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00:00DENNIS SIGNS IS A VIETNAM VETERAN.
00:14EVERY DAY IS A BATTLE WITH HIS EMOTIONS.
00:19My concentration is lousy, my emotions are, I try not to get too close to people, including
00:27my wife and family, because to open up to them is, I find, destructive.
00:35The hopelessness, the death, death I, if I, you know, today I die, so what, you know?
00:51How can the terror he experienced in Vietnam have had such long-lasting effects on his
00:56brain?
00:57I don't know, I don't know, I don't know, I don't know, I don't know, I don't know, I
01:26don't know.
01:36Emotions are what make life worth living.
01:40They're indescribable experiences.
01:51Emotions come and go inside our heads, but moments of intense emotion take us over completely.
02:01They seem to involve far more than just thinking.
02:19We experience emotions with our whole bodies, the clenching of the muscles with excitement,
02:24the beating of the heart with joy, and above all, the utter sensuality of relaxation, the
02:30sand between your toes, and the sun on your face, and the wind in your hair.
02:39The search for things that feel good motivates everything we do, from playing with the children
02:45to going on holiday.
02:51But unlike most animals, we humans can take our time getting our emotional rewards.
03:02The interesting thing about us is that we don't live from moment to moment.
03:06We don't expect instant pleasure.
03:08Instead, we plan complex, long-term strategies that defer gratification.
03:13We're prepared to work hard for most of the year to save money for two weeks of bliss
03:17in the sun.
03:22Unraveling how our brains create emotions is an awesome challenge.
03:31Why do they feel the way they do?
03:34And how are they interwoven with our thought processes?
03:43As brain science unlocks the secrets of emotions, we're beginning to understand the intriguing
03:48and surprising ways in which feelings underpin every single moment of our lives.
04:05For centuries, emotions have been the domain of artists and writers.
04:10At London's Globe Theatre, crowds come to watch plays performed just as they were in
04:14Shakespeare's day.
04:32Emotions are so variable and so personal, they seem out of the reach of science.
04:39But looking at these faces, you know what they're feeling, even if you can't explain
04:43why.
04:53Learning about the facial expression conveys so much.
05:15It takes a poet to be able to express in words what a moment in expression can convey.
05:21And what the face tells you is, that's what's happening right at the moment.
05:24This person's about to fight.
05:26This person is finding things very disfaceful and offensive.
05:30Right at the moment, they're having a great time, and you know that instantly, and you
05:36know that without words.
05:38And when you, the perceiver, see it, you don't necessarily translate it into words, you just
05:43know it, you feel it.
05:47Paul Ekman realised that our facial expressions are actually a powerful way to let others
05:52see what we are feeling.
06:01A theatre like this wouldn't work if you couldn't, at the back of the Globe, be able to distinguish
06:05each of the emotions, and that's just what our research found.
06:08But the most long-distance transmitter of all is the smile.
06:12You can recognise the smile at 70, 80 metres away.
06:17It's just about the distance that you could throw a rock or a spear.
06:2530 years ago, Paul Ekman travelled to Papua New Guinea.
06:29The work he did there was to become a landmark study of facial expressions.
06:39The young psychologist went to live with the last remaining Stone Age culture on Earth.
06:44In 1967 and 68, I worked in the highlands of New Guinea, which at that time had had
06:50no contact, really virtually no contact, with the outside world.
06:54Most of the people I studied, I was the first or second outsider they had seen, and they
06:58had never seen a photograph, a magazine, a mirror, television, film, nothing.
07:04Paul Ekman wanted to know whether the facial expressions used by people in the industrialised
07:10world were different from the expressions of these tribes.
07:14In other words, do facial expressions change as societies develop, or are they fixed and
07:20universal?
07:23I did two kinds of studies with them.
07:25I showed them photographs of people in the industrialised world.
07:29I did two kinds of studies with them.
07:32I showed them photographs and asked them to point to the one that fit a particular story.
07:37Point to the one where the person is angry, about to fight.
07:40Point to the one where he's just learned his child has died.
07:44And then I asked them to be actors and to show me their expression.
