0:00:00.880,0:00:04.318
"Pheromone" is a very powerful word.

0:00:04.318,0:00:08.462
It conjures up sex, abandon, loss of control,

0:00:08.462,0:00:12.154
and you can see, it's very important as a word.

0:00:12.154,0:00:17.437
But it's only 50 years old. It was invented in 1959.

0:00:17.437,0:00:19.986
Now, if you put that word into the web,

0:00:19.986,0:00:21.496
as you may have done,

0:00:21.496,0:00:23.888
you'll come up with millions of hits,

0:00:23.888,0:00:26.533
and almost all of those sites are trying to sell you

0:00:26.533,0:00:28.792
something to make you irresistible

0:00:28.792,0:00:31.865
for 10 dollars or more.

0:00:31.865,0:00:34.088
Now, this is a very attractive idea,

0:00:34.088,0:00:36.530
and the molecules they mention

0:00:36.530,0:00:38.444
sound really science-y.

0:00:38.444,0:00:40.028
They've got lots of syllables.

0:00:40.028,0:00:42.901
It's things like androstenol, androstenone

0:00:42.901,0:00:45.342
or androstadienone.

0:00:45.342,0:00:46.984
It gets better and better,

0:00:46.984,0:00:49.774
and when you combine that with white lab coats,

0:00:49.774,0:00:51.186
you must imagine that there is

0:00:51.186,0:00:53.700
fantastic science behind this.

0:00:53.700,0:00:58.822
But sadly, these are fraudulent claims

0:00:58.822,0:01:02.161
supported by dodgy science.

0:01:02.161,0:01:04.779
The problem is that, although there are many

0:01:04.779,0:01:07.324
good scientists working on what they think

0:01:07.324,0:01:09.194
are human pheromones,

0:01:09.194,0:01:11.799
and they're publishing in respectable journals,

0:01:11.799,0:01:13.380
at the basis of this,

0:01:13.380,0:01:16.716
despite very sophisticated experiments,

0:01:16.716,0:01:19.269
there really is no good science behind it,

0:01:19.269,0:01:22.561
because it's based on a problem,

0:01:22.561,0:01:26.011
which is nobody has systematically gone through

0:01:26.011,0:01:28.112
all the odors that humans produce --

0:01:28.112,0:01:30.890
and there are thousands of[br]molecules that we give off.

0:01:30.890,0:01:34.000
We're mammals. We produce a lot of smell.

0:01:34.000,0:01:36.144
Nobody has gone through systematically

0:01:36.144,0:01:38.911
to work out which molecules really are pheromones.

0:01:38.911,0:01:40.541
They've just plucked a few,

0:01:40.541,0:01:42.430
and all these experiments are based on those,

0:01:42.430,0:01:45.440
but there's no good evidence at all.

0:01:45.440,0:01:47.618
Now, that's not to say

0:01:47.618,0:01:49.780
that smell is not important to people.

0:01:49.780,0:01:53.282
It is, and some people are real enthusiasts,

0:01:53.282,0:01:56.779
and one of these was Napoleon.

0:01:56.779,0:01:58.571
And famously, you may remember

0:01:58.571,0:02:01.668
that out on the campaign trail for war,

0:02:01.668,0:02:04.475
he wrote to his lover, Empress Josephine,

0:02:04.475,0:02:07.709
saying, "Don't wash. I'm coming home."

0:02:07.709,0:02:08.311
(Laughter)

0:02:08.311,0:02:11.232
So he didn't want to lose any of her richness

0:02:11.232,0:02:13.581
in the days before he'd get home,

0:02:13.581,0:02:15.958
and it is still, you'll find websites

0:02:15.958,0:02:19.860
that offer this as a major quirk.

0:02:19.860,0:02:21.024
At the same time, though,

0:02:21.024,0:02:23.477
we spend about as much money

0:02:23.477,0:02:25.248
taking the smells off us

0:02:25.248,0:02:27.969
as putting them back on in perfumes,

0:02:27.969,0:02:32.160
and perfumes are a multi-billion-dollar business.

