David Linden: The Brain is a 'Freaking Mess'

"What a piece of work is a man!" remarks Hamlet. "How noble in reason, how infinite in faculty!" And yet man, this "paragon of animals," is no source of delight to Shakespeare's contemplative prince.

One can hardly blame him.

Consider what a "freaking mess" the human brain is, after all. David Linden, professor of neuroscience at Johns Hopkins University, peers into the hardware that man has been given, and finds the most primitive operating system:

We have two visual systems in our brain, a subconscious one and a conscious one. We have two auditory systems in our brain, a subconscious one and a conscious one. No engineer ever would have designed it like this.

No wonder that Hamlet, plagued as he is by visions of ghosts and thoughts of suicide, has such a difficult time sorting things out. He has to take in information from two different streams and fuse them together. That's what creates our behavior.

And so if God designed our brain, you could call him a really bad engineer. Or, to put it another way, as François Jacob famously said, evolution is a tinkerer and not an engineer. When you're a tinkerer, David Linden explains, "you throw things together to solve the problem at hand. You don't build elegantly and you don't build the way an engineer would build to try to consider all the possible contingencies. You're just solving the one problem that circumstances have dealt you at this moment."

That is why we should avoid falling into the trap of believing that just because something evolved means that it is useful to us today. Our brains are impressive, Linden says. But the engineering behind the brain "is completely insane."

Transcript--

There are a lot of things that are created accidentally in evolution. There are a lot of side effects. So you can evolve a pleasure circuit for adaptive things so they will eat food and drink water and have sex. And you can evolve social cognition and then you can connect up your social cognition center with your pleasure center. And then you can take pleasure from positive social evaluation, which is something that you can imagine would promote group cohesion and in hunter/gatherer societies would be adaptive. But then you've built a machine that can be operated on in all kinds of ways in terms of culture and behavior.

And we shouldn't fall into the trap and think that all those ways are adaptive or useful just because they've evolved. Evolution is a tinkerer and not an engineer as Francoise Jacob famously said. And when you're a tinkerer, you throw things together to solve the problem at hand. You don't build elegantly and you don't build the way an engineer would build to try to consider all the possible contingencies. You're just solving the one problem that circumstances have dealt you at this moment.

There's a tendency, particularly when looking at brain function to be over awed by the brain and, well, this is understandable. We say, well, human consciousness is manifest in this two-and-a-half pounds of tissue in our skull and that's amazing. You say, that's amazing, but that doesn't mean that when you lift the hood and look at how its built, either anatomically or electrically or genetically, that what you see is well-engineered. No. It's a freaking mess in there. And it's a freaking mess both at these biological levels and a lot of times it's a freaking mess at the behavioral level.

We have two visual systems in our brain, a subconscious one and a conscious one. We have two auditory systems in our brain, a subconscious one and a conscious one. No engineer ever would have designed it like this.

And then, the information from these two streams have to be fused to create our behavior. It's a total kluge, it works pretty well. Our brains are pretty impressive in what they can do. The engineering behind it is completely insane. It never is what anyone would have designed given the chance, with all the time in the world on a blank sheet of paper.

Directed/Produced by Jonathan Fowler, Elizabeth Rodd, and Dillon Fitton