07:48You know, if a child had died, show me what your face would look like.
07:51If you were about to fight, show me your face.
07:53And I found exactly the same thing I had found elsewhere.
07:57Muscle for muscle, the facial expressions this ancient, isolated culture used
08:03were the same as our own.
08:05Ekman went on to suggest that these universal expressions revealed
08:09a simple set of core, universal human emotions,
08:13the basic ingredients of our entire emotional repertoire.
08:20The six basic facial expressions he identified were those of
08:25happiness,
08:27sadness,
08:29disgust,
08:31surprise,
08:33anger
08:35and fear.
08:39The question then is, how might these core, universal emotions
08:43each be generated by the brain?
08:51A Tuesday night in London's East End.
08:55MUSIC
09:02We all know what it's like to lose control,
09:04those moments when we're totally uninhibited.
09:15It's as though we're letting primitive urges,
09:17which are normally suppressed, take over.
09:25One of the first attempts at a complete theory
09:28of how emotions operate in the brain was based on exactly this idea.
09:37Our brains contain structures which we have inherited
09:40from our primitive ancestors.
09:42The brainstem, which controls sleeping and breathing,
09:45dates back to reptiles.
09:47Around that is the limbic system,
09:49which is present even in the earliest mammals.
09:52And on top of that, most recently evolved of all,
09:55is the cortex,
09:57linked to humans' higher thought processes,
10:00logic and reason.
10:04The big idea was that these three parts worked together
10:08in a rigid hierarchy with reason at the top.
10:11Moments of extreme emotion, like naked aggression,
10:14were seen as powerful drives
10:16coming from the reptilian parts of our brain
10:20and temporarily overriding the rational higher structures.
10:29In this early theory,
10:31emotion was completely separate from thought.
10:34But now we know that the brain doesn't work in such a simple way.
10:44Thoughts and emotions are totally intertwined.
10:47Emotions must be more than just reptilian urges
10:50slipping free from rational control.
10:52Imagine if I told you now that the boxer we'd just been watching
10:56had suddenly collapsed and got into a coma.
10:59I bet you'd feel something.
11:01Please rest assured that he is actually fine,
11:04but the point I'm trying to make is this,
11:07that a mere thought can trigger an emotion.
11:17In this house is a strange laboratory.
11:25It's home to an unusual scientist
11:28who has become a world authority
11:31on one particularly powerful emotion.
11:36The scientist's name is Paul Rosin
11:39and he calls himself Dr Disgust.
11:42Ha-ha!
11:44Hello. Hello.
11:47We have a curiosity about it.
11:49If I say to you,
11:51here's something in this little bottle that smells disgusting,
11:54often you'll say, can I smell it?
11:56And then you smell it and say, eww, it's disgusting.
11:59I mean, why did you even want to smell it?
12:04Paul Rosin is a scientist
12:06who has been studying the effects of emotion
12:10Paul Rosin has spent 20 years disgusting people.
12:14He's been investigating
12:16how thoughts and emotions become linked as we grow up.
12:20Disgust seems to be about food and it's about the mouth.
12:24The disgust face is around the mouth.
12:27And yet I realised pretty early
12:30that most of the examples of disgust that we ran into
12:33were not about food.
12:35There's disgust at touching things that are dead,
12:39there's disgust at seeing blood or gore.
12:41People would say certain kinds of unnatural sex is disgusting.
12:45People would say that certain people were disgusting.
12:48So the question is what was the relation
12:50between the original food core of disgust
12:53and all these other things?
12:58It's been a dirty business
13:00involving a range of unsuspecting victims
13:03and lots of messy foods.
13:05Put some ketchup on it.
13:08Now, how would you like to have that?
13:10No!
13:12Anyone with children
13:14knows how quickly they learn what they do and don't like to eat.
13:18Would you like to eat that?
13:20By three or four, they've learnt there's a basic distinction
13:23between food and things that shouldn't be eaten.
13:26Crayon?
13:27No, that's from drawing.
13:30Would you like to lick it even?
13:32No.
13:33How about touching it?
13:34No.
13:35No?
13:36No.
13:37Do you know what that is?