0:02:32.160,0:02:34.563
So what I want to do in the rest of this talk

0:02:34.563,0:02:39.841
is tell you about what pheromones really are,

0:02:39.841,0:02:42.839
tell you why I think we would expect

0:02:42.839,0:02:45.587
humans to have pheromones,

0:02:45.587,0:02:50.080
tell you about some of the[br]confusions in pheromones,

0:02:50.080,0:02:52.872
and then finally, I want to end with

0:02:52.872,0:02:54.842
a promising avenue which shows us

0:02:54.842,0:02:58.990
the way we ought to be going.

0:02:58.990,0:03:03.171
So the ancient Greeks knew

0:03:03.171,0:03:07.225
that dogs sent invisible signals between each other.

0:03:07.225,0:03:09.599
A female dog in heat

0:03:09.599,0:03:11.515
sent an invisible signal to male dogs

0:03:11.515,0:03:12.970
for miles around,

0:03:12.970,0:03:15.075
and it wasn't a sound, it was a smell.

0:03:15.075,0:03:17.256
You could take the smell from the female dog,

0:03:17.256,0:03:19.719
and the dogs would chase the cloth.

0:03:19.719,0:03:21.327
But the problem for everybody

0:03:21.327,0:03:23.440
who could see this effect

0:03:23.440,0:03:25.062
was that you couldn't identify the molecules.

0:03:25.062,0:03:27.515
You couldn't demonstrate it was chemical.

0:03:27.515,0:03:28.830
The reason for that, of course,

0:03:28.830,0:03:30.245
is that each of these animals

0:03:30.245,0:03:31.851
produces tiny quantities,

0:03:31.851,0:03:33.510
and in the case of the dog,

0:03:33.510,0:03:36.412
males dogs can smell it, but we can't smell it.

0:03:36.412,0:03:40.770
And it was only in 1959 that a German team,

0:03:40.770,0:03:44.122
after spending 20 years in[br]search of these molecules,

0:03:44.122,0:03:47.903
discovered, identified, the first pheromone,

0:03:47.903,0:03:51.181
and this was the sex pheromone of a silk moth.

0:03:51.181,0:03:54.855
Now, this was an inspired choice [br]by Adolf Butenandt and his team,

0:03:54.855,0:03:56.981
because he needed half a million moths

0:03:56.981,0:04:00.008
to get enough material to do the chemical analysis.

0:04:00.008,0:04:02.097
But he created the model

0:04:02.097,0:04:04.461
for how you should go about pheromone analysis.

0:04:04.461,0:04:07.142
He basically went through systematically,

0:04:07.142,0:04:10.087
showing that only the molecule in question

0:04:10.087,0:04:11.953
was the one that stimulated the males,

0:04:11.953,0:04:14.006
not all the others.

0:04:14.006,0:04:16.164
He analyzed it very carefully.

0:04:16.164,0:04:17.981
He synthesized the molecule,

0:04:17.981,0:04:21.289
and then tried the synthesized[br]molecule on the males

0:04:21.289,0:04:24.150
and got them to respond and showed it was,

0:04:24.150,0:04:25.910
indeed, that molecule.

0:04:25.910,0:04:28.060
That's closing the circle.

0:04:28.060,0:04:30.765
That's the thing which has[br]never been done with humans:

0:04:30.765,0:04:34.375
nothing systematic, no real demonstration.

0:04:34.375,0:04:36.109
With that new concept,

0:04:36.109,0:04:37.818
we needed a new word,

0:04:37.818,0:04:40.653
and that was the word "pheromone,"

0:04:40.653,0:04:44.254
and it's basically transferred excitement,

0:04:44.254,0:04:46.523
transferred between individuals,

0:04:46.523,0:04:49.349
and since 1959, pheromones have been found

0:04:49.349,0:04:51.224
right the way across the animal kingdom,

0:04:51.224,0:04:53.426
in male animals, in female animals.

0:04:53.426,0:04:54.971
It works just as well underwater

0:04:54.971,0:04:56.993
for goldfish and lobsters.

0:04:56.993,0:04:58.740
And almost every mammal you can think of

0:04:58.740,0:05:00.563
has had a pheromone identified,

0:05:00.563,0:05:04.393
and of course, an enormous number of insects.

