CHRISTMAS LECTURES 2011: Bruce Hood - Who's in charge here anyway?

The second Christmas Lecture with Professor Bruce Hood.

Who's in control - you or your brain? Your conscious thoughts are only the tip of the iceberg when it comes to all the activity going on inside your head. Every minute your brain is bombarded with information - sights, sounds, smells, feelings - and you are aware of only a tiny fraction of it. How does your brain decide what to trust and what to ignore, all without you even knowing? What sneaky shortcuts does it take to speed up your mental ability? Why is multi-tasking so dangerous?

Using some surprising illusions and lots of audience participation, Bruce makes you say the wrong thing and fail to see what's right in front of you. Can you really believe your eyes? Possibly not!

Themes

Being Human

Details

Type:
Christmas Lecture
People:
Professor Bruce Hood
Location:
London, UK
Filmed in:
The Theatre
Published:
2012
Filmed:
2011
Credits:

BBC

Collections with this video:
CHRISTMAS LECTURES 2011 - Meet your Brain

Licence: © 2011 The Royal Institution

Comments

Transcript

Watch this. I've been practicing at least two months. Darn. Why won't my brain let me juggle?

[APPLAUSE]

Welcome to the 2011 Royal Institution Christmas Lectures. I'm Bruce Hood. I'm a scientist, not a juggler as you've just seen. In tonight's lecture, we're going to look at how the brain works.

Now I wasn't born to juggle. And it's hard, because it requires coordination. And if you lose concentration, everything just falls apart. But it is a skill that you can acquire. All of us have the potential to gain new skills like juggling or improve on the ones that we have. And this is because we have brains that are flexible, brains that are adaptive, brains that can learn.

In tonight's lecture we're going to look at how the brain learns. Because learning is what makes us intelligent. As human beings, much of who we are is how we learn. All the memories, all the actions, all the experiences, shape us.

Now there's a lot of stuff out there to learn. And we have to make choices. So how does our brain make those decisions? Who's in charge here anyway?

We're going to start by investigating a key aspect of this - our memory. Ladies and gentlemen, give a very warm welcome to someone who has one of the world's best memories. He's been world memory champion eight times, Dominic O'Brien.

[APPLAUSE]

Well, Dominic, we gave out a pack of 52 cards to the children before the lecture started. And we got them to write their name and their birthday on that card. And then we gave you the same cards for you to memorise. So do you think you've been able to do that?

Well, in the time I had, there's a lot of information there, three lots of sequences and dates. It's all jumbled up in my head. But I think I've got a hold of it.

OK, so let's put you to the test. So I'm going to blindfold you just so you don't recognise the children. So would you mind taking the blindfold, and you pop that on. And when that's on, I'm going to get the children who have the playing cards that we gave out earlier to stand up. So the children that have the playing cards, stand up please. Oh wow, OK.

So I'm just going to select one at random. How about you? Just hold up your card and just say what the card is. The nine of hearts. Dominic, the nine of hearts.

The nine of hearts. Is your name Iona? And is your birthday the 30th of September?

Is that correct? OK, let's try another.

[APPLAUSE]

Sir, hold up your card. Eight of clubs.

Oh, we're doing it that way around. OK. Eight of clubs. Is your name Nick? And your birthday I think is in December. Is that right? Is it the 6th of December?

Yes.

Good. Well done.

[APPLAUSE]

Sir, with the white t-shirt, what's your card?

Three of clubs.

Three of clubs. Let's start with your birthday. I think you were born in January. The 19th of January. And your name is Charlie.

Is that right?

Yes.

[APPLAUSE]

Round of applause. OK. Congratulations. Dominic, that's amazing. We're going to have to find out how you do that. Would you mind coming back later on and explaining the secret?

I'll reveal some of the secrets later.

Round of applause for Dominic.

[APPLAUSE]

Please that a seat, everyone. So does Dominic have a special brain? Is he sort of from outer space? No. He has a normal brain. And you all have the potential to train your brain to be as good as Dominic's to acquire new information. But how do you go about this?

Well, it's all to do with learning. Learning takes place whenever we remember experiences from the past. Each time you encounter an experience, this creates a pattern of electrical activity in your brain. And the memories are these patterns of electrical activity in the connections between the brain cells called the neurons.

Now when you repeat experiences, you're repeating the patterns of firing until it becomes familiar. Your brain is simply recognising similar events. This explains why you often don't notice things that you've encountered many times. Because your brain has got it well encoded and got used to it.

But it also explains why you suddenly notice something that you did not expect.

[BANG]

[SCREAMS, GASPS, LAUGHTER]

[APPLAUSE]

So your brain was alerted to this new experience. The warning bells were set off telling you to pay special attention to deal with what could be a potential problem.

However, if I do it again - shall I?

Yes.

Shall I? Yeah? Ready?

[BANG]

[SHOUTS, GASPS]

So this time you expected it and were less bothered. Eventually if I kept pressing it, you wouldn't respond at all. And this is because you've learned it. It's a form of learning called habituation. Your brain has become familiar with the event, and you anticipate it.

Even animals with very simple brains can learn through habituation. And we know this is learning due to change in the connections in the brain. But you don't have to be aware. Habituation's a type of learning that's unconscious. You don't have to think about it. The brain is simply processing and storing experiences without you even realising it.