13:38A poopy.
13:39That's right, that's a doggy poopy.
13:41Would you like to eat that?
13:43No.
13:44You don't want to eat it?
13:46It's yucky.
13:48I don't want that.
13:50Would you touch it?
13:52No.
13:53Would you eat it?
13:54No.
13:55Little Cleo, at 14 months, will try anything once.
13:59She will only reject things if they taste bad.
14:02And since this is chocolate fudge,
14:05she's not going to learn that lesson today.
14:07So for a one-year-old child
14:09who will eat virtually anything in its way,
14:11food is just something that's a lump out there
14:14that you can taste and either reject or accept
14:16depending on whether it tastes good.
14:18For a three-year-old already,
14:20there's some things that just are not to be eaten.
14:23They're not because of their taste only.
14:25They seem just inappropriate and offensive.
14:28So within a few years,
14:30disgust is felt not just because something tastes bad
14:34but because of more sophisticated ideas we've acquired.
14:36For Rosin, one key landmark
14:38is the emergence of the concept of contamination.
14:41You know what that is?
14:42A bug, and I don't want it.
14:44No bugs.
14:45It's a cockroach.
14:47And I'm going to put it on this little spoon
14:50and drop it in your juice over there.
14:53Maybe stir it around a little.
14:56We're going to stir it around a little.
14:58I'm not going to eat that.
15:00Are you going to eat that?
15:01No.
15:02Why not?
15:04Would you drink some of that apple juice?
15:07Yeah, but I can't drink the bug.
15:10You don't want to drink that juice?
15:13But I don't want to drink the bug.
15:16OK, now suppose I take the cockroach out of the juice.
15:20It's pretty easy to identify with the idea
15:22that the juice has been contaminated.
15:24But we're not born with ideas like that.
15:27So when does this association develop?
15:29No thanks.
15:32By seven years of age, as we saw with Richard,
15:35the juice is still bad after the cockroach is gone.
15:38He has a much higher cognitive level
15:41of perceiving the situation.
15:43He is seeing this as the history of the juice.
15:46Something was left in the juice, even though it's invisible.
15:49The thought of the cockroach
15:51seems to confuse slightly younger children.
15:54There he is.
15:55Is it legs in it?
15:57No, look, you in there.
15:58At four, Zach is not keen
16:01and he takes a bit of persuading.
16:03I'll taste it.
16:05Sure you will.
16:07Though they would not eat a cockroach,
16:09they found it offensive,
16:11they were happy to drink the juice
16:13after the cockroach was removed.
16:15So they still don't have a sense of contamination.
16:17Then put it on the plate.
16:19How about drinking the apple juice now?
16:21Yeah.
16:22OK.
16:23To an adult, what Eli's doing is disgusting.
16:27Now, this is a Nazi hat from World War II.
16:31It's got a swastika on it, as you can see.
16:33Rosen believes that these sophisticated adult reactions
16:36to abstract ideas
16:38all somehow develop from the basic response
16:41to something that tastes disgusting.
16:43OK, thank you, that's fine.
16:45It sort of seems to start as a get-it-out-of-my-mouth emotion
16:49in respect to bad-tasting foods or offensive foods.
16:54It ends up an emotion that is very broad
16:56that seems to be about anything offensive.
16:58It's sort of get-it-out-of-my-mind
17:00or even get-it-out-of-my-soul.
17:02I want to be a better person
17:04by not having to interact with this thing.
17:06I sometimes think of it as the emotion of civilization.
17:09If you imagine somebody who doesn't have disgust,
17:12you'd think they were uncivilized.
17:14You know what this is, right?
17:16Mm-hmm.
17:17That's a bedpan.
17:18It's a brand-new bedpan.
17:20Never been used for its proper purpose.
17:23I'm going to take some apple juice now
17:26and I'm going to pour it into the bedpan.
17:31Now, would you be willing to pick up the bedpan
17:34and drink some apple juice from the bedpan?
17:36It's a brand-new bedpan.
17:38No, I can't do it.
17:40OK, that's fine.
17:45If all disgust involves the same basic emotion,
17:50might there be a disgust centre in the brain?
