Silent Messages Royal Institution Christmas Lectures

I use my mobile phone to send silent messages all the time.

But what if I could control someone else's face?

I'm sending quite a message there, aren't I?

That looked a bit surprised.

Now, our faces are extraordinarily powerful tools

for silent communication.

We can say a huge amount

without using any sound or any speech at all.

In this lecture, we're going to reveal

why silent messages are one of the

most powerful forms of communication on the planet,

and why, for many animals,

it can make the difference between life and death.

Welcome to the second of

the 2017 Royal Institution Christmas Lectures.

I'm Professor Sophie Scott.

Right now, I'm talking to you to get my message across with my voice.

But like you just saw with my colleague's twitching face,

not all communications are made with sounds.

We, like many other animals,

use our bodies to send silent messages

about who we are, how we feel,

what our intentions might really be.

In this lecture,

I'm going to give you an insight

into this world of silent communication,

and reveal how you can start to spot and decipher some of it.

I'm going to start with what is probably

the first way that any animals

worked out how to communicate.

That's using chemical messages.

We would call those smells.

I'm going to send your noses some information and you're going to know

when that information's coming towards you

because you'll see a smoke ring.

Anybody tell me what that smelt like?

There's something kind of sweet there, isn't there?

There is a sort of sweet smell.

I think it's supposed to be kind of like a

candyfloss kind of smell, OK?

That might suggest something edible,

something edible's going on.

Let's try a different smell.

Ha-ha.

You took a direct hit there.

What do you think about that smell?

Uh, poo.

Do you like it?

Yeah, it's great!

I quite like it,

it reminds me of home!

Now, that was, indeed, the smell of poo.

It's called skatole and it's a synthesised version of some of the

molecules in poo and probably if you were to smell that, you might think,

"I don't know if I do want to eat that food."

You know, it's contaminated, there's information there.

Now, slightly disturbingly,

all smells are made of something physical.

They are chemical molecules, they are literally parts of a thing,

a body or an object that have been released into the air,

and we detect those in our noses by chemical detectors.

Sending messages with chemicals like smells

is really a very basic form of communication.

And that's because everything,

from bacteria to blue whales, is made of chemicals.

So, the simplest way to send a message is

just leave some of those chemicals behind.

A chemical that an organism uses to communicate

with another member of the

same species is called a pheromone,

and this is any chemical that's released by one individual to affect

another individual's behaviour.

And amongst the animals,

the absolute champion users of pheromones are insects.

In fact, many insects rely

completely on using smells to communicate with each other.

To find out more,

please welcome an expert in how insects use pheromone messaging.

From Rothamsted Research, Dr Gia Aradottir.

-Hi.

-Hello, lovely to meet you.

Nice to meet you.

Now, if you could just step forward.

Can you show us, what have you got in your hand there?

So, here I have some aphids on a leaf.

-OK.

-They're very small, you won't be able to see them from there.

But if I put them under the microscope here, hopefully,

you can see them on the screen.

Yep.

Can you see these? So, these aphids are all mothers and daughters,

they're all female, all girls.

-Aphid power!

-Aphid power.

And they're happily feeding on the phloem on the leaf.

OK. So, we've got a group of aphids.

If they wanted to send an alarm signal,

if something was going wrong,

what would they do?

If one of them is attacked by a predator, like a ladybird,

for example, it will send a message, an alarm pheromone,

out into the air,

and that basically tells all of the other ones that they need to escape.

-Can we see that?

-Let's try.

So, I have here some aphid alarm pheromone in this little vial.

And if I put a tiny drop of alarm pheromone on the leaf next to the

aphids, then, hopefully...

Oh, they're off.

Can you see? They all move away

because they think that one of them is being attacked.

Can we smell that?

I can't. Let me put a little bit here on.

The aphids all ran away but we didn't!

No, I don't think I can smell that. This is one of the really

interesting things about smells, isn't it?

Because if you haven't got the

chemical receptors to detect a smell,

it's just not there, it's completely invisible to you.

You are blind to it.

So, this is a very private way of having a conversation.

It is. And it's happening in our gardens, in our parks,

and we have no idea what's going on.

But if some other animal could learn about that message,

could they start to intercept this information?

Yeah, nature is so clever.

So, predators have already learned

how to recognise the alarm pheromone of the aphid.

They are basically eavesdropping on

the communication between the aphids.

This alarm pheromone tells them that there is a prey there,

there's an aphid that they can go and eat, for example.

What kind of predator do we mean?

So, we have parasitic wasps,

and I've got some here in this little Petri dish.

Manage your anxiety, they're really small,

I don't think they'll go after us.

They're very, very small and they only go for aphids.

Let's see if we can find one.

So, the wasps are picking up on the communication between the aphids.

-They're listening in?

-They are.

To the signals from the pheromones?

Yes. Absolutely.

Is that an aphid? That's an aphid.

Oh, dear, is it at terrible risk?

It might be.

We can look.

-Oh.

-See?

Did you see that?

What was actually happening there?

I think it may actually have laid an egg inside the aphid.

-The wasp?

-The wasp.

Laid an egg inside the aphid?

Yeah. That's what they do. They search for aphids,

and they lay their eggs inside the aphid.

The egg then hatches, and the larva eats the aphid from the inside out.

So, to be absolutely clear, we just saw something absolutely terrifying?

