Dean Burnett doesn't think the human brain is so great. He thinks it's messy, sloppy and, sometimes, downright annoying.
The Welsh neuroscientist, who writes the popular science blog "Brain flapping" for the Guardian newspaper, was tired of seeing typical books on neuroscience treat the brain as a mysterious, revered and almost mystical organ. So, Burnett decided to knock it off its pedestal in his new book, The Idiot Brain: A Neuroscientist Explains What Your Head is Really Up To.
Burnett is also a stand-up comedian, and he tackles his subject with a screwy sense of humour. His book offers a light, easy introduction to how the brain works. It also provides plenty of quirky tidbits, such as how phobias develop, why we remember faces before names, and why people "see stars" after being hit in the head.
It's the kind of stuff you can repeat at dinner parties to make you look smarter – provided that your idiot brain can remember them.
Burnett spoke with us over the phone from Cardiff about how the brain manages to mangle even basic functions, such as visual perception.
After a blow to the head, why do people "see stars"?
The occipital lobe at the back of the brain – it looks a bit like buttocks, very wrinkly ones – that's the main bit that processes sight. That's the visual cortex, essentially, so one of the possibilities is if you're hit in the back of the head, enough force is applied to that part of the brain, providing stimulation. But it's not carefully controlled stimulation, it's just blunt force. The brain doesn't know what to do with it, so it just disgorges these weird patterns we see.
Or if we're hit on the front of the head, there's a thing called coup and contrecoup. The brain isn't rigidly fixed in your head. There's a bit of give to it. It bounces around in the skull, so it hits one side and then the back end hits the skull. Either way, you get this weird stimulation of the visual cortex. The brain tries to make sense of it, but it can't because, obviously, there is no actual sense to it, so it just sees blotches and patterns of colours and you interpret that as stars.
Why does Jesus appear in pieces of toast?
There's a thing called apophenia. It's a very persistent illusion. You get all this sensory information flowing in at all times and most of it is irrelevant. So the brain has to work out a quick way to try and refine or localize the important stuff. One way it does that is to look for patterns in stimulation. It can in anything really, any sort of sensory information or occurrence of events.
When it comes to the visual system, which is the most dominant sense by a large margin, it looks for patterns in everything and anything, which aren't necessarily "there." So when you see things with a lot of contrast, like toast or any sort of baked or grilled food, you have dark patches and the brain just looks at it and says: "Oh, there's Jesus, there's Elvis, there's a smiley face, there's your mother."
Why do people experience motion sickness?
Motion sickness is a weird one. The main theory is that it's a disparity in the information in our brains. When we're in motion, our brains are receiving lots of different signals. The vision system is showing us that the world is passing by at a certain rate. The balance system in our ears is telling us we're in motion; the gravity, force and physics affect these balance sensors. And if we're walking around, there are all these muscle sensations. So all of these systems are feeding information into the more fundamental aspects of the brain, like the thalamus. And that extrapolates all of this and says, "Okay, we are in motion." And the brain is cool with that.
But artificial transportation in vehicles is a very recent human achievement in evolutionary terms. And the more fundamental aspects of the brain haven't had a lot of time to deal with that. So if we're on a ship or something, especially if we're inside the ship, the eyes are telling us: We're fine, we're calm, we're steady. Whereas the balance sensors in your ears are saying: We're going up, we're going down, we're going left, we're going right. So, the brain is getting two completely contradictory pieces of information. And the primitive part of the brain can't work out how that can happen. In nature, the only way that can happen is if we've been poisoned. So the brain goes: "Just throw up! Throw up now!"
But blind people can also get motion sickness, so there are also theories that the mode of travel is likely stretching the facial nerve, the vagus nerve, which is also providing weird information to the brain. So it thinks: "That doesn't happen normally, so it must be poison." It all boils down to the brain thinking we're being poisoned when we haven't been.
How do we sometimes fail to see things that are right under our nose?
The human attention system is a lot more limited than people really appreciate. It's not like it's weak or little or pathetic. It's just that we deal with so much sensory information, the brain only has a certain amount of capacity to isolate our attention stream; so, we look at this thing or that thing.
If we focus on something quite intently, all our resources are dedicated to that, whatever that may be. For example, if you're flying a plane, you might miss something going on outside the window. It's in your periphery, but you're not actually focusing on it enough to be distracted.
There are some things that can distract us. So, say if you're reading a book and a UFO appears overhead, you will pay attention to that. When there's something that's completely outside your realm of expectation, your brain goes: What, what, what?! But in your day-to-day life, it's very hard to shift your attention once it's being applied to something that you're still in the middle of doing.
This interview has been condensed and edited.