A Neuroscientist Explores The Illogical Behaviors Of The Mind In 'Idiot Brain'

Dean Burnett says the human brain is like a computer that files information in a way that defies logic. According to Burnett, brains can alter memory, cause motion sickness and affect intelligence.

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. People often think of the brain as being like a computer. But according to my guest, neuroscientist Dean Burnett, that's only true if you imagine a computer that decided some information in its memory was more important than other information for reasons that were never made clear or a computer that filed information in a manner that didn't make any logical sense or a computer that kept opening your more personal and embarrassing files without being asked.

Burnett is the author of the new book "Idiot Brain: What Your Head Is Really Up To." It focuses on some of the more illogical behaviors the brain produces. He lives in Wales, where he's based at Cardiff University's Center for Medical Education and teaches in the psychiatry department. He writes the science blog "Brain Flapping" for the British newspaper The Guardian. Dean Burnett, welcome to FRESH AIR.

DEAN BURNETT: Thank you for having me.

GROSS: So in that analogy that you make between the brain and a computer, you say your brain would be like a computer that decided it didn't really like the information you'd stored. So the computer altered it for you - to suit your purposes, to suit your preferences. And you say your memory is egotistical - that the brain tweaks and adjusts the information it stores to make you look better. What's an example of what you mean there?

BURNETT: Well, I think the classic example is like someone claiming they caught a fish this big, holding their arms out. And oh, the obvious joke is that they didn't really. That's actually just exaggeration. But all of you will think that's just someone lying to try and look better.

But a lot of research suggests that we actually - whenever we remember something, we will tend to embellish if we're telling someone about it. We'll embellish it slightly to make us look a bit better. Or we'll make it a bit more impressive as a story. But every time you do that, the memory itself - it's got a good chance of itself being edited. It's being adjusted.

So the actual underlying memory is replaced by this updated version that you have created to convey something which makes you look better. And that seems to be happening constantly - that we think back on things and we sort of interpret them in different ways to make us feel better about ourselves - make us feel more accomplished, more involved, more capable and more important than we actually were. Because our memory is the only record of it, that often goes unnoticed.

GROSS: In writing about memory, you write about the difference between short-term memory and long-term memory. And short-term memory really doesn't hold very much. I mean, from how you describe it, it holds less than I even thought.

BURNETT: Yeah. That's sort of one of those mainstream ideas of how memory is structured and works, which is not quite correct - in that short-term memory - you see a lot of films and, like, TV shows. They sort of portray short-term memory as something from an hour ago or, like, that same day. Where it's actually - short-term memory is 30 seconds to a minute. Anything longer than that tends to actually now be officially a long-term memory 'cause it takes the brain...

GROSS: Whoa whoa whoa. Anything longer than a minute is officially long-term memory?

BURNETT: Essentially, yes.

GROSS: That means my long-term memory is worse than I thought (laughter).

BURNETT: Yeah. It's a strange - 'cause short-term memory is essentially patterns of activity in places like the frontal cortex. It's like a firework display. Or, like, I liken it to writing - like writing a shopping list in the foam on your coffee. You can sort of do it. And it's something that'll stay legible for a minute.

But generally, quickly, it'll fade away, whereas a long-term memory actually is, like, the neurons and the brain cells connecting together to form a new memory. But that takes time. That takes like 30 seconds to a minute for that to actually be achieved and the stories to actually happen.

So in the interim, we have this short-term memory, which is sort of holding the pattern just in place, waiting for the memory to be formed or for the information to be replaced. And that you can - you obviously know that happens a lot because when you sort of get up to go to the kitchen to get something, and then when you get there, you think, why am I in here now? - and then you have no - you can't remember why you came in there in the first place.

All you know is that you're there now. And that's, like, an example of a short-term memory being sort of lost rather than - it's stored - despite the fact that you actually have acted on it already.

GROSS: So I found this very interesting. You say in your book that there's evidence to suggest that nearly everything we experience is stored in long-term memory in some form. And here's why I find that interesting. This is the kind of thing that happens to me a lot. Like, one of our producers will come up to me and say, do you know that blah, blah, blah, blah, blah, blah, blah? And then I'll say, in all honesty, that sounds familiar. I don't know if I know that.

(LAUGHTER)

BURNETT: Yeah.

GROSS: And as my producer starts explaining, I slowly start to remember that yeah, I did know that. And I realize that I once knew this thing. Then I'd forgotten it. But there's still some kind of vague imprint of that memory in my mind. And the more I hear about it, the more the memory starts to resurface. Is that what you're talking about?