-I think so.

-From the point of view of an aphid.

-Yeah, from the point of view of an aphid.

-But great if you're the wasp.

-That's amazing.

-That's fantastic. Yeah. Thank you very much, Gia.

Thank you so much.

So, how are these insects picking up on the chemical messages?

If you look at an aphid,

you can see it's got these large antler-like projections

coming out of the top of its head.

Those are its antennae.

They are amazing at picking up pheromones.

But how do they actually work?

If we were to zoom in to the surface of the antenna,

what we find is they're covered in these fine hairs, sensory hairs,

and the hairs are what is actually doing the smelling.

The hairs have got very small holes in them.

And these holes let molecules of air and other chemicals come through.

So, that's moving through all the time,

chemicals are moving in and moving out.

In the centre of the hair...

..there is a nerve cell.

And what the nerve cell wants to do is detect pheromones.

It's got the receptors for the pheromones.

But if stuff's just moving through the holes,

it doesn't make contact with this nerve cell.

What we need is another factor,

something to actually link it all together and that's called an

odour-binding protein.

And I need a volunteer to help me with this demonstration.

Ideally, I need an odour-binding protein,

but I will also accept a human!

Can I have you? Thank you very much.

You look like a very excellent odour-binding protein!

Thank you.

Now, what's your name?

-Shreya.

-Shreya?

-Yes.

-Now, Shreya, you're no longer Shreya,

you are my odour-binding protein.

And to convey this, you need to wear the odour-binding protein hat.

I'm sorry, it's just the rule for the odour-binding protein club,

come here, hat on.

Transformation, I think you'll agree.

And I need you to take

your odour-binding protein receptor and put that on

your right hand. There you go.

Now, that's what you're going to use to catch molecules.

But you can't catch all the chemicals.

You can only catch things that will work

with the odours you have the receptor for.

So, I'm going to try this.

Will you be able to catch this one?

No.

Oh. Excellent, mad skills, turn it upside down.

There we go. Now, you really can catch that.

So, what I want you to do is, they're going to start moving at

speed through these holes in the hair.

What I want you to do is catch them and, when you've caught one,

bring it over to the nerve cell and make a contact.

You also need to make a contact with your hand as well so you've

completely triggered the nerve cell.

And that's sending the message off to the aphid's brain.

When you've finished, just drop the ball in there, and you're done, OK?

Are you ready? We're going to see

how many of these pheromones you can

catch in the next 20 seconds.

I'm going to count you in.

Three, two, one.

There you go, there you go, other hand.

Good, brilliant. Pop it in there. Fantastic.

You can catch them on the floor. You can catch them on the floor.

-AUDIENCE:

-Five, four, three, two, one.

Well done!

Well done, Shreya.

Well done.

That was very good. You got one but I don't think I'd have caught any.

So, thank you very much. I'll have your...

I'll transform you back into a human.

So, what you did there was you were actually allowing the aphid to know

that there was an aphid alarm pheromone

in the environment by actually causing that nerve cell to fire.

So, your aphid has safely escaped

and you can all run out of the room now, if you wish to! There we go.

Thank you very much, Shreya, thank you.

You can think of pheromones as being a bit like hormones,

they're things that affect...

Chemicals that affect your body and your behaviour.

But unlike hormones,

it's a signal that's coming from outside of the body.

Insects live in this world where pheromones are extremely important.

But what about animals closer to us in the evolutionary tree?

Do they use pheromones as well?

Well, here is an animal that's not necessarily

absolutely everybody's favourite animal.

Snakes.

Now, Phil, I see that you've got two snakes.

I've got one. I need some volunteers.

I need a volunteer who's absolutely

not going to freak out when and if

they meet a snake. OK.

Can I have...

You there in the pink sweater? You there, yes.

And can I have you there in the Christmas sweater with the glasses?

Yeah, fantastic.

I don't see why I should be the only person freaking out because they've

got a snake going down their blouse.

Right, OK. So, what's your name?

Have your hand up like that...

-Obiay.

-Obiay? Hello, Obiay. And so, what's your name?

-Gia.

-Gia. Now, Gia.

-Well done.

-Oh, thank you.

Can you see these snakes are sticking their tongues out a lot?

That's because this is an unfamiliar environment for these snakes and

they're exploring it, they're exploring it with their tongues.

The really interesting part about these tongues

is that they themselves don't have any receptors on them.

They haven't got taste buds on, like our tongues.

What the snakes are doing,

they're capturing molecules from the air and they're bringing them into

the snakes' mouths. Now, this is different from the snake's nose.

You can see they've got nostrils up at the top of their face.

The organ that they've got inside their mouths

is called a vomeronasal organ.

And it actually lives...

..on the roof of the snake's mouth.

So, they bring the tongue in,

and they dip the two tips of the tongue into each side,

there's actually two little holes for the vomeronasal organ,

and that's making direct contact with pheromones into nerve cells.

So, that information can pass straight up into the snake's brain.

There's a fork in the snake's tongue and that means they can tell if the

smells have come from the left or the right.

So, it's able to move in the direction

that the pheromone has come from.

What's all this for?

Well, mostly, for snakes, it's about finding a mate.

Snakes are shy creatures that hide and ambush their prey.

And this system means that the male snakes can detect pheromone messages

being given out by a receptive female snake from a great distance.

Good news for any lady snakes in here this evening.