17:53It would be active whenever we find anything disgusting.
18:00An obvious way to search for the physical source of an emotion
18:03is to scan someone while they're actually experiencing it.
18:06I think I'm about to be totally disgusted.
18:13Inside the scanner, I'm shown various images
18:16designed to evoke the emotion of disgust.
18:20MUSIC PLAYS
18:28There's activity all over my brain,
18:31but one structure seems to be particularly active
18:34when I'm feeling disgusted.
18:36The anterior insula.
18:41What's interesting about this region
18:43is that it is also very active
18:45when we feel something unpleasant or painful in the gut.
18:50MUSIC CONTINUES
18:54The insula seems to be important in helping us to detect
18:58that something unpleasant is in our gut,
19:01whether that be literally, physically,
19:03or more metaphorically, as in being disgusted
19:06in normal sort of social circumstances.
19:09So even if you haven't literally got something unpleasant
19:13in your mouth, your brain is acting?
19:15Acting as if there were.
19:18So the insula is specifically involved in disgust.
19:22But is this tiny bit of brain
19:24responsible for the whole feeling of being disgusted?
19:30I don't think so.
19:32When people are shown the face of someone else being disgusted,
19:36the insula is just as active,
19:38even though the person being scanned
19:40isn't themselves feeling the emotion.
19:43The insula seems to be involved
19:46in helping us develop this feeling of disgust per se
19:49and feeling that something unpleasant is inside us,
19:52but it also helps us recognise disgust in other people.
19:55So if we see disgust in someone else's face,
19:58it's like a warning to us that, yes, there's disgust around,
20:01but we don't have to actually go through the process
20:04of being disgusted, vomiting, etc, ourselves.
20:07So there seems to be a brain area specialising in disgust,
20:11but it doesn't, on its own,
20:13produce the actual feeling of being disgusted.
20:18And do the other emotions have their own distinct areas?
20:21No-one has yet found specialist structures
20:24for anger, sadness, happiness or surprise.
20:29Only one other emotion
20:31seems to involve a specialised brain region.
20:34Fear.
20:43Fear is the most powerful and primal emotion of all.
21:07There's nothing like being in a firefight
21:11because it gets everything moving.
21:13Every emotion you ever sustain,
21:16you've got that within two minutes of a firefight.
21:19It was a very frightening thing.
21:25You lay there, you're helpless
21:27because you don't know where they are.
21:29They're throwing grenades at you.
21:31They're shooting machine guns at you.
21:33You don't know if you can get up, run.
21:36There's no hiding because they'll find you.
21:40They're taking you down.
21:57Nam was hell.
22:01Nam took our souls, took my soul
22:04and took it away from me.
22:07Whatever goodness, real goodness I had,
22:10the happiness, it's still over there somewhere.
22:16Psychiatrist Doug Bremner
22:18has been working for ten years with patients like Dennis
22:21who have been permanently traumatised
22:23by the terror they experienced in Vietnam.
22:27Dennis has symptoms of post-traumatic stress disorder
22:30including intrusive memories of the war
22:33that come back to him at any time of the day
22:37in which he has little control over
22:39and they replay in a repetitive manner.
22:42He has nightmares of the war.
22:45He's jumpy and easily startled
22:48and he's hyper-vigilant and on guard all the time.
22:53Nearly a fifth of Vietnam vets returned,
22:56like Dennis, traumatised.
23:01I feel trapped in my life.
23:04I feel like I'm trapped in some kind of shell,
23:07something that's never going to go away.
23:11I'm suicidal at times
23:14and hopelessness, you know.
23:18And the dreams, I think because of
23:21thinking about Vietnam so much
23:23and how hopeless that situation is,
23:25I just kind of carried it into my life today.
23:34I don't like busy streets all that much.
23:36I try to stay away from it.
23:40Walking in the streets of New York or somewhere
23:42I'm a little more watchful,
23:46you know, of the ambush.
23:52Someone like Dennis knows that
23:54anyone could pop out of the bushes
23:57at any time with a gun and shoot you
23:59and there's nothing that you can do about that.