0:05:04.393,0:05:06.362
So we know that pheromones exist

0:05:06.362,0:05:09.423
right the way across the animal kingdom.

0:05:09.423,0:05:11.196
What about humans?

0:05:11.196,0:05:12.444
Well, the first thing, of course,

0:05:12.444,0:05:14.101
is that we're mammals,

0:05:14.101,0:05:15.660
and mammals are smelly.

0:05:15.660,0:05:17.536
As any dog owner can tell you,

0:05:17.536,0:05:19.517
we smell, they smell.

0:05:19.517,0:05:21.498
But the real reason we might think

0:05:21.498,0:05:23.323
that humans have pheromones

0:05:23.323,0:05:26.541
is the change that occurs as we grow up.

0:05:26.541,0:05:28.992
The smell of a room of teenagers

0:05:28.992,0:05:30.481
is quite different

0:05:30.481,0:05:33.301
from the smell of a room of small children.

0:05:33.301,0:05:36.173
What's changed? And of course, it's puberty.

0:05:36.173,0:05:37.632
Along with the pubic hair

0:05:37.632,0:05:39.325
and the hair in the armpits,

0:05:39.325,0:05:43.067
new glands start to secrete in those places,

0:05:43.067,0:05:45.682
and that's what's making the change in smell.

0:05:45.682,0:05:47.830
If we were any other kind of mammal,

0:05:47.830,0:05:49.019
or any other kind of animal,

0:05:49.019,0:05:50.156
we would say,

0:05:50.156,0:05:52.028
"That must be something to do with pheromones,"

0:05:52.028,0:05:54.684
and we'd start looking properly.

0:05:54.684,0:05:56.660
But there are some problems, and this is why,

0:05:56.660,0:05:59.729
I think, people have not looked for

0:05:59.729,0:06:02.646
pheromones so effectively in humans.

0:06:02.646,0:06:04.217
There are, indeed, problems.

0:06:04.217,0:06:06.401
And the first of these

0:06:06.401,0:06:07.918
is perhaps surprising.

0:06:07.918,0:06:09.752
It's all about culture.

0:06:09.752,0:06:11.899
Now moths don't learn a lot

0:06:11.899,0:06:15.516
about what is good to smell, but humans do,

0:06:15.516,0:06:17.362
and up to the age of about four,

0:06:17.362,0:06:20.081
any smell, no matter how rancid,

0:06:20.081,0:06:21.880
is simply interesting.

0:06:21.880,0:06:23.932
And I understand that the major role of parents

0:06:23.932,0:06:27.613
is to stop kids putting their fingers in poo,

0:06:27.613,0:06:30.411
because it's always something nice to smell.

0:06:30.411,0:06:33.102
But gradually we learn what's not good,

0:06:33.102,0:06:34.592
and one of the things we learn

0:06:34.592,0:06:36.727
at the same time as what is not good

0:06:36.727,0:06:38.485
is what is good.

0:06:38.485,0:06:40.747
Now, the cheese behind me

0:06:40.747,0:06:44.698
is a British, if not an English, delicacy.

0:06:44.698,0:06:48.135
It's ripe blue Stilton.

0:06:48.135,0:06:52.497
Liking it is incomprehensible to[br]people from other countries.

0:06:52.497,0:06:55.782
Every culture has its own special food

0:06:55.782,0:06:57.878
and national delicacy.

0:06:57.878,0:06:59.930
If you were to come from Iceland,

0:06:59.930,0:07:01.254
your national dish

0:07:01.254,0:07:04.230
is deep rotted shark.

0:07:04.230,0:07:06.360
Now, all of these things are acquired tastes,

0:07:06.360,0:07:09.520
but they form almost a badge of identity.

0:07:09.520,0:07:14.340
You're part of the in-group.

0:07:14.340,0:07:17.922
The second thing is the sense of smell.

0:07:17.922,0:07:21.391
Each of us has a unique odor world,

0:07:21.391,0:07:23.930
in the sense that what we smell,

0:07:23.930,0:07:26.789
we each smell a completely different world.