So, I'm going to say bye-bye to our highly friendly snakes.

That's fine, you guys, well done.

-Well done.

-Obiay, fantastic.

Gia, very brave.

-Well done.

-Fantastic, thank you.

They did brilliantly.

I was freaking out, I don't know if you could tell that.

So, what other animals also have a vomeronasal organ?

Well, it turns out quite a lot of them do.

A lot of other mammals have got vomeronasal organs that they use for

smelling pheromones.

So, if you've ever looked at dogs

smelling other dogs' bottoms and thought,

"I fail to see the appeal of that,"

well, actually, it's because the dogs are smelling pheromones.

And they are very short-lived pheromones,

so they can't pass off into the air,

so the dog's really got to put its nose

into its friend's bottom to get to those pheromones.

Probably too much information there!

When cats pull a funny face,

if a cat's ever got on your lap and gone...

..that's the cat trying to smell your pheromones.

Now, I love cats.

I don't know if I absolutely want them smelling what they might think

might be my pheromones, but it's what they do.

It's because it matters so much to mammals.

They live in a world of smell.

Do humans - we're mammals - do we have a vomeronasal organ?

Can we use smell to send messages?

Well, if we look at the roof of a human mouth...

..what you find is no evidence of a vomeronasal organ.

We don't seem to have the receptors

to actually pick up pheromone information.

Now, we like smells, don't we?

We do. We pay attention to smells,

you cared about the smells we sent

around the lecture theatre earlier in the evening,

but they are less important to us than they are to other animals.

For other mammals, smell dominates.

It can be the most important sense.

Why might we have lost some of our ancestors' smelling abilities,

and along with it maybe our ability to use pheromones?

Well, to think about that, we need to think about how primates evolved.

These are three primate skulls.

We look here, this is an ancient primate, this is a lemur.

That's an ancestral ape, so that's one of the ancestors of apes.

And this is a modern human.

And one of the things you can notice

as you get to humans is that faces...

..start to get much flatter.

We just have smaller noses.

We've got less space for there to be smell information detected.

Smell is just downplayed right from the start in humans.

And you can also see that there have been other changes.

So, for example, our faces are longer, our mouths are taller,

there's more space inside our mouths,

and we have much bigger eyes.

And, in fact, if you look in the brain, you see a similar pattern.

A lot of other mammals have got huge amounts

of their brain devoted to dealing with smell.

In humans, those smell areas are very small.

And, in contrast, in humans,

the brain areas associated with processing

sound and vision are much larger.

So, what we've done is we've really

traded off the space in our faces and in

our skulls for dealing with smell information,

and we've replaced it with vision and hearing.

And that's probably because...

..vision and hearing have great advantages for humans,

not least for communication.

Now, no disrespect to smell, smell works really well for communication.

At a distance, for example, smell can be great.

You saw that with the snakes.

But smells will only move at the speed of the air around them,

and they can linger a long while.

I am sure the aphids would prefer

that the wasps couldn't pick up on their

distant alarm pheromone messages.

If, however, you want to send faster, more complicated messages,

you need a speedier system.

So, let's look at a more flexible way to communicate.

Let there be light.

Many animals produce their own light.

This helix of light is made in a

very similar way by mixing together two chemicals.

In the natural world,

a chemical called luciferin is

mixed with an enzyme called luciferase.

The reaction causes light to be given off.

-AUDIENCE:

-Ooh!

Making light via this kind of chemical reaction

is actually one of the

commonest methods of communication on Earth.

It's called bioluminescence, and deep sea fish are famous for it.

To explain more, please welcome from the Natural History Museum,

curator of fish, James Maclaine!

Hello, James. Nice to meet you.

Now, if you could just tell me

what you've brought along for us today?

I've brought along a tiny fraction of our huge deep sea fish collection

that we have at the Natural History Museum.

So, in our first jar we have two specimens of a thing

called a Threadthin dragonfish.

So it has a light organ

on a little barb underneath its chin,

and it uses that to attract its prey towards its mouth.

And then all along its tummy it has rows and rows

of little lights there.

And what that's for is actually for camouflaging itself,

so during the day when there is still a very faint amount of light

above, it makes its underside glow very faint blue,

so that if you look up, you can't see it.

And then, my favourite thing about them,

is they have a light organ behind their eye,

and in the male it's much,

much bigger than in the female.

So what we think is, it's like

a sort of deep sea version of a peacock's tail.

It's a display thing, so it gets her attention.

Fantastic. What about these guys?

They are called Lanternfish,

and they have a very distinctive pattern of lights along their sides.

It's a bit like a constellation of stars.

It's very distinctive. And it's so

distinctive that's what they use to recognise each other.

They live in big shoals,

so that's how they work out they are

-in a shoal of the same Lanternfish as themselves.

-Amazing.

-What about this guy?

-This one is quite interesting.

This is a stoplight loosejaw.

And everything I've mentioned so far is using blue light,

but this uses blue lights and red lights.

Why do they use blue lights?

Blue light travels the furthest.

It's the frequency of light that penetrates the furthest,

so if you want to get your signal out there, blue light is

the best light colour to use.

-OK.

-But this

can also create red light.

It has, like, a light organ just

underneath its eye, but points forward, like a torch beam.

It can hunt out little animals using its red light,

and nothing else can see it, because

everything is tuned to the blue light.