But what's remarkable is that this kind of unconscious learning is at the very heart of one of our most sophisticated and unique abilities as a species - our ability to learn language. Because if you think about it, we don't actually teach our babies to speak at first. And yet, most babies learn their first words by their first birthdays. In fact, any baby has a potential to learn any language wherever it's raised in the world.

Is the baby really trying to learn the language? Well, I don't really think so. I think their brains are programmed to rapidly encode the languages they hear. But this ability deteriorates as you get older. So I'm going to test this audience. Let's test how good you are at telling the difference between languages that you maybe have never heard before.

First of all, listen to these sounds from the English language. This is me speaking. See if they tell the same or the difference. Bah. Dah. Are they the same? Hands up if you think they're the same. And hands up if you think they're different.

OK, let's try these next two.

Dock. Duck.

Are they the same or are they different?

Now actually, do I have any Hindi speakers here? Are they the same or different? And your name is?

Preeta

Preeta. And what's the first word?

It's dock. Can you say it, because we can't hear very well?

Oh, dock. It's doh. It's not duh. And the second one's duck. And it's duh, not doh.

And what do they mean?

First one means till tomorrow.

Until tomorrow.

Yeah, and the second one doesn't mean anything.

It doesn't mean anything at all. It's not even a word. Can we hear it one more time?

Dock. Duck.

So the first sound means till, as in till tomorrow. And the second word is just nonsense. But to us, we can't hear the difference. It's quite remarkable. Unless you heard Hindi as a baby, you wouldn't know it.

So this ability to encode information of early experiences is called plasticity, brain plasticity, which comes from the Greek to be moulded. So when you're born, you have almost all the neurons you'll ever have in your brain. There's about 100 billion of them. It's just that they're not connected up yet.

So let me show you with a diagram a model of my brain. So this is a picture of me as a baby.

[LAUGHTER] Yes, it's my christening dress. And as you can see, I'm very happy. It is actually me. Now here's a model of my brain. Now each one of these little nodes here, these are the neurons I was telling you about, the brain cells.

And between the neurons are the connections, which are the dendrites, which are the ways that the neurons talk to each other. So when you're born as a newborn, there's very few connections. Now this is me at six months. Now don't laugh.

[LAUGHTER]

I knew that was coming. OK, now here's the brain model of my brain. Again, we have these same neurons, but there's actually many more connections now. It's as if the neurons are wiring itself up. The brain's sending out the communications telling the brain cells to talk to each other. But in fact, there's almost the same number of brain cells. As I said, you have almost all the brain cells you'll ever have as a baby.

And here is me as a three-year-old.

[LAUGHTER]

Something about me not wearing clothes, OK, I get it. It was hot. It was. And here is my brain. Now look at the brain model here. Again, we have the same number brain cells.

But look, the connections are much thicker, because the brain cells are communicating. And as they communicate with each other, these connections become thicker. And this connection, this thickening, reflects the experience as the brain is moulding itself to the world around it.

But whether it actually forms connections or not depends on experience. If you never experience events, then the connections never come. And this is because you lose them. Effectively, the brain, if it doesn't get the experience, prunes back those connections to make it more efficient. In this way, the brain is moulding itself in becoming much more tuned into the environment.

Now many aspects of pruning happen early childhood, which is one of the reasons why our brains are much better when you're younger for learning new skills that older brains. This partly explains the saying, it's hard to teach an old dog new tricks.

Now when it comes to neural connections, the brain needs to keep them active or they wither away. In other words, you have to use them or you lose them.

So someone mentioned earlier the urban myth that you only use 10% of your brain. It can't possibly be true. Because if you weren't using those parts of your brain, then they would wither away. And without 90% of your brain, you'd be in a lot of trouble.

Now when early connections are formed, they can lead to long term consequences. And what happens when I play this?

[MUSIC PLAYING]

Anybody else fancy an ice cream? Well, to me, when I hear that, I think about ice cream and my mouth starts to water and salivate. And that's because when I was a child, I used to buy ice creams from a van. They used to play those sorts of jingles. So just the sound of that stays with me.

And when I'm an adult now, my mouth starts to water, because I'm anticipating the ice cream I'm about to have. It's a classic Pavlovian response, named after the famous Russian scientist Ivan Pavlov.

And Ivan Pavlov was working on the digestive system of dogs when he discovered that if you flash the light or rang a bell at the same time you delivered the food, the dogs would associate the light to the food and begin to salivate, even though there was no food there. Pavlov proved that sights and sounds that don't normally signal food can be learned by repeated association, to trigger our stomachs and mouths and make our mouths water.

So the brain is learned by associating different neural patterns. One thing should lead to another. So this explains why you feel hungry when you're in the playground and you hear the dinner bell ringing. Salivating is an automatic behavior.

However, many behaviors, especially those in higher animals, are not automatic. And they can be shaped through training. So let's meet one of Britain's best examples of training. Ladies and gentleman, a big round of applause for Morgan and Venetia.

[APPLAUSE]

OK, good boy. Wait.

So this is Morgan?

Yes.

Let's see what Morgan can really do.