0:07:26.789,0:07:28.498
Now, smell was the hardest

0:07:28.498,0:07:30.359
of the senses to crack,

0:07:30.359,0:07:32.074
and the Nobel Prize awarded to

0:07:32.074,0:07:33.707
Richard Axel and Linda Buck

0:07:33.707,0:07:36.140
was only awarded in 2004

0:07:36.140,0:07:38.930
for their discovery of how smell works.

0:07:38.930,0:07:40.307
It's really hard,

0:07:40.307,0:07:42.898
but in essence, nerves from the brain

0:07:42.898,0:07:45.111
go up into the nose

0:07:45.111,0:07:47.492
and on these nerves exposed in the nose

0:07:47.492,0:07:50.546
to the outside air are receptors,

0:07:50.546,0:07:53.695
and odor molecules coming in on a sniff

0:07:53.695,0:07:55.845
interact with these receptors,

0:07:55.845,0:08:00.104
and if they bond, they send the nerve a signal

0:08:00.104,0:08:02.412
which goes back into the brain.

0:08:02.412,0:08:04.474
We don't just have one kind of receptor.

0:08:04.474,0:08:06.350
If you're a human, you have about 400

0:08:06.350,0:08:08.415
different kinds of receptors,

0:08:08.415,0:08:11.382
and the brain knows what you're smelling

0:08:11.382,0:08:13.193
because of the combination of receptors

0:08:13.193,0:08:15.706
and nerve cells that they trigger,

0:08:15.706,0:08:17.264
sending messages up to the brain

0:08:17.264,0:08:20.170
in a combinatorial fashion.

0:08:20.170,0:08:21.160
But it's a bit more complicated,

0:08:21.160,0:08:23.295
because each of those 400

0:08:23.295,0:08:25.446
comes in various variants,

0:08:25.446,0:08:27.517
and depending which variant you have,

0:08:27.517,0:08:31.699
you might smell coriander, or cilantro, that herb,

0:08:31.699,0:08:34.317
either as something delicious and savory

0:08:34.317,0:08:36.491
or something like soap.

0:08:36.491,0:08:39.177
So we each have an individual world of smell,

0:08:39.177,0:08:40.818
and that complicates anything

0:08:40.818,0:08:43.114
when we're studying smell.

0:08:43.114,0:08:45.806
Well, we really ought to talk about armpits,

0:08:45.806,0:08:49.202
and I have to say that I do[br]have particularly good ones.

0:08:49.202,0:08:51.204
Now, I'm not going to share them with you,

0:08:51.204,0:08:53.183
but this is the place that most people

0:08:53.183,0:08:54.920
have looked for pheromones.

0:08:54.920,0:08:56.423
There is one good reason,

0:08:56.423,0:08:59.827
which is, the great apes have armpits

0:08:59.827,0:09:02.155
as their unique characteristic.

0:09:02.155,0:09:04.556
The other primates have scent glands

0:09:04.556,0:09:06.386
in other parts of the body.

0:09:06.386,0:09:08.740
The great apes have these armpits

0:09:08.740,0:09:10.957
full of secretory glands

0:09:10.957,0:09:13.298
producing smells all the time,

0:09:13.298,0:09:16.998
enormous numbers of molecules.

0:09:16.998,0:09:18.701
When they're secreted from the glands,

0:09:18.701,0:09:20.705
the molecules are odorless.

0:09:20.705,0:09:22.780
They have no smell at all,

0:09:22.780,0:09:24.749
and it's only the wonderful bacteria

0:09:24.749,0:09:26.962
growing on the rainforest of hair

0:09:26.962,0:09:28.418
that actually produces the smells

0:09:28.418,0:09:30.439
that we know and love.

0:09:30.439,0:09:32.339
And so incidentally, if you want to reduce

0:09:32.339,0:09:33.769
the amount of smell,

0:09:33.769,0:09:35.689
clear-cutting your armpits

0:09:35.689,0:09:37.945
is a very effective way of reducing

0:09:37.945,0:09:39.459
the habitat for bacteria,

0:09:39.459,0:09:41.796
and you'll find they remain less smelly

0:09:41.796,0:09:43.890
for much longer.