And, finally, what do we have here?

I think this is my favourite.

I like it so much, I'm going to get it out for you.

There is actually two fish in here. This is a deep sea anglerfish.

The males and the females are very different.

The males have become very, very small.

They are now so small and pathetic that they can't actually survive by

themselves, they have to attach themselves to the female,

and feed off her, like a little vampire.

So, if I hold this very still...

That little, sort of, tadpole thing there, is the male.

And he's actually like a little parasite.

Very judgmental terms here, James.

He's been a vampire, a parasite, and pathetic.

He is a little bit! She's using light,

so she has, like the dragonfish,

she's using light for catching her food.

So that little matchstick-like thing there would be going,

that little blue dot. That's what she uses to lure her prey in.

And this lovely beard that she has,

these have light organs down there, too.

We're not sure what they are used for.

They may even be, sort of, like, landing lights,

to guide the male in. We just don't know.

Thank you very, very much. There's one more thing I needed to ask.

They are making light, how are they actually doing it?

Well, these three are doing it in a very, sort of, chemical manner.

They have two chemicals, I think

we've mentioned them already, luciferin and luciferase.

They combine the two, and that turns the light on, basically.

-Like glow sticks.

-Exactly, yes.

But the angler fish is doing it in a much more clever way.

It's actually getting someone else to make the light for it.

She acquires, as she grows, little luminescent bacteria,

and she keeps them,

cultures them, and grows them,

and that's what she uses to make her lights.

Amazing. Thank you very much, James Maclaine, thank you.

I won't shake your hand!

Now, fish are not the only animals that communicate with light.

It's a technique used by jellyfish and squid,

but also above the water by insects like fireflies.

Now, this firefly is using light to attract females.

What is quite interesting about some species of fireflies

is that, in groups,

they start to synchronise their flashes somewhat,

with each other.

Why would they do this?

Why would there be value in flashing your light at the same time as the

other males that you're competing with to attract females?

Well, we're going to have a look at a demonstration.

You're all wearing LED wrist bands.

Can you hold them up next to your head? Fantastic.

And they are going to get turned on.

What we're doing here...

On this screen we've got a camera set up

that's picking up those flashes.

So you can see is something going on in the auditorium

with these random flashes.

If we start to make your wristbands

start to flash more in synchrony with each other,

you start to see something a bit more

coherent appearing on the screen.

It's more salient. It's more noticeable.

When you synchronise your flashes...

..with the other fireflies around you,

what you get is a signal which is much stronger.

And that, potentially, might be more noticeable by the female.

You've still got to compete with those

other males once you've attracted the females,

but maybe you'd be more likely to attract

more females in the first place, if you can be seen.

It's also the case that different species can use different kinds of

flashing sequences to signal what species they are.

Maybe that's also helping the females know

who they are looking for.

Interestingly, in a very similar way,

different UK lighthouses flash lights with different patterns,

so this tells ship captains not only that there is a lighthouse there,

but also which lighthouse it is.

And, interestingly,

that's a technique that was brought to the UK by

Michael Faraday, the man, and the scientist,

who started these lectures here at the Royal Institution.

So we've seen animals that make their own light to communicate,

but daytime land dwellers like us don't need to do that,

because we've got a great big light in the sky.

We've got the sun.

And the sun is making light.

Out in that daylight,

we can be seen.

We can take advantage of the fact that we are visible.

And we can use this to communicate

our state of mind, and our wellbeing.

We can change our body's position,

and how it moves, to convey that.

This is called body language.

And we are not the only animals that use it.

Please welcome Betty and Lola, and their owners, Dani and Martin.

Hello. Hello.

Aren't you lovely? Aren't you lovely?

Now, can I have a volunteer who

might like to come and say hello to a dog?

That's a popular one, that is.

It's going to be very difficult to choose.

I think I'm going to have to ask, can I have you,

on the end? With the white T-shirt, the grey T-shirt.

No, that's it, you're looking behind you.

Thank you very much. Thank you.

Now, very, very gently come and say hello to these good girls.

Hello. There we go.

Now, what does it mean when Betty wags her tail like that?

-AUDIENCE MEMBER:

-It means that she's happy.

She's happy, and having a good time, yes, exactly.

We all know this, don't we? A dog wags its tail when it's happy.

Well, the situation turns out to be a lot more nuanced than that.

Scientists from Genoa University

have recently suggested that dogs

will wag their tails slightly differently,

depending on their mood.

What they found is the dog with the

more left-leaning wag is a rather more

calm, relaxed, happy dog.

Whereas a more right-leaning wag

means the dog's a little bit more anxious.

You can see this on the clip here.

That's a more rightwards wag,

slightly more anxious dog.

And here we've got a leftwards wag.

OK. The really interesting part was,

they would show these videos to other dogs.

And the dogs watching these videos

would start to show slightly different emotional responses.

The dogs who are watching the more rightwards leaning wag

showed signs of becoming more anxious.

And the dogs who watched the leftwards leaning wag

became more relaxed.

So dogs really do seem to be sending quite a complex,

quite a nuanced piece of information in addition to just, "I'm happy."

Thank you very much for helping us with the dogs.

Thank you very, very much, Lola, thank you, Betty.

Thank you, Dani. Thank you, Martin. Thank you.

So dogs seem to be really good at reading each other's body language.

