we would have to leave behind the idea that we are making software or hardware, and we’d have to build liveware.” To demonstrate the point, Eagleman tells two stories contrasting the fortunes of the Mars Rover Spirit that got trapped in the Martian sands and “essentially died”, and that of the wolf that got its leg caught in a trap and chewed its own leg off to free itself. “It then walked away on only three legs. Obviously, the wolf brain didn’t evolve to deal with a body with three legs. But it can figure it out.” Meanwhile Spirit has sent its last message to Earth.
The reason the wolf could adapt while the Mars Rover could not is “because brains aren’t pre-programmed to perform in a particular way. They’re pre-programmed to figure out how to interact with the world in a way that maximises their ability to thrive. Imagine if you could just drop any engine onto any car chassis and it could work out how to evolve. Imagine a piece of commercial real estate that notices that there’s a lot of traffic to the rest rooms, and so it just ‘grows’ more urinals. This sounds crazy to us right now. But this is exactly what the brain does – and we can take a lot of inspiration from this.”
‘Livewired: The Inside Story of the Ever-changing Brain’
Unlike the machines humans currently manufacture, the brain is so much more than a combination of hardware and software. In fact, says David Eagleman in his new book ‘Livewired’, we need a new word to describe what’s going on in the immense forest of neurons that makes up the human brain: ‘liveware’.
It is through understanding the adaptive potential of the brain that we can emulate its workings to produce better, more intelligent machines in the future. The magic of the brain, says Eagleman, is not to be found in the parts it’s made up of, but in the way those parts endlessly re-weave themselves into an electric, living fabric.
Packed with a mixture of illustrative anecdotes, ‘Livewired’ also has the scientific rigour that comes from decades as a leading researcher – including new discoveries from Eagleman’s own laboratory – in the field of brain plasticity.
To illustrate how human senses interact and evolve, Eagleman has proposed a plug-and-play principle that in its simplest form works just like the early-years education toy formerly known as Mr Potato Head, but subsequent to its gender-neutral makeover is now just Potato Head. But, he says, you could also look at it in the way the peripheral connectivity of our desktop computers works. If you cast your mind back a few decades ago, says Eagleman, printing anything was the bane of all office life. Getting a printer to work bordered on impossible as you tracked down and installed drivers before giving up. Now you can just plug in (or connect wirelessly) virtually any device and the computer will “work out what’s on the other end of the USB and it will just happen. That’s what’s happening with the brain. Instead of the brain having to change, it can work out and adapt to anything that’s plugged into it – eyes, nose, fingertips or whatever – and treats them as plug-and-play peripherals in this analogy.”
Spread this across the animal kingdom and you can find “all kinds of different inputs: infrared, electro-reception, magneto-reception and so on. These are typical things that different species of animals have. But the point is that their brains are the same as ours. All that’s happening is that the peripheral detectors are translating whatever it is they’re translating – photons, air compression waves, temperature or pressure – into spikes of electricity that travel along neurons. Which means that the brain is a general-purpose computing device that’s saying: here’s how I can use that data to do something meaningful.”
For the reader who thinks that ‘Livewired’ is just another brain book to be passed over because these days books about the brain tend to rehash the same approaches, it’s time to think again. “When you pick up any book on the brain,” says Eagleman, “it will inevitably describe the different parts for vision, hearing, decision making and so on. That’s so the wrong way to do it. For years I’ve been thinking about how to approach a book like this, especially as what we’re looking at is an extremely fluid system that changes itself every moment of its existence.”
There are “literally thousands” of academic papers on brain plasticity, but “there was nothing that brought all this together in a framework to really allow us to think about what this means in terms of how the system operates. So my goal in writing this book was to distil the 30,000 academic papers on the subject down to the principle of what we’re looking at.”
While Eagleman recognises that engineering has taken humans a long way in a short space of time, “I see it as a door that opens into a whole new empire of things to be done that we just haven’t done yet”. He remains convinced that when it comes to our technological evolution we haven’t really started yet.
“Like so many of us, I studied engineering as an undergraduate and was inspired by the fact that we could literally go to the Moon. But later, when I became a biologist, I came to realise that engineering in a century’s time is going to look a lot different from what it does now.”
‘Livewired: The Inside Story of the Ever-changing Brain’ by David Eagleman is from Canongate, £9.99
The Potato Head principle
The brain is a very efficient kind of machine. It is a general-purpose computing device. It sucks up the available signals and determines – nearly optimally – what it can do with them. And that strategy, I propose, frees up Mother Nature to tinker around with different sorts of input channels.
I call this the Potato Head model of evolution. I use this name to emphasize that all the sensors that we know and love – like our eyes and our ears – are merely peripheral plug-and-play devices. You stick them in, and you’re good to go. The brain figures out what to do with the data that come in.
Mother Nature can build new senses simply by building new peripherals. Once she has figured out the operating principles of the brain, she can tinker around with different sorts of input channels to pick up on different energy sources from the world. Information carried by the reflection of electromagnetic radiation is captured by the photon detectors in the eyes. Air compression waves are captured by the sound detectors of the ears. Heat and texture information is gathered by the sensory material we call skin. Chemical signatures are sniffed and licked up by the nose or tongue. And it all gets translated into spikes running around in the dark vault of the skull.
This remarkable ability of the brain to accept sensory input shifts the burden of research and development of new senses to the exterior sensors. In the same way that you can plug in an arbitrary nose or eyes or mouth for Potato Head, likewise does nature plug a wide variety of instruments into the brain for the purpose of detecting energy sources in the outside world, much in the same way that you add plug-and-play peripheral devices to your computer.
Edited extract from ‘Livewired: The Inside Story of the Ever-changing Brain’ by David Eagleman, reproduced with permission.
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