Right. Through. Come. Round. Round. Round. Ready? Good.

[CLICK]

Good boy. Weave. Come on, click. Weave. Weave. Weave. Click.

[CLICK] Wiggle. Wiggle. Wiggle. Wiggle. Wiggle. Wiggle. Good. Twist. Come through. Round. Middle. Middle. Twist. Twist. High.

Hooray!

[APPLAUSE]

Very good. So everyone would like to know, what kind of breed is Morgan?

He's a Border Collie.

And how old is he?

He's three and a half.

Right, and you've trained him to dance, I take it.

Yes, from a puppy.

Now how do you do that?

Well, I use a clicker. And from eight weeks old, we just teach him the basics of sit, give a paw, and any other commands. Something very, very simple.

So when he hears a click, then what do you do?

Well, while he's actually doing the process - twist [CLICK] - you've got to do it while they're in the middle of doing the process rather than wait to the end. Twirly. [CLICK] Good boy.

So Morgan has learned to associate the sound with a reward.

That's right.

And you can use this to shape his behavior.

Yes, yes. And once they've learned through the clicker, then I use my voice. And I don't need to use the clicker after that. And he gets to know the commands.

That's fascinating. Can we give a big round of applause for Morgan and Venetia?

[APPLAUSE]

Well, that's one dog that can learn new tricks. Morgan learned his amazing skills through training. After all, he would never have taught himself to dance by his own. He's learnt this because Venetia has trained him with a clicker and association to shape his behavior.

Now humans can also be trained. But as a social animal, there's also other things that motivate our learning such as rewards, seeking praise from other people. In fact, as humans, our behavior is often motivated by our own personal goals. So the skills and information that we learn are stored as memories in our brain.

Now initially, the first stage of storage is in the short-term memory. It's a sort of kind of temporary holding bay. But there's a limit to how much information you can hold and how long you can hold it for. So let's test someone's short-term memory. Who wants to be a volunteer in a memory test? I think we're going to go for the gentleman in the orange. Would you like to come on down?

[APPLAUSE]

So what's your name, sir?

I'm Tom.

You're Tom. OK, how old are you, Tom?

I'm 11.

OK, Tom, would you like to take a seat? Because we're going to test your memory. And we're going to show you a lot of items. And I want you to remember as many as possible. And I'm going to be assisted by Thalia who will be keeping track of all the items that you remember. Because after you've seen them all, we're going to ask you to recall as many as possible. You think you're up to that?

I'll try.

All right, try your best. OK, are you ready? OK, I'll stand back. And let's start the game. A pound coin. A diamond lattice. A skull. A cuddly toy. A hose. A pair of die. A broom. A hat. A ball. A red hat. A yellow bucket. A garden blaster thing. A kettle. A camcorder. A truck. A mirror. Juggling balls. An alarm clock. The world. A tire. A member of the audience. OK, well done.

OK, now I'm going to test your memory. OK, quiet everyone, because this is going to be very hard. Are you ready? In 30 seconds, can you remember as many items as possible? Ready, go.

Die, a skull, a broom, a coin, there was a member of the audience.

Yes.

There was a kind of atom thing at the very beginning.

An atom thing at the very beginning. A diamond lattice. 15 seconds.

There was a blower thing.

A blower thing, the odd thing. Oh, well done! Didn't he do well?

[APPLAUSE]

So Thalia, let's see how Tom did. OK, let's turn it around. Now this is very interesting. This is very typical for this kind of test. What Tom remembered was, of course, everything at the beginning - a giant pound, the diamond lattice, and the skull - because he'd just begun the test. And he also remembered the item at the end, partly because it was funny, but also it was the last item on the list. Notice how he's forgotten many of the things in the middle. And the one odd thing he remembered was a leaf blower, which is a very odd thing to see.

Now this reflects the fact that you tend to remember things right at the beginning and right the end. And all things which are novel stand out like a sore thumb. So other items like a cuddly toy, when we used to watch this program, was always the thing that people remembered. It's a strange thing to have.

Now this is a very interesting learning lesson. Because if you, for example, want to be remembered and you're taking part in a audition or you're trying to get a job, it's good to be at the beginning of the list or at the end, because we tend to remember those people who start off the interview and at the end. And if you can't be at the beginning or the end, well just be outstanding. Because that's one way -

Hey, stop! Thief!

What the? Oh, I don't know. Another problem tonight. Did anyone see that? How many of you saw that? Hands up if you saw that? [SIGH] OK, clearly we have some very dodgy characters around the Royal Institution Christmas Lecture. I need to get on with the lecture.

Where was I? Oh yeah, memory. Memory, of course, can be easily distracted. And it's not that good, quite poor. So if our short-term memory is so poor and easily disrupted, how did our memory expert at the beginning of the lecture succeed in remembering all those cards? That's really quite remarkable.

Well, the secret to his success is learning through organisation. Try this out. How many of you can remember this number? One, nine, one, four, one, nine, one. Hands up if you think you've got that. Let's test you out. I'm going to try you.

One, nine, one, four, one, nine, one.

OK, good. What about if I give you a second number? How about eight, one, nine, three, nine, one, nine, four, five?

Eight, one, nine, three, one, five?