0:09:43.890,0:09:46.436
But although we've focused on armpits,

0:09:46.436,0:09:47.803
I think it's partly because they're the least

0:09:47.803,0:09:51.770
embarrassing place to go and ask people for samples.

0:09:51.770,0:09:54.382
There is actually another reason why we might not

0:09:54.382,0:09:57.158
be looking for a universal sex pheromone there,

0:09:57.158,0:10:00.997
and that's because 20 percent[br]of the world's population

0:10:00.997,0:10:04.442
doesn't have smelly armpits like me.

0:10:04.442,0:10:08.358
And these are people from China, Japan,

0:10:08.358,0:10:10.953
Korea, and other parts of northeast Asia.

0:10:10.953,0:10:14.477
They simply don't secrete those odorless precursors

0:10:14.477,0:10:18.730
that the bacteria love to use to produce the smells

0:10:18.730,0:10:21.079
that in an ethnocentric way we always thought of

0:10:21.079,0:10:23.184
as characteristic of armpits.

0:10:23.184,0:10:27.691
So it doesn't apply to 20 percent of the world.

0:10:27.691,0:10:30.693
So what should we be doing

0:10:30.693,0:10:33.746
in our search for human pheromones?

0:10:33.746,0:10:36.198
I'm fairly convinced that we do have them.

0:10:36.198,0:10:38.151
We're mammals, like everybody else

0:10:38.151,0:10:42.130
who's a mammal, and we probably do have them.

0:10:42.130,0:10:43.713
But what I think we should do

0:10:43.713,0:10:45.652
is go right back to the beginning,

0:10:45.652,0:10:47.991
and basically look all over the body.

0:10:47.991,0:10:49.682
No matter how embarrassing,

0:10:49.682,0:10:53.060
we need to search and go for the first time

0:10:53.060,0:10:55.520
where no one else has dared tread.

0:10:55.520,0:10:56.668
It's going to be difficult,

0:10:56.668,0:10:59.243
it's going to be embarrassing, but we need to look.

0:10:59.243,0:11:02.190
We also need to go back to the ideas

0:11:02.190,0:11:05.457
that Butenandt used when he[br]was studying the silk moth.

0:11:05.457,0:11:08.925
We need to go back and look systematically

0:11:08.925,0:11:11.063
at all the molecules that are being produced,

0:11:11.063,0:11:13.496
and work out which ones are really involved.

0:11:13.496,0:11:15.602
It isn't good enough simply to pluck a couple

0:11:15.602,0:11:17.546
and say, "They'll do."

0:11:17.546,0:11:18.945
We have to actually demonstrate

0:11:18.945,0:11:21.755
that they really have the effects we claim.

0:11:21.755,0:11:24.989
There is one team that I'm[br]actually very impressed by.

0:11:24.989,0:11:28.165
They're in France, and their previous success

0:11:28.165,0:11:32.542
was identifying the rabbit mammary pheromone.

0:11:32.542,0:11:35.111
They've turned their attention now

0:11:35.111,0:11:38.296
to human babies and mothers.

0:11:38.296,0:11:41.367
So this is a baby having a drink of milk

0:11:41.367,0:11:44.010
from its mother's breast.

0:11:44.010,0:11:46.193
Her nipple is completely hidden

0:11:46.193,0:11:47.439
by the baby's head,

0:11:47.439,0:11:51.190
but what you'll notice is a white droplet

0:11:51.190,0:11:52.971
with an arrow pointing to it,

0:11:52.971,0:11:56.170
and that's the secretion from the areolar glands.

0:11:56.170,0:11:59.160
Now, we all have them, men and women,

0:11:59.160,0:12:01.978
and these are the little bumps around the nipple,

0:12:01.978,0:12:03.937
and if you're a lactating woman,

0:12:03.937,0:12:06.274
these start to secrete.

0:12:06.274,0:12:08.863
It's a very interesting secretion.

0:12:08.863,0:12:11.866
What Benoist Schaal and his team developed

0:12:11.866,0:12:14.273
was a simple test to investigate

0:12:14.273,0:12:17.079
what the effect of this secretion might be,

0:12:17.079,0:12:20.055
in effect, a simple bioassay.