BURNETT: Yeah, that's quite a lot of evidence to suggest that there is different types of memory - something called familiarity and the difference between that and recall - 'cause with familiarity, it's like you say you know you know something. But you don't have any more information than that. All you know is that this has been encountered previously.

GROSS: Yes (laughter).

BURNETT: Yeah. So again, like, using the computer analogy - if you do a Google search, and then some things pop up and some of them are, like, already purple, it's - oh, I've been to that site before. You don't know what that site has on it. You don't know what it was for. It could be something dodgy. Maybe you were drunk at the time. I don't know. But you just know that you've been there before.

But it's when you actually open, like, the file or open the store that you actually understand what's going on in there. So it's the same - like the name thing again - or, like, when you meet someone and they have a very familiar face. You think, I know this person. I know - why do I know them?

And then they'll tell you some details and then fill in, say a few more things. And they'll say something. And you go, oh, yes. That's why - because at that point, there's enough familiarities occurred to sort of reach the threshold - the recall threshold - where it's not just knowing you have the memory. Now the memory itself is actually activated. And it all comes flooding back.

It's a very strange sensation of, like - oh, yes. And I remember all that. And they all - the actual memory itself is triggered 'cause enough familiarity happened. So the activity leading to that memory has gone past a certain point. And the whole thing is set off. And we have, like, the vivid experiences coming back to you. Oh, yes. I met him here. And then we did that. And that was 10 years ago - and so on, so on, so on.

So there are lots of - the brain has a good sort of rule of thumb for new and old. Like, that's a new thing. That's an old thing. That's a new thing. That's an old thing - because when you actually need the detail information itself, that's when you need to trigger the recall threshold, for want of a better description.

GROSS: OK. So the downside for me is I have a lot of memories that I will only remember if somebody tells me that information again. And then it'll start to surface. So on the downside, I've forgotten that memory. But on the positive side, once I hear it the second time, I think I'm more likely to remember it and keep it as a more permanent memory. Am I deluding myself or is that neurologically probable?

BURNETT: No. That makes perfect sense because we remember certain things and not other things. And that's sort of a constant problem because we'd like to remember the things - like if you're revising for a test or an exam. That's the stuff you want to remember.

But abstract information, which is just like intangible data - that isn't something the brain has really evolved to process. It can do it. But it's not its preferred form of information. It's more about experiences and things with a strong emotional attachment - any emotionally vivid memories like your first bike, you know, your first date with your partner, your wedding day. These are all things which have strong emotional resonance.

So they have a lot more attachments in the brain. Like, every single memory has lots of different links to it. So there are lots of different ways to trigger it. So if you have, like, an old memory which you don't actually - haven't really thought about. That's fair enough. So it's got a limited amount of connections to make it accessible. But then when you - no - are reminded of it by talking to a person, you go, oh, yes. So then it all comes flooding back.

That's a new sensation. That's - now you associate that memory with this experience of not being able to remember something and then remembering the person, then being happy that you remembered them. So, you know, you're forming lots of new connections to it. So that actually does make perfect sense in that the act of having a sudden, vivid recollection would, in fact, increase the likelihood that the memory will be more a bit more resilient from then on.

GROSS: If you're just joining us, my guest is neurologist Dean Burnett. He's the author of the new book "Idiot Brain: What Your Head Is Really Up To." Let's take a short break. And then we'll talk some more. This is FRESH AIR.

(SOUNDBITE OF MUSIC)

GROSS: This is FRESH AIR. And if you're just joining us, my guest is neurologist Dean Burnett, author of the new book "Idiot Brain." He's based at the University of Cardiff Centre for Medical Education, and he's a lecturer in psychiatry and writes a blog for The Guardian called "Brain Flapping."

So it's summertime, which means a lot of people are going on vacation, and a lot of those vacationers are going to be driving, many of them with children in the car. And I think children are especially prone to motion sickness. You have a very interesting explanation for why we can get motion sickness in a moving vehicle.

BURNETT: Yes. It's one of those things which people - it's such a common thing, I think a lot of people don't give it much thought. But when you think about it, moving shouldn't make us sick. We move around all the time. We're a very mobile species. So why - you know, why would moving suddenly make us want to throw up? And one theory is - and that's the most salient theory at the moment - is that it's caused by a sensory confusion in the brain and that when you're walking - you know, like us humans tend to do a lot - there's a lot of distinct signals being relayed to the brain that can - like the thalamus, where all the sensory information is put together and sort of, you know, fed to the other parts of the brain. So when you're walking, you've got this, oh, the left, right, up, down sort of sensation.