Can anyone help him out? Three, nine, one, nine, four, five. So the first one - what was the first number, by the way?

[LAUGHTER]

You've completely forgotten. You see, this explains or at least demonstrates how short term memory is very limited. And when you have to remember items which are very similar, you get confused, and you easily forget them.

Now one way to improve that is to chunk them together. So we have a look up here. These are the numbers I was reading to you - one, nine, one, four, one, nine, one, eight, one, nine, three, nine, one, nine, four, five.

Now can anyone see some patterns? Let's just chunk them into smaller groups. And now we've got 1914, 1918, 1939, 1945. Is there any historians in the audience? What are those numbers? What do they stand for? Shout it out. That's right. They just happen to be the start and the end of the World Wars.

Now of course, not all numbers just happen to fall into place as being memorable. But you can organise information into more meaningful patterns to make them easier to remember. And if they don't readily fall into a more memorable pattern, then you can learn to associate them with a pattern that's easier. This is a technique called mnemonics.

Now I've got one you probably know - Richard of York gain battles in vain. Does anyone know what that is? Sir. Colour of the rainbow. Anyone got a mnemonic? Yes, with the hat.

Never eat shredded wheat.

Never eat shredded wheat. What does never eat shredded wheat mean? North, east, south, west. So as you can see, it you organise difficult lists into more memorable phrases, they're much easier to record or recall. And that's because you can remember them much easier.

Even the word mnemonics is a difficult one to spell. And I've got a sentence that makes it easier. For example, if I use my new experience memorising all of names as clearly selected, then you have how to spell the word mnemonics.

So let's get back our memory expert, Dominic, to find out what he's been doing to make such an incredible memory of his. Welcome back, Dominic.

[APPLAUSE]

You've been listening to some of the explanations about how memory can be improved and how we can organise memory. Let us into the secret of your amazing memory.

Exactly what you've just been explaining. I use mnemonics myself, Dominic's mnemonics.

Dominic's mnemonics.

I turn difficult information like playing cards, names, dates, into colourful images. And I also use journeys, sequences to remember the order of whatever it is I'm trying to remember.

For example, I use a golf course to remember all these names. I imagine them at each tee along the golf course. So let's say we've got the jack of clubs. Now I've got to remember that Kate is connected with this, and her birthday is the 20th of October. So what I think about is an old girlfriend of mine called Kate from many years ago. And she's skiing on the first tee. Now why is she skiing? Because I associate the jack of clubs with an old friend of mine who used to be a skiing instructor.

OK, so that's the first two bits of information. To remember the date, the 20th, I think of Barack Obama. Barack Obama, because the second letter of the alphabet is B and at zero is O - BO. Not body odour. That's Barack Obama. And to remember October, I imagine him wrestling with an octopus. So you go to put it all together. It requires a bit of an imagination. I put it all together. But I had to do that 52 times.

Well, and that takes a lot of practice and a lot of organisation. Ladies and gentlemen, that's amazing. Another big round of applause for Dominic. Thank you. Thank you very much.

[APPLAUSE]

Now when you organise your memory like this, you're making it work for you, which is why we sometimes call it a working memory. By working our memory, we can prepare information for storage into long-term memory. And this is really part of a system in this part of the brain that we call the hippocampus.

So I'm just going to take this brain apart to show you, because it's inside the structure here. There we go. So this is one hemisphere. Now let me see what I can show you. This is the front part of the brain. And inside there's all these internal structures. So let me just pop off the front of my brain here. And this is a structure we're really interested in. Let's get this bit out here. This is called the hippocampus.

Now it's shaped a little bit like a seahorse, which is why it's called the hippocampus. Because that comes from the Greek word for seahorse. Now it's the hippocampus we know is really where your long-term memories are stored. Now we're not really sure exactly how all these memories get encoded. But we know this structure must be used because, for example, if you damage it, you lose your long-term memories.

And taxi drivers in London, for example, are very proud of their hippocampi, because there are two of them. Because taxi drivers have enlarged hippocampi. And not only are they larger, but they're more active. And we think this must be due to the fact that when they have to memorise the whole of the streets of London, the knowledge, then they're encoding this information.

And what's remarkable, is the hippocampus or hippocampi are one of the few structures in the brain where you can actually grow new brain cells. Now when you damage this area, you lose your memories. The consequences of damaging your long-term memory can be quite devastating.

I'm sure that many of you may have some relatives who are starting to lose their memory. And it can be a very devastating type of experience. Because when you lose your memory, you effectively lose your identity. Because who we are is really a sum of our memories.

So let's consider our own memories. You guys, what about your autobiographical memories? What the earliest thing that you can remember? Hands up if you can remember being six years of age? Pretty good. Five? Keep them up. Four? Three? Two? One? We got one person with a memory less than one. Do you remember what that memory was by any chance?

It was my first birthday, and I had a party. And it was like my friends from when I was -

It was your first birthday, and you remember the party. Is that right?

Yeah.

But notice how most of you put your hands down when I said two to three years of age. Now why is it that very few of us can remember anything before our second or third birthday? It's not because babies don't have memories. We know they can learn. So it can't be simply the fact they haven't got memory.