24:02And he walks around with that knowledge all the time.
24:05But that makes it more difficult for him
24:08to work and to be close to his family
24:11and to do all those other things that we all take for granted.
24:17Dennis is on a hair-trigger to fear.
24:20Cars backfiring or just the smell of diesel
24:23take him back to Vietnam.
24:27All right, I need a perimeter set up here, quick!
24:31Come on, man.
24:33I need a perimeter set up around us.
24:36Get another company in there.
24:39Hey, get him!
24:57So what has changed in Dennis' brain to leave him so fearful?
25:04Doug Bremner exposes Dennis
25:06to vivid reminders of the Vietnam War,
25:09pictures and sounds designed to frighten
25:12in order to study the brain circuits
25:15involved in the fear response.
25:18One current theory is that fear
25:21involves two separate pathways in the brain.
25:25Any potential threat activates a specialised fear structure
25:29called the amygdala,
25:31which automatically sends out signals triggering responses
25:35like sweaty palms or increased heart rate.
25:41But a slower, second circuit routes right through the cortex.
25:45This is how we weigh up the threat.
25:48And if it's a false alarm, the amygdala is shut down.
25:52So it's a delicate balance.
25:54You need the primitive part of the brain to survive
25:57to turn on the fear response,
25:59but you don't want the fear response
26:01to become so incapacitating that you can't think.
26:04Could this balance have been upset in Dennis' brain?
26:11Doug Bremner has looked at the brain activity
26:14in traumatised veterans
26:16compared with those who have come through unscathed.
26:20He's found there's far less activity
26:22in one particular area of Dennis' cortex than there should be.
26:26This area is part of the pathway
26:29which normally shuts down the automatic fear responses
26:32when they're not needed.
26:34So in Dennis' brain,
26:36even the slightest threat unleashes the full terror.
26:41So why can't Dennis control his fear responses?
26:44Doug Bremner thinks that the best clue
26:47comes from the way patients like Dennis
26:50seem to dwell on their memories of the war.
26:57One of the things that I found most interesting
27:00when I first began working with Dennis
27:03was the fact that he had a lot of fear.
27:07One of the things that I found most interesting
27:10when I first began working with Vietnam veterans
27:13was that many of my patients,
27:15they could remember what happened in Vietnam
27:18as if it were yesterday,
27:20and they'd show me picture books of their friends from the war
27:23and talk about them as if they had just seen them the day before.
27:26But they couldn't remember what they had for breakfast that morning.
27:29They had sort of a vague idea
27:31about maybe how long they'd been in the hospital.
27:34But the more recent things, they had a lot of problems with.
27:40Bremner believes that Dennis' faulty fear response
27:43also involves a brain structure called the hippocampus,
27:47known to play a vital role in memory.
27:55We did an MRI scan on Dennis,
27:58and this is his hippocampus here, this grey area there,
28:03and it's visibly...
28:05I can just look at the scan and tell you that it's smaller in volume
28:09compared to a normal individual
28:12where the hippocampus is much larger.
28:15This change to Dennis' hippocampus is very exciting.
28:20Constant terror has changed the structure of his brain.
28:26This is from the land we left so much at.
28:29It's incredible.
28:32It's as if his experiences in Vietnam
28:34have worn such a deep groove that he's trapped in the past.
28:38Even a handful of soil from the Ho Chi tunnels
28:41is enough to reduce him to tears.
29:02Emotions have long-lasting effects on all of us.
29:13Emotions are what make those landmark moments from childhood
29:17so memorable.
29:24Everyone remembers their first day at school.
29:27For me, it was here in this daunting assembly hall,
29:32almost 40 years ago.
29:34All the new girls had to assemble on these steps
29:37and wait to be allocated their class.
29:39I remember vividly wearing a very baggy uniform
29:42with the expectation that I'd grow into it,
29:45clutching my brand-new satchel on my knee,
29:48feeling very lonely and very small.
29:55Emotional experiences make us who we are.
29:59Our own personal histories are woven into the fabric of our brains.
30:07But it's not just moments of extreme emotion that leave their mark.