But can dogs pick up on body language messages

from another animal?

Like us? Many people will have noticed

their dogs behaving differently,

depending on whether they are in a good or bad mood.

But do those dogs really know what we're thinking?

At the University of Lincoln,

Professor Daniel Mills is testing whether or not

dogs can use our facial expressions to help understand our emotions.

Hiya. So these are some of the team that we've been working with.

These are just pet dogs,

they've not been specially trained for anything to do with the study.

We just want to see how they respond to

what's going on emotionally, around them.

So we want them to have

the full repertoire of emotional reactions,

lunging at cameras, and everything. OK?

What we have is, we have a set-up here, you can see these two screens.

And one of them shows an angry face, one of them shows a happy face.

The dog sits down here, and then we'll play them a sound,

and that will either be an angry or a happy sound.

The language is Portuguese, and Ralph here doesn't know Portuguese.

If they can understand emotion,

then the only thing linking the

sounds and the pictures is their emotional content.

PORTUGUESE SPOKEN WITH HAPPY INTONATION

PORTUGUESE SPOKEN WITH ANGRY INTONATION

What we find is that, actually,

the dogs spend more time looking at the picture that matches the sound.

HAPPY PORTUGUESE

HAPPY PORTUGUESE REPEATED

The only way you can actually do that is

if you can extract the emotional information from both.

ANGRY PORTUGUESE

ANGRY PORTUGUESE REPEATED

Sure enough, the dogs do this

integration of the different emotional signals.

They clearly have this much higher understanding of emotion than

we've previously actually thought.

ANGRY PORTUGUESE

ANGRY PORTUGUESE REPEATED

ANGRY PORTUGUESE REPEATED

So pet dogs really do seem to be

able to detect when there's emotional

information from the face and from the voice, they are coherent,

they are consistent with one another.

So they are definitely using our facial information to work out what

emotion we're expressing.

But how good are we humans at

picking up silent visual communication?

What do you think we are looking at here,

if our pile of ping-pong balls starts to move?

-Do you think we are looking at humans? AUDIENCE:

-Yes.

Yeah, OK. How many humans?

-Two.

-Do you think it's two men, two women?

-Two men.

-A man and a woman?

It's a man and a woman, I think.

OK. Shall we try some emotions? Give us an emotion.

-Scared.

-Scared. Perfect.

-OK, try another one.

-Angry.

Fantastic.

And one last one.

Happy.

Yes, fantastic.

Laughter, yes.

Fantastic.

Now, this is Blair and Alexis, and in fact,

you were getting all that information

from who they were and how they were moving

just from 14 points which

are marked on their joints for each of them.

So this is showing you how good you are

at pulling out information about how humans move,

because even with this really reduced amount of information,

you could tell a lot about who they were,

what emotions they were feeling.

Thank you, Blair, thank you, Alexis.

Now, our bodies give away a huge amount about our inner feelings,

but our faces can be even more expressive.

I've got a very scary video

that I want you to watch.

Please bear in mind, it is very scary,

but I need you to keep looking, OK?

I want you to watch this video and count how many birds you can see.

I will be testing you.

CALM JINGLY MUSIC

SCREAMING

I've got to tell you, that was a trick. There were no birds.

OK, don't worry if you hadn't seen any birds.

I just wanted you to get scared by the video.

Let's have a look at what we filmed, from you, in the audience,

and see if we've got any good reactions.

Oh, fantastic.

Now, I think that was you.

Did you feel scared? You moved right back, didn't you?

One of the things that's quite interesting, quite striking,

about these sorts of fearful facial emotions,

is that everybody's slightly different.

We're not all doing everything exactly the same way.

But you see these commonalities, for emotions like fear,

if we look back at your disgusted faces

when we were sending that poo-y smell out.

You could see some similarities there.

That's because these are examples of

what are known as universal, or basic emotions.

They mean the same thing wherever you go.

Now, it's not all our emotions, it's things like fear, anger,

and disgust, laughter,

and they are almost like a map of human emotions

that we can use to convey

how we're feeling for a certain set of emotions

that it seems all humans can experience and recognise.

But where do these emotional expressions come from?

Well, the fact that some of them are universal,

you find them across all human cultures,

is a hint that they come from deeper in our evolutionary story.

Hello, Charlotte. Now, this is a book,

a very special book from the RI library.

And it's a book by Charles Darwin.

Now, Charles Darwin is obviously very famous

for The Origin Of Species but

he also wrote this absolutely beautiful book

called On The Expression Of Emotions In Man And Animals.

Now, Charlotte, you are the archivist here

at the Royal Institution, yeah?

Can we have a look at some of the pictures here?

So this is examples that Charles Darwin

was giving of fearful faces.

Has he got a fearful animal in there?

So that's a fearful cat, the cat doesn't look exactly like the human,

the faces are different, but you are getting the open mouth,

he was trying to tease out how this could be working.

Maybe emotions have the same function,

in humans and other animals.

Maybe that's why they are evolutionarily important.

Thank you very much, Charlotte.

And, actually, the work that Darwin started has been

very influential over the next 150 or so years.

Many of his ideas about these motions we share,

across humans and other animals,

that have this ancient evolutionary basis, really have been borne out.

One idea about why they might look the way they do could be simply that

they've evolved to be as distinct as possible.

If I look frightened, you should be

able to recognise that unambiguously,

because if I'm frightened, you should be frightened, too.