It might be related to the fact that the brain isn't very mature in a very young baby. But I think a more interesting possibility is that very young babies don't fully understand the world yet. So it's difficult for them to organise their information into useful memories. Because organisation is really important when it comes to storing these things.

[SIREN BLARING]

Hold on a second. Oh, I've just heard the police have apprehended a suspect in the robbery of the soft toy. You remember the robbery that we had just a moment ago? Hands up if you saw that robbery. Good. And you all got a good look at the suspect? Yep, OK. Yeah, they're coming through now.

OK, so you think that you can identify the suspect? Hands up if you think you can. That's almost all of you. Good, all right. So let's test you out. Because the police need to do a lineup, and you're going to have to pick out who the suspect is, OK? So bring them in sergeant.

All right you horrible lot, get in here now! Form an orderly line! Quick as you can now! Thank you! All present and correct sir. Over to you, professor.

Thank you very much, sergeant. OK, so these are the suspects who are in the lineup. I'll start off your way here. And one of them committed the crime. So let's see if you can identify the criminal. I'm going to ask you to step forward, each suspect. And then I want, with a show of hands, if you think it's the person or not. Will subject A step forward? Miss Behaving. How many of you think it's Miss Behaving? OK, step back please.

Subject B, Miss Demeanor. Hmmm. That's a pretty good show of hands. Subject C, Miss Placed. Not so many. Subject D, Miss Understood. Quite a few for Miss Understood. And subject E, Miss Take.

So the majority of you thought it was B. Now that's very interesting. Not everyone agreed. But let's see if you are right. Will the real culprit step forward please. It was subject A. Big round of applause for those who got subject A.

[APPLAUSE]

All right, sergeant, I think you can take them away.

Very good, sir. All right, you're nicked! The rest of you, very sorry for the inconvenience. Be on your way now. Get out of here.

It was a set up!

So even though you got a good look at the thief, and you thought you would recognise them easily, our memory can be very poor. Studies show that eyewitness testimonies are notoriously unreliable. And this is quite important. Because in some countries, they use this kind of technique to put people into prison. So we really have to question this as a major legal issue.

So memory's not like a photograph. It's not a picture in your mind that you can review. Memories are much more fluid. And that was a test of face recognition.

But I want to test all of you now and those of you at home with a different type of test. I want to test your memory for words. So again, everyone's going to be involved in this one. I'm going to read a list of words. And I want you to try and concentrate and see if you can remember the list I'm reading. OK? Simple enough.

Let's start. Thorn. Thimble. Point. Pen. Eye. Sharp. Injection. Cloth. Haystack. Sewing. Syringe. Knitting. Hurt. Thread.

Now let's test your memory. Hands up if you think I said the word thread. Very good. Hands up if I said the word banana. How about the word needle? Hands up if you're sure I said the word needle. Well, you're in for a surprise. Here are the actual words I said. And nowhere on this list is the word needle.

And yet you are convinced that I actually said the word needle. I implanted a false memory. Because the word needle was triggered by all these other words, which are related to the word needle. So in your brain, this association with the word needle was stimulated.

So what I did was, as I said, I implanted a false memory. Every time you have to remember something, you have to reconstruct it. Build it back from the fragments of information stored in the neural networks of your brain. We've just shown that the brain can have false memories, which raises the original question we asked at the beginning of the lecture.

Because who's in control anyway? If your own memories can be wrong and you don't even realise it and the memories are the key to your identity, well, who are you? Well, that's a pretty big question. And philosophers have been thinking about this for a long, long time. But we know that the answer must lie with the brain. We know this because people can be changed when their brains get damaged.

Back in 1838, [TRAIN WHISTLE] Phineas Gage was working on a railroad as an engineer. And he's blasting the rocks with gunpowder to clear the path for the rail track when a colleague distracted him. And he accidentally [BANG] dropped the rod onto the gunpowder. And it shot the rod straight through his skull and out the top and landed 25 meters away.

Now remarkably, Phineas survived. Now according to the records, he'd lost the front of the part of his brain. Before the accident, he'd been a mild mannered man. But after the accident, his personality changed. He swore more frequently. He became more irritable. And he became emotionally unstable. In short, Phineas Gage was no longer Phineas Gage.

The region that had been damaged was the frontal lobes. And his accident provided a clue to what the frontal lobes do and how important they are to our personality and identity.

Now the frontal lobes are also responsible for flexible thinking and creativity and regulating behaviors that coordinate our activities. The frontal lobes are, in effect, delegating, prioritising jobs, like a chief in your head office. But of course, there's no one really in there. It just feels as if someone's in there making decisions. And that's because our brain generates a sense of ourself. A person in control. The you in your head.

Now you don't have to have a metal rod shot through your head to see the effects of frontal lobe damage. Frontal lobes can be impaired by disease and drugs. And one of the most commonly used drugs is alcohol. Who wants to try out the effects of alcohol? That's the quickest response I've had for a long time. I'm going to choose, sir, would you come down?

[APPLAUSE]

Let's get someone from this side. Any more volunteers? Young lady, come on down.

[APPLAUSE]

OK, let's find out who you are.

I'm Flores.

Flores, OK. And how old are you, Flores?

11.

11. And you want to drink alcohol? And you are?

Oliver.