30:17Every day, the aftershocks of past emotional upheavals
30:20are influencing our actions.
30:22As we go through life,
30:24these aftershocks are silently nudging us towards decisions.
30:28We are oblivious to this process,
30:30but every moment of our lives,
30:32we are influenced by the footprints of our past.
30:49Emotion is about value.
30:51Emotion is about what's good, what's evil,
30:54what's pleasant, what's unpleasant,
30:57and what's possible.
30:59If you take away that,
31:01you do not have a value system to operate effectively.
31:04Here in Chicago,
31:06neurologist Antonio Damasio
31:08has done some insightful studies
31:10into the role of emotions in everyday life.
31:17He's interested in how emotions influence us
31:20at those times when we feel it our most logical,
31:23when we're trying to make difficult decisions.
31:27And he's invented a gambling game to prove his point.
31:34I turn over cards and either win or lose money,
31:37but he doesn't tell me why.
31:39The payouts vary wildly.
31:41They're deliberately designed to confuse.
31:45So there's some rule operating here that I can't work out.
31:48OK.
31:50Another black.
31:52And you're going to get $50 as well.
31:55But determined to work out which packs are paying out more.
31:59It's very tempting to just do it randomly,
32:02but that's completely non-logical to do that.
32:05I can't see any relationship between what I'm doing
32:08and what is happening to me.
32:10A bit like life, I suppose. OK.
32:12So A.
32:14That is going to be, I'm afraid to say, 1,150 for me.
32:17But I will give you 100.
32:19So...
32:21Well, that's just being kind?
32:24No, no, no, it's just the rules.
32:26Oh, I see.
32:28I'm trying my best to unravel the rules of the game.
32:31But the pattern of payouts is so complicated,
32:34I can't work it out logically.
32:36So I'm forced to use something else.
32:38My emotions.
32:40Although they give the highest rewards,
32:42I get the feeling that packs A and B also seem to inflict more damage.
32:46And that steers me away from them.
32:49OK.
32:52C.
32:53I'm being guided by emotionally loaded but covert signals,
32:58what Damasio calls somatic markers.
33:01D.
33:02Eventually, I adopt a more conservative policy.
33:0550. OK.
33:07Next.
33:08D.
33:09Winning back my losses by sticking to packs C and D.
33:12Yes. OK.
33:15D.
33:17That's going to be another 50, and that's the end.
33:20Mm-hm.
33:21So how do you know it's the end?
33:23Oh, because I decide.
33:25So what is odd is that I was trying to use all the logic
33:29within my abilities and trying different logical strategies,
33:32but none of them seemed to work.
33:34None of them seemed adequate.
33:36There seems more to it than logic.
33:38Logical alone really does not help you solve problems
33:41in which there's as much uncertainty as you had here.
33:44What we do most of the time is that we use, of course, logic
33:48and we use knowledge, no question about it,
33:51but we also use something very smart,
33:54which is the experience that we've had in the past
33:59of certain situations and of the outcomes of certain actions
34:03that we have taken, and the attached emotion.
34:08So when I'm deciding which pack to choose,
34:12I'm aware of the consequences of my earlier decisions.
34:16These good or bad feelings,
34:18which Damasio calls somatic markers, guide our choices.
34:24But I wasn't always aware of feeling anything
34:27when I was deciding which pack to choose.
34:33When you confronted a very large penalty
34:36and you actually had to pay quite a lot of money,
34:41you were at the gut-feeling level,
34:43this very old idea, very traditional.
34:45But throughout most of the task,
34:47you were actually not having that kind of signal.
34:50You were having something that was far more subtle,
34:53that was happening without you knowing,
34:55below the level of consciousness.
35:00It's possible to measure these unconscious somatic markers.
35:04After a car turn,
35:06electrical sensors can pick up a tiny increase in sweat,
35:11indicating an emotional response to the result.
35:14But these changes are also detected just before the car turn,
35:18as the actual decision is being made.
35:21So unconsciously, emotions are guiding our every move.
35:41Emotions guide our behaviour.
35:43They make us want to do things.