You've got the muscular system doing its thing and relaying all the signals to the brain. And you've also got the balance sensors in your ears, like, little tiny little tubes full of fluid. And the motion of that fluid tells us where we're going. So, like, if we're upside down, we can tell. And if we're going fast, we can tell because this fluid just obeys the laws of physics. And also, you've got your eyes, and the world's going past at a certain rate. All these things are sensory information which is fed into the, like, the thalamus area, which integrates all the sensory information together to give us an opinion or give us a view of what's happening in the world around us. So we think, oh, well I moving. This is good. That's what I should be doing. Excellent, all is well.

When you're in a vehicle - and vehicles aren't something we've really evolved to deal with because, obviously, they're a very, very recent addition to the world, and evolution takes a long time to catch up with anything. So when we're in a vehicle like a car or a train or a ship especially, you're not actually physically moving. Your body is still. You're sat down. Like, say you've got no signals from the muscles saying we are moving right now. Your muscles are saying we are stationary. And also your eyes - if you are sitting in a ship, like, you're looking at a static environment, so there's no information for the eyes to say we are moving. It's just, oh, everything is still.

But the fluids in your ears, they obey the laws of physics. And they are sort of rocking and around and sloshing because you are actually moving. So what's happening there is the brain's getting mixed messages. It's getting signals from the muscles and the eyes saying we are still and signals from the balance sensors saying we're in motion. Both of these cannot be correct. There's a sensory mismatch there. And in evolutionary terms, the only thing that can cause a sensory mismatch like that is a neurotoxin or poison. So the brain thinks, essentially, it's been being poisoned. When it's been poisoned, the first thing it does is get rid of the poison, aka throwing up.

And as a result - so, like, as soon as the brain gets confused by anything like that, it says, oh, I don't know what to do, so just be sick, just in case. And as a result, we get motion sickness because of the brain's constantly worried about being poisoned.

GROSS: Oh, and it is so incredibly not helpful - not your explanation, but...

(LAUGHTER)

GROSS: ...The sickness.

BURNETT: No, it's...

GROSS: So....

BURNETT: ...Inconvenient to say the least.

GROSS: So I think it's true that you're more likely to get motion sickness if you're reading in a moving vehicle, not an airplane? This is what I found to be true, just that queasy feeling. I know - like, when I was growing up, I could not read in a car. I could not read in a bus. But I could read in a train, and I could read in a plane.

BURNETT: Is that a Dr. Seuss book?

GROSS: (Laughter) Yes, yes it is.

BURNETT: (Laughter) Could you, could you, on a plane? Could you, could you in a train?

GROSS: (Laughter) So is there any - I'm assuming that this is a common experience, and it's not just me. But perhaps it's just me.

BURNETT: Well, it makes - again, given the explanation I provide, that does make perfect sense because you are - it's not just you're in the vehicle now. When you're reading a book, you are staring at something right in front of you, so you're shutting out a lot of external visual information. Now when you're in a car - a lot of people don't get motion sickness because the brain can effectively intuit this, though some people just are prone to it. It's just a quirk of development.

But you - when you're in a car, you can look out the window. You can see things going by. You can see the passage and movement itself, so that sort of balances the system. The brain's going, oh, look, things moving - I must be moving - and then sort of calms down the sickness response.

But when you're reading, you're looking at sort of a small, static square. And, you know, the external information which would say you're moving, that's shut out even more than it would otherwise be. And you're focusing straight ahead, and your vision's directed elsewhere. So it sort of increases the sensory mismatch, which is causing the sickness in the first place because you are sort of dead - you're looking at a fixed point. And you've got no visual information to try and help, you know, allay the brain's concerns. So yeah, that would make perfect sense.

GROSS: So I think a lot of people outgrow motion sickness. And is that because your brain, over time, adjusts to the mixed message that it's getting when the vehicle is moving, but your body is staying still?

BURNETT: That's probably what's happening, yeah? It's - children are - generally tend to be more prone to things like - which are involve, technically, the brain getting things wrong, things like sleepwalking. Children are far more prone to sleepwalking and things like that and motion sickness. That's because their brains are still developing. They're still being shored up. They're still being refined. They're still forming all the connections they will need for the rest of their lives.

And - this means their systems aren't so efficient yet. So gradually and over time, they will sort of lose the excessive part. They'll refine the more useful components. And as a result, like, the more - the less helpful things the brain does will sort of be slowly fading away because the brain becomes a bit more focused and a bit more refined and efficient over time as we age.

GROSS: So how much is intelligence based on having a good memory? Like, if you have a hard time remembering things you've learned, then you can't build on those things. You can't use those things to synthesize, you know, an analysis of, you know, a text or politics or whatever. So are memory and intelligence intertwined and dependent on each other?