So these basic emotions, they can't be uncertain,

they can't be too ambiguous.

You need to be able to pick up on them quickly.

So maybe that's why they look the way they do.

But what about when we don't want to give away our emotions?

A lot of the time, we work quite hard to cover up what we're feeling.

Sometimes because it might be a bit difficult for the social situation,

sometimes because some emotions are considered, in certain cultures,

to be simply inappropriate.

Right now, in our culture, we like to think that boys don't cry.

Boys, you're absolutely allowed to cry,

but we just believe it's not a very manly thing to do.

That's just us.

But it means that people often are

trying to put a face out to the world,

that might cover up the emotions they are really feeling.

And what I'd like to do is do an experiment with you three

to see if we can find out which of you is good at doing this.

Now, to do this what I have are three delicious sweets.

And I would like you each to choose a delicious sweet.

Don't put it in your mouth just yet, take the tissue as well.

Now, before you put them in your mouths, I have to tell you,

one of these delicious sweets is not even slightly delicious.

It's absolutely horrible. What we are going to do -

I don't know which one's got it -

we're going to ask you to put those in your mouths in just a second,

and we're all going to look at you

and see if we can work out which one of you has got the horrible sweet.

So your job is to try and pretend that you're absolutely fine,

you've got a delicious one. OK? We good?

Are we going to count them down? Three, two,

one.

I'm getting something here as well.

Oh.

Now, who thinks this person has the horrible sweet?

Who thinks you've got a horrible sweet?

Who thinks you've got the horrible sweet?

Actually, they've all got horrible sweets, I'm a liar, OK.

They are all horrible sweets. You can spit them out if you want to.

Apparently, if you keep going they become acceptable.

But...you don't have to.

The point here is that even though they were trying very, very hard,

everybody thought they were the only one with a horrible sweet.

But little bits of it were coming through.

We leak through our real feelings all the time,

even if we're trying to control what we look like.

And, of course, that can mean, in reality,

it can be quite complex to work out what someone's face is saying.

There can be a lot of things that they want to express,

and that they are trying to hide, on their face, all at the same time.

What does that mean for people who might encounter challenges when they

are trying to understand other people's emotions?

All this complexity in what faces say

can create real issues for people on the autism spectrum -

real issues recognising what other

people's emotions mean, and, of course,

what their own emotions might be conveying.

I'd like to introduce a robot who is a potential way to help.

Please welcome Zeno the robot

and Dr Alyssa Alcorn from UCL,

part of the DE-ENIGMA project.

Hello, Zeno.

Hey.

Alyssa, how is Zeno going to help?

On the DE-ENIGMA project we're using the Zeno robots as teachers,

as part of a programme working with children on the autism spectrum,

to help them learn about facial expressions

and tell different facial expressions apart,

what they are called, what they mean.

And this will help them in their everyday social interaction.

Fantastic.

Can we find out more about how he works,

or is it easier to do that with a volunteer?

-I think it is, actually.

-OK, now, I'd like you...

You can put your hands down.

Just pull your angriest face,

and I'm going to try and find a very good actor.

A really angry face.

Very, very angry faces.

There is a fantastic angry face there, with antlers, can I have you,

angry man? Thank you very much.

Now, just stand there.

-Can you tell me your name?

-Addy.

Addy? Fantastic.

Can you just come and sit here?

What we are going to ask you to do

is pull some emotional faces at Zeno.

And we're going to see - look on the screen here -

we'll see how Zeno is seeing that face. Is that right?

So, let's have a look up here.

And we see we've got this green box that appears over his face,

and it's tracking 49 different points on his face,

each little red dot there.

And if you start moving your face for Zeno...

See, the picture is moving, too.

And it's tracking those points, where they are,

how they are moving over time,

and then is using a machine learning process, using statistics,

to estimate what kind of face it thinks he's showing.

So if we look down here, right now, it thinks he's smiling.

I think that looks like a pretty good smile.

-That's a great smile.

-Yeah.

Shall we try a different expression?

Could you look frightened for us,

could you pull a screaming face?

So what's happening now is it's taking all those points there,

and using them like instructions for the robot's face.

It's telling him how to move the motors in his face,

so he's making the same expression, at almost the same time.

Fantastic, fantastic.

Can we try the smile again, then?

Turn your face back up. There we go. That's more like it.

Zeno is smiling, too.

You have an officially intense smile, that's quite impressive.

Thank you very much.

-Thank you, Alyssa.

-Thank you.

Thank you, Addy. Thank you.

It's really exciting to see how these modern-day robotics could be

possibly used to really help people who are struggling to understand the

nuances of facial expressions.

We've seen how amazingly complex facial expressions

can be on their own in humans,

but there's another part of our face

that communicates even more - our eyes.

In contrast to other mammals, humans have got very, very different eyes.

Our eyes are the same structure,

we've got the whites of the eyes, a pupil, and the iris.

But in all other mammals you can only see the iris and the pupil.

In human eyes you can absolutely

always see the whites of the eyes around that.

You are seeing the sclera.

And that seems to do two things.

It makes the eyes really stand out, our eyes are very high contrast,

very visible things.

And also, it lets us be very, very sensitive

to where exactly someone is looking.

And we use that all the time when we're having communication,

when we're talking to each other.