Oliver. And how old are you, Oliver?

13.

Right, we have a bit of a problem, don't we? Because we can't give you alcohol in this country, can we? You were hoping for some alcohol, yes? Yes? Right, well OK, we're going to have to improvise. And what I'll do, let's imagine. Let me take you to Paris to a cafe. OK, so join me in this cafe. If you come this side.

[FRENCH MUSIC PLAYING]

Flores here, Oliver here. Now I'll be your wine waiter. And sir, I am going to pour you some wine. And I want you to celebrate. Cheers. If I just pour the wine here. Would sir like to try the wine, make sure it's tasty? It's not wine, of course. It's apple juice. But let's go for it. Is it good? Is it good enough? All right, it's obviously good enough to drink. Would you like to drink some as well? OK. So that's very easy, isn't it?

Now let's imagine this is wine, and you've had a few more bottles. Let's see what the effects of alcohol could do to your coordination. Would you like to pop on these goggles? Sir, if I may. Are they tight enough for you? All right, now would you like to again have a glass of your wine?

[LAUGHTER]

OK, now that's the bottle. OK, have a little drink again. Maybe you'd like to say cheers and clink your glasses together.

[LAUGHTER]

I think you've both had a little bit too much to drink. Well done. Round of applause everyone.

[APPLAUSE]

Round of applause, thank you. Let's see if we can give the viewers at home and the audience what impression of wearing these goggles is really like. So I can see it there. You see, it's distorting everything, isn't it? And as you try to reach, you lose all your coordination. So the goggles is really producing a distortion of your vision. Thank you very much, David. It doesn't really make you drunk. It just creates what it's like to be drunk as far as your vision's concerned.

But alcohol doesn't just affect vision. It affects your movement. It affects your decision making. All of your coordination is disrupted by that. And that's why drinking, of course, is very dangerous if you're controlling a large machine like a car. Because your coordination and also your judgment is impaired.

Now we also know the frontal lobes are the last part of your brain to mature. And this explains why often very young children can be very uncoordinated and very impulsive in many ways. As teenagers you're currently also experiencing some of the most dramatic rewiring of your frontal lobes. So your control systems aren't yet fully up to speed. But don't worry. You guys are coming up to your prime. When you get to my age, it's all down hill from there. I'm afraid so. That is true.

So the frontal lobes are not just responsible for judgment and control, but they also allow you to see into the future or at least imagine what our future might be like. So let's see if any of you can tell the future. Because I have a tale of terror to tell. And I need to have a fortune teller.

[SOUND OF THUNDER]

And I want to take you to Zombie Island. OK, so prepare to be amazed. So we actually selected some volunteers earlier on. And here we have - hello, guys. How are you doing? So who's going to my research assistant? Your name is?

Liam.

Liam, you're going to be Igor for tonight, OK? And we have a zombie. And who are you?

Louise.

This is Louise, the zombie. And you're a typical child, aren't you?

Yep.

And what are you, typical child?

Jessica.

This is Jessica who is going to be our typical child. And you're a bar of chocolate. And who are you?

Alice.

Alice is our bar of chocolate. Now Igor, you're my trusty research assistant, aren't you? Now I need you to transport all the bars of chocolate and the children and the zombies to my laboratory, which is over on zombie island over there. So let's take all the items for my laboratory, and let's stand over there. You stand there.

[SOUND OF RAIN AND THUNDER]

Now what we have to do here, this is a real task. It's a real problem where Igor has to use his frontal lobes to figure out and solve the problem. Because the problem is Igor, you can only carry one person at a time or one zombie or one bar of chocolate over to my island. So you must transport it on the raft and get it over to there. But the problem is, of course, that you can't leave children with chocolate, because children always eat the chocolate. And you can't leave the zombie alone with the child, because what do zombies eat? Brains.

OK, so remember don't muck up. Don't leave them together if they're going to eat each other. You got it?

Yep.

OK, so let's see how Igor gets on. Because he's going to figure this problem out. Who are you going to bring over first of all on the raft?

The child.

Let's see you do it then. Pop him on the raft and we'll give you some help here. So are you thinking of the solution? Are you working it out in your heads? See if Igor is going to get it right. Here we go. So that's the right solution. Because you've left the zombie with the chocolate. Now Igor, what are you going to go and get for me next?

Chocolate.

Chocolate, OK. Now you see how he's working it out? He's thinking about how to solve the problem.

[THUNDER]

Very good. Now Igor, you've left something on the mainland. I need the rest. Can you go and get me my zombies?

Can I bring back the child?

OK, that seems a good idea. OK, on you pop safely down. Very good. Is he getting it right? Yeah? Very good. Come on Igor, what are you going to bring next?

A zombie.

A zombie. There we go. Well done, Igor. Of course, all you need left is - there we go - the child. I think it's a solution there. Big round of applause. Well done.

[APPLAUSE]

Let's come back with the zombie. There we go. OK, we can let you go. Thank you very much.

So what they were doing there is they were using their frontal lobes, because they had to anticipate the consequences of the actions. Now if a person with frontal lobe damage was trying to solve Zombie Island, they would muck up. And they would probably leave the wrong combination, because they can't anticipate what's going to happen next. It requires planning.