0:12:20.055,0:12:22.730
So this is a sleeping baby,

0:12:22.730,0:12:27.719
and under its nose, we've put a clean glass rod.

0:12:27.719,0:12:29.830
The baby remains sleeping,

0:12:29.830,0:12:32.171
showing no interest at all.

0:12:32.171,0:12:34.245
But if we go to any mother

0:12:34.245,0:12:36.674
who is secreting from the areolar glands,

0:12:36.674,0:12:38.251
so it's not about recognition,

0:12:38.251,0:12:40.479
it can be from any mother,

0:12:40.479,0:12:41.831
if we take the secretion

0:12:41.831,0:12:44.735
and now put it under the baby's nose,

0:12:44.735,0:12:46.826
we get a very different reaction.

0:12:46.826,0:12:49.810
It's a connoisseur's reaction of delight,

0:12:49.810,0:12:51.870
and it opens its mouth

0:12:51.870,0:12:53.523
and sticks out its tongue

0:12:53.523,0:12:55.610
and starts to suck.

0:12:55.610,0:12:57.950
Now, since this is from any mother,

0:12:57.950,0:12:59.742
it could really be a pheromone.

0:12:59.742,0:13:01.521
It's not about individual recognition.

0:13:01.521,0:13:03.397
Any mother will do.

0:13:03.397,0:13:04.860
Now, why is this important,

0:13:04.860,0:13:07.318
apart from being simply very interesting?

0:13:07.318,0:13:09.125
It's because women vary

0:13:09.125,0:13:11.898
in the number of areolar glands that they have,

0:13:11.898,0:13:14.094
and there is a correlation between the ease

0:13:14.094,0:13:16.636
with which babies start to suckle

0:13:16.636,0:13:18.498
and the number of areolar glands she has.

0:13:18.498,0:13:21.296
It appears that the more secretions she's got,

0:13:21.296,0:13:24.958
the more likely the baby is to suckle quickly.

0:13:24.958,0:13:26.418
If you're a mammal,

0:13:26.418,0:13:28.961
the most dangerous time in life

0:13:28.961,0:13:31.270
is the first few hours after birth.

0:13:31.270,0:13:35.030
You have to get that first drink of milk,

0:13:35.030,0:13:38.521
and if you don't get it, you won't survive.

0:13:38.521,0:13:39.985
You'll be dead.

0:13:39.985,0:13:42.623
Since many babies actually find it difficult

0:13:42.623,0:13:44.272
to take that first meal,

0:13:44.272,0:13:46.249
because they're not getting the right stimulus,

0:13:46.249,0:13:49.459
if we could identify what that molecule was,

0:13:49.459,0:13:51.446
and the French team are being very cautious,

0:13:51.446,0:13:53.561
but if we could identify the molecule,

0:13:53.561,0:13:56.355
synthesize it, it would then mean

0:13:56.355,0:13:58.261
premature babies would be more likely to suckle,

0:13:58.261,0:14:01.189
and every baby would have a better chance

0:14:01.189,0:14:02.510
of survival.

0:14:02.510,0:14:05.050
So what I want to argue is this is one example

0:14:05.050,0:14:08.646
of where a systematic, really scientific approach

0:14:08.646,0:14:11.368
can actually bring you a real understanding

0:14:11.368,0:14:12.476
of pheromones.

0:14:12.476,0:14:15.090
There could be all sorts of medical interventions.

0:14:15.090,0:14:16.344
There could be all sorts of things

0:14:16.344,0:14:18.044
that humans are doing with pheromones

0:14:18.044,0:14:20.092
that we simply don't know at the moment.

0:14:20.092,0:14:21.978
What we need to remember is pheromones

0:14:21.978,0:14:23.356
are not just about sex.

0:14:23.356,0:14:25.072
They're about all sorts of things to do

0:14:25.072,0:14:26.795
with a mammal's life.

0:14:26.795,0:14:29.484
So do go forward and do search for more.

0:14:29.484,0:14:30.524
There's lots to find.

0:14:30.524,0:14:32.390
Thank you very much.

0:14:32.390,0:14:36.878
(Applause)