So if I just do a quick demonstration here,

I'm going to look down this camera.

And I'm going to tell you when I move my eyes,

and I want you to tell me if I'm looking directly at you,

or if I'm looking away.

OK. I'll start with my eyes closed,

and I'll try and move them every time I open my eyes.

OK.

At you or away?

At me.

Away.

Now, you're picking really, really tiny movements of my eyes up there.

I was actually moving my eyes only just to the side of the camera.

About two degrees of the whole visual scene around me.

So a minuscule amount.

We are incredibly sensitive to this, and what we do with that

is we use a lot of information about who someone is talking to,

what they are talking about,

and who they are talking about.

And we use it all the time.

Now, thanks for this,

I just want to ask you, do you think,

if I throw this sweet in the air...

..I'll be able to catch it?

I'm very good at this. OK.

Let's try this.

That wasn't very satisfactory, was it? Let's try again.

OK. That's better. Let's try a higher one.

OK. Now, can you throw this to me?

Oh, thank you. Now, can you throw it to me?

Mate, stop it, thank you.

Now, obviously, there were no sweets there whatsoever.

It was just a trick.

What I was doing was looking at where there was nothing,

and I was pointing at where there was nothing,

and I was pretending to hold nothing,

and we all just start looking at nothing

and pretending that I am throwing something in the air

and catching it in my bag. This is the same thing that we're using

when we use eye gaze in conversation

for kind of capturing attention.

We are focusing attention on who we are talking to,

who we are talking about.

For a long time, it was thought this kind of joint attention

was something that only humans could do.

It's turned out other animals can do this, too.

Dogs understand what pointing means.

And even, it turns out, some birds

can understand what eye gaze means.

Ravens are one of the few animals that seem to understand this.

They understand what it means when something is looking.

And I'd like you to give a not too loud clap

to a very fantastic raven called Bran,

and his owner, Lloyd Buck.

Hello. Hello, Lloyd.

Hello.

Hello, Bran. Now, Lloyd,

do you get the feeling that Bran uses information about where you're

-looking?

-Yes, very much so.

-Can we see an example of that, Lloyd?

We certainly can. Now, Bran has a special stone, he knows that word.

And it's hidden somewhere in this room.

So if I let him eat that piece of food,

then I'll say, where's your stone, Bran? Where is it?

And he's looking, and then if I look, where's your stone, Bran?

He did. He was really looking.

He looked around, and then looked where you were looking.

There's your stone.

Now, Bran. That's a good boy. Thank you very much.

Luckily, Bran chose the person in

the room we know is most easily scared.

Are you going to be OK?

That's amazing. But why would ravens be particularly good at this ability

to understand what it means when something is looking somewhere?

Well, it could be because it's very

useful as a way of helping them solve problems.

These are birds that have

to solve a lot of problems in the wild, aren't they?

Before we actually go into an example of this,

we're just going to show you how good Bran is at solving problems.

And we've got here a puzzle box Bran hasn't seen before.

It's got some food in it that Bran is going to want.

And what we are going to do is show it to him,

and he's going to work out how to

solve the problem of getting through to the stuff he wants in the middle.

-Is that OK? Are we all right to begin?

-Yeah, we certainly are.

Go on, then, Bran.

He's got to work out how to get into that...

Unbelievable.

That's it.

I've made it hard for him, this is not an easy one.

He just gave us a right look, like, "Oh, come on!"

Wow.

So he's got to pull the string.

-Yeah.

-This is an emotional roller-coaster.

-He'll get it.

-There we go, fantastic, well done.

Well done, Bran.

Now, in the wild,

a bird like Bran has got to solve puzzles and problems all the time.

And one of them is there are lots of birds like Bran out there

who are also very clever, so when Bran wants to hide his food,

he has got to find some way of tricking other birds

if they are looking at him.

Now, I've got a clip of a bird doing some deception,

a bird using communication to lie to other birds.

But Bran really dislikes videos.

So we're going to say thank you to Lloyd,

and thank you to the extremely clever Bran before we show that.

Thank you.

This is a bird that is being watched by other birds,

who all saw her bury her food earlier.

Now she knows they are no longer watching,

she's hiding the food elsewhere.

This is typical of raven and crow behaviour.

So, this is an example of ravens

using their understanding of eye gaze to

help them solve the problem,

of how they stop other ravens from stealing all their food.

And it's an interesting point,

that what you're seeing is them using deception

as a way of covering up what they really want to do.

But, of course, deception is still a form of communication.

So we've seen how much we can communicate

with our bodies and our faces,

even if we choose not to, or were trying to fake it.

There is a very basic communication

we do all the time that we're normally a lot less aware of.

And this is how we communicate a lot of friendship and affection,

and affiliation with other people,

by picking up little bits of behaviour,

falling into the same things that they are doing.

A lot of the time, we often do this

without even noticing we're doing it.

A few days ago we filmed two of you going for a walk together.

Are you here? We filmed you walking.

We've got a short clip of this here.

Notice what they are already doing.

They are walking in step with each other.

When you walk alongside somebody else,

you more often than not walk at the same rate as they walk,

even if they are a very different height from you.

And that's an example of this kind of

picking up other people's behaviour.

Just falling in with what they are doing,

without even realising that you're doing it.

You're doing a basic, friendly thing.

Now, you just very politely clapped along with me then.