Now of course, planning becomes more difficult when you're doing more than one thing at the same time and especially if you're under time pressure. You need to be able to focus your attention on the task at hand. Because complicated tasks require coordination.

Now this coordination enables us to do more than one thing at the same time, such as texting your friends when watching television. So long as the different tasks do not compete for the same neural parts of your brain, then everything should be OK.

But what happens if they do? Can I get four volunteers for the next one? OK, let's get some people from the back here. Lady with the stripey top on the end there. OK, down you come. Chap there on the end there. Down you come. Let's choose someone from over here. Sir with the red top, down you come. And let's get someone, there with heart on your sleeve. There we go. Come on down. Well done. So who are you?

[APPLAUSE]

Let's find out who our guests are first of all.

Nick.

Nick.

Emma.

Emma.

Sam.

Sam.

Isabelle.

Isabelle. OK, why don't you all have a seat, please. Make yourself comfortable. Now this is a very simple test of control of your frontal lobes. I want you to just with your left leg, just lift it up and rotate it clockwise. OK, now you can try this at home everyone. Just rotate your legs clockwise. In big circles. Come on, let's see big circles clockwise. There we go. You got it all now? Very good. Very easy.

OK, now stop. Now with your left hand, I want you to draw the number six. OK, that's quite easy, isn't it? Now look what happens when we put two of these things together. Let's start off with your left leg clockwise. Everyone can have a go. Now draw the letter six.

[LAUGHTER]

It looks like it's all falling to pieces, isn't it? It's very, very hard. Yeah, how are you finding it? Very good. Round of applause for our guests.

[APPLAUSE]

Thank you very much, our volunteers. OK, we're really going to make this work. This is because this is called interference. And it's because different parts of the body when you're moving them, you're trying to coordinate them. And they're both trying to work with the same area.

So moving your leg in one direction interferes with moving your hands in the opposite direction. And you need your frontal lobes to be able to coordinate. It's hard to coordinate those movements. But hark, I think I hear a man who can.

[MULTIPLE INSTRUMENTS PLAYING]

[CLAPPING]

Hello, sir.

Hello. A big round of applause.

[APPLAUSE]

Let me introduce you to Jake Rodriguez, a one-man band. Now Jake, how long have you been playing this one-man band?

I did my first one-man band when I was about 18.

About 18.

Yes.

And how many instruments do you have now?

I've got two jingle bells.

Two jingle bells.

That foot's attached to the bass pedal. This one's attached to the cymbals on the top and the tambourine. So that's one, two, three, four, five. Banjo, harmonica, a couple of these. Oh, it's about eight, nine, ten. Round about that. Horns and things.

Eight, nine or ten instruments.

Yes.

OK, and now obviously, when you must've learned them, you didn't start off all of them at first, did you? Or do you pick them up one at a time?

Yes, especially the horn took a lot of work. That one to get that together.

And do you find that when you think about what you're doing, does it get a little bit complicated? Do you just go for the rhythm or, how do you do it?

Well, it's quite instinctive to do a walking rhythm. What's harder is to add a few more bits to it. And if you get yourself in a bit of a pickle, you've got to be playing at the same time and unpickling your head at the same time.

Right, I've got it.

But that's not hardest thing.

So the things which are automatic you don't have to think about. And that's like walking, so that's easy.

Yes.

And the things which need a lot of thought, that requires more of your frontal lobes working away. Is that right?

Yeah.

Let's give a big round of applause to Jake Rodriguez.

[APPLAUSE]

[MULTIPLE INSTRUMENTS PLAYING]

[LAUGHTER]

He wouldn't make a very good robber, would he? Anyway, the way Jake coordinated all these is through practice. He was using his frontal lobes. Now the things that didn't need a lot of thought, like the walking, he didn't have to really monitor. He didn't have to consciously control. And all the other things he had to really pay attention in order to make these work together.

So in fact, when he gets really good at this, he doesn't have to think about. Some activities are not under conscious control, such as breathing and walking. Other activities like doing your homework and sitting in front of the television, that requires the executives in your frontal lobes when you have to concentrate.

But in some cases, your brain has to block out information too. When you stop yourself doing something, you have to make a real effort, especially if the behavior is automatic. In other words, not doing something often requires you doing something. And that's what your frontal lobes are doing.

So let's see if all of you can stop doing a very automatic behavior using your frontal lobes and mental effort. For this test, I want you to turn to the person next to you, and I want you to try and stare at them, OK, without blinking. And I want you to take turns of trying to make them blink by simply poking their eyes. So we'll try this. OK, you try and stare, OK. And try and not stare. There we go.

[LAUGHTER AND CHATTER]

See if you can make him stare. OK. What you'll notice is that actually it's really quite hard to do. Now some of you are very good at doing this. And one of the reasons are typically if you're used to putting mascara on or anything near your eyes, then you don't have a problem. Or if you have contact lenses, you very often stick these near your eye.

But if you don't do this very often, then it's a very difficult thing to avoid. Because that blink is a reflex. That's the brain trying to protect your eyes from anything damaging them. And that requires conscious effort to try and stop it.