35:45They are the driving force that becomes action,
35:48that indescribable brain kick
35:50that makes what we do worth doing.
35:54Feelings motivate us to try, to care, to win.
35:59That rush, that thrill that makes certain moments so special,
36:04it's something else.
36:06Feelings motivate us to try, to care, to win.
36:24That rush, that thrill that makes certain moments so special.
36:48For scientists, the nature of subjective experience has always been slippery.
36:53How can you measure what you can barely describe?
36:56But now, at last, we are able to tackle the really big question.
37:00Where does the actual feel of feelings come from?
37:08Here in San Francisco, Dr Rebecca Turner has chosen to study
37:13that most longed-for feeling of all, love.
37:17It's very difficult for a scientist to use a term like love,
37:21which has typically been the domain of poets and artists.
37:30She's trying to pin down what it is about being in love
37:34that creates such powerful emotions.
37:40So we want to know about relationships and relationships
37:44and we want to know about relationships, intimacy and emotions.
37:49Why do we have our strongest emotions in relationships
37:53in ways that seem completely beyond our control?
37:56And why do we suffer so much when someone goes away?
38:08I remember when my husband asked me to marry him
38:12and I remember exactly, we were in my apartment
38:18and we were sitting on the floor in the sun in the morning
38:21and I remember he asked me if I'd share my life with him
38:26and it was wonderful.
38:28I felt so loved and I loved him so much
38:32and I was so ready to really commit myself to someone, to be with him.
38:38As Shoshana remembers happy times with her husband-to-be,
38:42a nurse takes a blood sample.
38:44Turner and her team are interested in a hormone called oxytocin.
38:49We'd only been together actually two weeks.
38:54We've known about oxytocin for a long time.
38:57It plays an important role in many reproductive behaviours,
39:01breastfeeding, childbirth and orgasm.
39:05And recently it's emerged that oxytocin must also have a role
39:10in brain function.
39:12What's interesting is that there are oxytocin receptors
39:15throughout the human brain, in the limbic system and in the brain stem.
39:19So they're in areas that are associated with emotion
39:22and the autonomic control of emotion.
39:26If oxytocin is released into the blood during reproductive behaviours
39:31and it's active in the brain,
39:33could it be the basis of the emotional feelings of love?
39:42We found that when experiencing positive emotion,
39:46particularly about relationships,
39:48some women experience surges of oxytocin.
39:52When they were talking about sad feelings,
39:55having lost someone that they love, their oxytocin levels decreased.
40:01I think about the fact that since my mother passed away several years ago,
40:06she will never meet my child.
40:09And she would have been a great-grandmother.
40:12And that's really sad. It's hard.
40:16So, oxytocin levels do seem to rise and fall
40:20in relation to the level of loving attachment the volunteers felt.
40:24With neuroscientific techniques and what we're starting to learn
40:28about the brain and emotion and behaviour,
40:31it's reasonable to think of oxytocin as something that can influence loving
40:36and certainly patterns of loving and behaviours that we associate with loving.
40:42But does that mean that a surge in brain oxytocin
40:46is what produces the feeling of love?
40:49I don't think it's that simple.
40:51In theory, some totally different brain process
40:55could be producing that loving feeling
40:57and the changes in oxytocin might just be a side effect.
41:01But overall, it's now clear that there is some kind of relationship
41:05between the ebb and flow of our feelings
41:08and the many chemicals in our brains.
41:15We know that we can influence the way we feel
41:18by deliberately changing our brain chemistry.
41:21We do it all the time with drugs such as coffee, nicotine and alcohol.
41:26Here in Chicago, one scientist has been experimenting with drugs.
41:33Drugs serve a very useful function in the study of emotion
41:37because they stimulate the very system that's activated in a natural situation
41:42when people go through an emotional situation.
41:45So we can use them as a tool to stimulate the limbic system.
41:51Harriet DeWitt has devised a cunning experiment
41:54to test the effects of one drug, a stimulant, amphetamine.
41:59Two of the volunteers are told they've been given an inactive placebo pill,
42:03the other two that they've been given a stimulant.
42:06In fact, all four have taken a dose of amphetamine.