I had no reason to clap, their walking was good,

it wasn't quite clap, was it? Now, what you are doing is,

you started clapping because I started clapping.

Another example of this, joining in, this, kind of, contagious behaviour.

Studies have shown people in

audiences are much more likely to clap if

somebody near them starts clapping, than if they don't.

It just spreads through the audience, like we just did then.

And, in fact, this kind of contagious behaviour,

where you join in with what other people are doing,

is extremely common.

Laughter, which I study, for example, is highly contagious.

In fact, you are primed to laugh,

just by other people being around you.

You're 13 times more likely to laugh

if there is somebody else with you,

than if you are on your own.

And these contagious behaviours

are still a very important form of communication.

Why does it happen?

What triggers it? Well, this is a picture from a recent study...

..that we did at UCL.

This is showing the brain networks activated

in teenage boys when they listened to laughter.

What we are seeing is a couple of different networks

actually being driven by listening to laughter.

These areas here...

..those are auditory parts of the brain.

And what they are doing is they are

processing the sound of the laughter.

These areas here...

..up there, and down there,

those are brain areas associated with producing movements.

What we are actually seeing here is when you listen to laughter,

even if you're having your brain scanned,

which is not remotely funny,

you are getting ready to join in.

Why on Earth would it be a useful form of communication

to just join in with what somebody else is doing?

Well, it's probably because we are social animals.

We rely on other members of our group for survival.

Picking up little bits of other

people's behaviour and joining in with them,

or reflecting back to them,

is a really quick and efficient communication that you know someone.

You like someone.

And this form of communication, by joint action, may, in fact,

be one of the most important things we ever do.

So we've seen how we can get across our thoughts, feelings,

our intentions, without necessarily ever uttering a word.

But all these forms of communication involve us using our senses to pick

up the messages - we are smelling things, we are seeing things -

could there be a possible future of silent communication

where we just communicate directly, brain to brain?

Well, 40 years ago, someone at NASA definitely thought so.

It's 40 years now since the two Voyager space probes left the Earth.

They each carry a Golden Record.

A bit like this. And there's a sound on the Golden Records,

that not many people know about.

LOW GRINDING HUM

Now, those are electrical signals from someone's brain.

And they've been converted into a sound that we can hear.

The idea behind including these on the record was that an alien species

might be able to read the thoughts that lie behind those brainwaves.

Now, reading brainwaves sounds like science fiction.

How far off the mark were they 40 years ago?

Well, Dr Ioannis Zoulias

and his colleagues from the University of Reading

have devised an experiment to see

if we can prove whether or not this is at all possible.

We've pre-selected a volunteer, Hannah,

to be the person who's going to send us a message from her brain.

She's sitting at the other end of the RI building.

She's wearing a headset,

and that headset is measuring, detecting and measuring,

the electrical activity inside her brain.

On the screen in front of her are two squares.

One is yellow, one's red.

And we're going to tell Hannah which one to look at,

and we're going to read from her brainwaves,

and try and decode that information.

Hannah's mother, Rashima, is going to receive this message.

Now, Rashima, you've got electrodes on your arms, haven't you?

So that suggests you might be

receiving that information via painful electrical shock.

And we're also going to need you to wear this blindfold,

so we definitely know that you can

only be getting the information through the signals to your arms.

And you're going to press one of these two buttons,

depending on if it's your left

or your right arm that is getting the signal.

-Sure.

-OK.

We've been testing this all day,

we've got nine results now,

and we're going to run the tenth

and final trial here.

For this last trial I need a

volunteer to select a message that we're going to send to Hannah.

Yellow or red?

OK. Can I ask you?

Just pick one of those.

Don't open it. This is the one you picked, get rid of that one.

Thank you.

Now, I'm going to give this to Natalie,

she's going to run this down to Hannah,

and she's going to show it to Hannah,

and we don't know what this says.

So what the computer is going to do is try and decode the activity in

Hannah's brain, and send this to Rashima's arms.

OK. Natalie,

can I just give you this? Have a very quick look.

Thank you very much.

When Hannah gets the paper she'll look at the chosen colour,

and the computer will interpret her brainwaves

and stimulate either Rashima's right or left arm.

There is Hannah.

OK, so Hannah is going to look at the screen,

she's looking at one of those two squares.

Which button is it going to be?

Red. Amazing, it's right.

Fantastic.

That makes ten out of ten successful trials we've run today.

And I think that definitely deserves a very big finish.

So what we're going to do is blow some stuff up.

This is going to be some noise.

Count me down, three, two, one...

I love the smell of burning balloons.

It smells like science!

Now, this is just a teeny,

tiny step towards the idea of being

able to send information directly from brain to brain.

We are nowhere near being able to communicate complex

thoughts via an electrical signal.

The average adult, for example, knows 35,000 words.

You would need a lot of electrodes

to be able to know which one of those that person was thinking of.

But every science has to start somewhere.

And maybe NASA weren't that far off

the mark with their recording for the aliens.

What I hope I've shown in this lecture is that we

and other animals already

communicate vast amounts of information in a

huge variety of ways,

without ever opening our mouths.

Now, we humans, we might not be using smells to communicate,

but we've replaced that with

an incredible ability to exchange messages with our bodies,

our faces, and our eyes.

If you can't pick up on this world of silent signals and hidden codes,

then you are definitely not getting the full story.

Thank you.