BURNETT: Yes, to a certain extent. A lot of psychologists differentiate between two types of intelligence. There's crystallized intelligence, which is like things you remember, things you've learned and the information you have access to. So someone on a quiz show, for example, would be - you know, someone who's a champion of a quiz show, they would have very high crystallized intelligence because they can just remember all this information, all these facts and recall them at a moment's notice as and when they need to. So that's a very high crystallized intelligence.

But that's not the only element of intelligence. There's also something we call fluid intelligence. And that's the ability to apply the information, the ability to work with it, the ability to process it. So let's say Sherlock Holmes - like, he's presented with three different things. And he can go ah - put these things together. They show that the killer was there at midnight, and he had a brown dog.

And that's more like fluid intelligence because taking abstract information and processing it and working with it and applying it to the situation in front of you - so crystallized intelligence is, like, the information you have. Fluid intelligence would be your ability to use that information and extrapolate from it and to apply it in real world situations.

So the two are quite different in many ways. Like, fluid intelligence, a lot of research suggests, that declines as we get older just because our brains just age and become slightly less efficient over time with just general wear and tear, whereas crystallized intelligence doesn't seem to have any ceiling on it. It just keeps expanding as we get older, assuming, of course, our brains still keep working as they should and no new degeneration occurs.

GROSS: I thought it was the other way around - that your ability to synthesize things does not decrease with age, but your ability to just kind of, like, memorize things and retrieve facts does.

BURNETT: Well, a lot of people sort of claim that, yes. But a lot of the research suggests that it's actually the other way around in that you can - I think it's more a case of you can't stop remembering things. Like, you don't reach the age 65 and suddenly don't remember anything from that point on because, obviously, that's not what happens, unless you have some sort of serious disorder, of course.

But, anyway, you can carry on building up information over time. When you're 80 years old, you remember what happened yesterday or the day before. And you remember way to go, and you remember your appointments. So you can still build on the crystallized intelligence. It's just that the parts which process information tend to get a bit rusty. So that - according to the science, that's one argument anyway. But as I say in the book a lot, with most neuroscience claims and studies, you'll find another one which says the opposite pretty easily because it's a very confusing organ.

GROSS: Do you think of yourself as having a good memory?

BURNETT: I think I would say that I do have a good memory, but not for everything because, like, the brain does seem to have a tendency to specialize or to have preferences for the things it likes to remember in its process. Some people are better at maths. Some people are better at music and things, whereas I, too, I guess, tend to have a good memory for episodes of "The Simpsons" or jokes I've heard or people I've met recently and, like, anecdotes. But things like household organization and bills to pay, I tend to have a rather poor memory for these things as my wife will constantly tell me. So yeah, I have good memory in some ways and not in others.

GROSS: So you write a blog for The Guardian called "Brain Flapping."

BURNETT: Yeah.

GROSS: What's the most commented on post that you've written?

BURNETT: This - it came as a surprise the first time, but it shouldn't have in hindsight. I've written about a lot of things like trying to deal with some controversial subjects like transgender issues - that was quite a hot-button one and immigration, whether it's good or bad; and same-sex marriage got a lot of responses. But the most controversial post I did in terms of the most angry comments I got was whether or not you should put milk in your tea before the water or after.

GROSS: (Laughter).

BURNETT: That is such - it was the most British thing you'll ever hear, I know. But that is like - that was the most - even my parents got involved in that one, which they never normally do.

GROSS: Wait. So what was your argument?

BURNETT: Well, there's a study which says you should put milk in first, but that actually only applies to if you use it from a teapot in a sort of bone china cup because, obviously, it takes the heat off the tea so the cup doesn't fracture. But if you use a mug, then it's a different process, and it went down into the chemistry of it. And it came down to the fact that you should put it first or last, depends on how you like it because it's all about taste perception and the ritual and the psychology behind it.

But that diplomatic copout wasn't enough for some people. They decided that I should hear, in no uncertain terms, how wrong I was.

GROSS: So which do you do?

BURNETT: Me, I put milk in second actually. But I might actually be kicked out of the country for this, but I can't tell either way. And that's not something a British person wants to hear. But yes, I'm not actually fussed either way. I can take it both ways.

GROSS: Nice to know that tea is click bait in England.

BURNETT: (Laughter) Very much so.

GROSS: Dean Burnett, thank you so much for talking with us.

BURNETT: No problem at all. Thank you very much for having me, Terry.

GROSS: Dean Burnett is the author of the book "Idiot Brain: What Your Head Is Really Up To." He writes the science blog "Brain Flapping" for the British newspaper The Guardian. After we take a short break, we'll hear from comic Ali Wong whose comedy special is frank and funny on subjects ranging from being Asian-American to her sex life and being pregnant. I'm Terry Gross, and this is FRESH AIR.

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