42:12Drugs like amphetamine work by mimicking natural biochemicals in the brain.
42:17So if changes in biochemistry are all there is to experiencing an emotion,
42:21all the subjects should feel the same,
42:24whether they know they've taken a drug or not.
42:29Half an hour into the experiment and the amphetamine begins to take effect.
42:34All the subjects will be experiencing an overall increase in arousal.
42:39They become restless.
42:41Tim and Ryan know they've taken a stimulant
42:44and are out of their seats already.
42:46But how will the unsuspecting Brooke and Mike react?
42:50We saw quite clearly that the people who were expecting to receive a placebo
42:55interpreted the sensations that they experienced quite differently
43:00and they experienced them in a more negative way.
43:03They felt jittery, they felt anxious, they didn't enjoy the experience.
43:09And in contrast, the people who knew that they were going to get a stimulant drug
43:15recognized and identified the sensations that they experienced
43:19as being due to the drug and they actually enjoyed the drug effect.
43:23They felt energized, they felt focused, they talked more, they were amusing.
43:28So their behaviour was really quite different
43:31and each of their experiences of the effects of the drug were quite different,
43:36just simply depending on what they were expecting to receive.
43:40Hi, I'm Ed Chavellari, born June 4th, 1975.
43:45I am single.
43:47I found a pebble on the floor which has caught my interest.
43:51Their different responses reveal a great deal
43:54about the way subjective feeling is processed in the brain.
43:59I'm trying to flick it up on my foot like a football.
44:02I think it tells us that the basic physiological responses
44:07that are involved in emotion are really only a part of the emotion
44:12and what makes the experience that we describe as an anxious emotion
44:17or a positive emotion is very strongly influenced
44:21by the person's understanding of the situation
44:24and the person's interpretation of the situation.
44:30So even though they've all taken exactly the same drug,
44:34their experiences are quite different.
44:39The feeling of an emotion must be generated by something more
44:44than merely the presence of drug molecules in the brain.
45:04MUSIC PLAYS
45:20We've come a long way from the old idea
45:23of primitive brain regions unleashing an emotion
45:26and now we know that emotions aren't simply some biochemical change
45:30flooding the system wholesale.
45:32Perhaps the mistake has been to think of emotions
45:35as some kind of an occasional event that can be switched on or off.
45:39Surely any explanation of how we feel should deal with the fact
45:43that emotions are with us all the time.
45:50Whatever generates feelings must be somewhere in the brain's
45:54endlessly shifting patterns of activity.
45:58So far, science has only been able to show what emotions are not,
46:02but over the last few years, I've been trying to work out
46:06what really might be going on.
46:08Although I think emotions are always with us,
46:11it's easiest to deal with moments of extreme emotion.
46:14Whether it's the thrill of the fairground ride or a blind rage,
46:18extreme emotions are all about living in the here and now.
46:22In the heat of the moment, our whole brain is caught up
46:25in a rush of sensory processing,
46:27a deafening roar that drowns out our rational, measured minds.
46:31It's all about losing yourself and just experiencing.
46:34Perhaps it is this extreme, passive, sensual state
46:38that is all there is to an emotional high.
46:43But how does that translate into the feel of feelings?
46:48If there is no special area, or single chemical change,
46:52what is the source of the visceral nature of emotions?
47:09In my view, emotions are a natural part of life.
47:14In my view, the first-hand feel of different emotional states
47:19must actually emerge directly from the ever-changing patterns
47:23of neuronal circuits firing in the brain.
47:39At the moment, this is just a theory.
47:42The ultimate test would be to find a way to monitor
47:45these swiftly changing configurations of neurons in the brain
47:48whilst someone was experiencing different emotions.
47:51I'm convinced that in this new century, we'll be able to do just that.
47:58Only then, when we have a way to measure feelings flashing through the brain,
48:03will scientists really have the tools to unlock the secrets of emotion.
48:13In the next programme,
48:15how the brain is constantly distorting our view of the world.
48:20It feels as though we just open our eyes and see what's there.
48:25But nothing could be further from the truth.
48:42Transcription by ESO. Translation by —