It's not just reflexes, if you think about it. The world is full of distractions. It's like being a kid in a candy store. There are just too many things trying to grab your attention. Now sometimes we need the ability to stop doing one thing in order to do something else. So the frontal lobe has to work out which bits of information to block out.

So let me try another test for you. This is something that's going to be a surprisingly difficult task. And again, you can try this at home. In this task I want you just to read the colour of the ink, OK? I don't want you to read the word. And I want you to do it as fast as you possibly can. So let's see if you're ready yet. Go.

Red.

Green Blue.

Green.

Red.

Blue.

Black.

Black. Very good. Very good. OK, that wasn't bad actually. So let's try that again. I'll try and go a bit faster.

Red.

Blue.

Red.

Green.

Green.

Blue.

Black.

Royal Institution crowd, very smart. OK, so you're really good at this, aren't you? OK, ready?

Blue.

Red.

Green.

Red.

Blue.

Green.

Black.

Well, I found it very hard. But you did very well, I must confess.

[APPLAUSE]

Give yourselves a round of applause. That's called a Stroop test. And what a Stroop test reveals is that reading is such an automatic behavior. When you're very good at it, you really don't think about it that much. So when you see the word written in one colour, your tendency is just to read the word, not say the colour of the ink, which is something you don't normally do. And if you have damage to your frontal lobe, it's very difficult to do the Stroop test, because it reveals that this part is controlling behaviors.

So our frontal lobes are important for vigilance and attention. Throughout evolution we've had to look out for danger. Now in the olden days, it was things like saber-toothed tigers. Today it's Jaguars traveling at 40 miles per hour up Mayfair. So avoiding danger requires attention. When not paying attention, you can easily miss things which are right in front of your very eyes.

So I'm going to show you a scene outside San Francisco. And I want you to watch this scene. Because does anyone notice anything different, what's happening here? Let's see. Does it look like the same scene to you each time it's flicking on? Put your hands up if you think it's the same scene. Yeah, some yes, no, yes. It's the same thing, isn't it? Or is it? Are you sure?

Well, let me show you what happens when I remove the blink. There we go. That's what's actually happening. You can see now that when I take the blink away, every frame has a different change. Things which you would never believe that you would ever miss. For example, there goes the tree. And then when I put the blank in, you can no longer see the changes. Look. Isn't that remarkable? And then I put it back in again. There they go.

So this is really a very strong proof that if you're not paying attention, you don't miss things which are happening right in front of your very eyes. This is called change blindness. Every time your visual world disappears in the blink of an eye, your brain doesn't notice anything different, unless you're paying special attention. So your brain is regulating our behavior, deciding what we should pay attention to, how we learn, and what we remember, all without us even realising.

Now we started this lecture with the question, who's in charge? And actually, I'm still not really sure. Is it my memory, my frontal lobes? Well, they all play an important part. But there is no individual me taking control.

So let's put everything together that we've learned tonight into one final demonstration. I began with juggling, not very good. But I'd like to introduce you to some really great jugglers, all the way from Croydon. Ladies and gentleman, Croydon Juggling Club.

[APPLAUSE]

[FESTIVE MUSIC]

[CLAPPING]

OK, so I'm going to get the audience to try out their frontal lobes here. Because I'm going to test them on a task of concentration. Because to juggle requires a lot of concentration, doesn't it?

Absolutely, yeah.

Can you show us a single juggle where you toss the orange batons? And I want you to count the number of times that they toss it, OK? So give us an example of this.

One, two, three, four, five, six. OK, can we stop there for a moment? So that's going to be the task for tonight. I want you to count the number of times the baton passes. Now I want to find the person who has the best memory, the best observation skills, the best vigilance, so keep the answer to yourself. Because at the same time, I'm going to get the back jugglers to juggle to confuse you.

And so as the orange baton crosses, I want you to count the number of times and then remember it. So pay special attention. OK, on your mark. You can start. And don't shout it out. Just keep the answer to yourself.

[FESTIVE MUSIC]

OK. Round of applause.

[APPLAUSE] So who thought that the answer was 24? Well, you're right. So 24, stand up. OK. So young lady, did you notice anything strange when you were counting there?

Did you notice anything strange, for example, about me?

Taking your jacket off.

Take my jacket off. Anything else about the stage? Skull, yeah. Did you notice that the skull had changed and the top hat didn't go on? No? Did everyone get the top hat going? And of course, did you notice this? Have a look at the video. Did you see the gorilla? Have a look.

[LAUGHTER]

Did anyone see the gorilla? All right, big round of applause.

[APPLAUSE]

Now, I know some of you know this demonstration. But hands up if you honestly didn't see the gorilla. I think that's a pretty dramatic demonstration that you don't always notice everything in the world. Thank you very much, Croydon Juggling Club.

[APPLAUSE]

When you focus your attention, it's difficult to miss everything. So we began by asking, who's in charge anyway? And we ended up questioning whether there's a single you inside your head in the first place. In the final lecture, we'll be exploring whether we are individuals or rather we're individuals born with a social brain to learn from each other and coexist in groups.

So thank you for watching so attentively. And it's good night from me. Or rather, it's good night from my frontal lobes. Good night from my hippocampus In fact, it's good night from my brain. Thank you.

[APPLAUSE]

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