0:00:00.940,0:00:03.918
"Pheromone" is a very powerful word.

0:00:03.918,0:00:08.852
It conjures up sex, abandon, loss of control,

0:00:08.852,0:00:12.444
and you can see, it's very important as a word.

0:00:12.444,0:00:17.517
But it's only 50 years old. It was invented in 1959.

0:00:17.517,0:00:20.116
Now, if you put that word into the web,

0:00:20.116,0:00:21.886
as you may have done,

0:00:21.886,0:00:24.418
you'll come up with millions of hits,

0:00:24.418,0:00:26.533
and almost all of those sites are trying to sell you

0:00:26.533,0:00:28.592
something to make you irresistible

0:00:28.592,0:00:31.865
for 10 dollars or more.

0:00:31.865,0:00:34.318
Now this is a very attractive idea,

0:00:34.318,0:00:36.530
and the molecules they mention

0:00:36.530,0:00:38.634
sound really science-y.

0:00:38.634,0:00:40.178
They've got lots of syllables.

0:00:40.178,0:00:43.171
It's things like androstenol and drostenome

0:00:43.171,0:00:45.342
or drostendienome.

0:00:45.342,0:00:47.164
It gets better and better,

0:00:47.164,0:00:49.774
and when you combine that with white lab coats,

0:00:49.774,0:00:51.226
you must imagine that there is

0:00:51.226,0:00:53.910
fantastic science behind this.

0:00:53.910,0:00:57.772
But sadly, these are fraudulent claims

0:00:57.772,0:01:02.351
supported by dodgy science.

0:01:02.351,0:01:04.949
The problem is that, although there are many

0:01:04.949,0:01:07.514
good scientists working on what they think

0:01:07.514,0:01:09.314
are human pheromones,

0:01:09.314,0:01:11.969
and they're publishing in respectable journals,

0:01:11.969,0:01:13.670
at the basis of this,

0:01:13.670,0:01:16.806
despite very sophisticated experiments,

0:01:16.806,0:01:19.439
there really is no good science behind it,

0:01:19.439,0:01:22.761
because it's based on a problem,

0:01:22.761,0:01:26.171
which is, nobody has systematically gone through

0:01:26.171,0:01:28.352
all the odors that humans produce,

0:01:28.352,0:01:31.059
and there are thousands of[br]molecules that we give off.

0:01:31.059,0:01:34.056
We're mammals. We produce a lot of smell.

0:01:34.056,0:01:36.144
Nobody has gone through systematically

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

0:01:38.911,0:01:40.621
They've just plucked a few,

0:01:40.621,0:01:42.660
and all these experiments are based on those,

0:01:42.660,0:01:45.570
but there's no good evidence at all.

0:01:45.570,0:01:47.888
Now, that's not to say

0:01:47.888,0:01:49.950
that smell is not important to people.

0:01:49.950,0:01:53.422
It is, and some people are real enthusiasts,

0:01:53.422,0:01:56.539
and one of these was Napoleon.

0:01:56.539,0:01:58.811
And famously, you may remember

0:01:58.811,0:02:01.668
that out on the campaign trail for war,

0:02:01.668,0:02:04.505
he wrote to his lover, Empress Josephine,

0:02:04.505,0:02:08.369
saying, "Don't wash, I'm coming home."

0:02:08.369,0:02:09.801
(Laughter)

0:02:09.801,0:02:11.602
So he didn't want to lose any of her richness

0:02:11.602,0:02:13.581
in the days before he'd get home,

0:02:13.581,0:02:16.328
and it is still, you'll find websites

0:02:16.328,0:02:19.860
that offer this as a major quirk.

0:02:19.860,0:02:21.394
At the same time, though,

0:02:21.394,0:02:23.397
we spend about as much money

0:02:23.397,0:02:25.328
taking the smells off us

0:02:25.328,0:02:27.969
as putting them back on in perfumes,

0:02:27.969,0:02:32.120
and perfumes are a multi-billion dollar business.

0:02:32.120,0:02:34.903
So what I want to do in the rest of this talk

0:02:34.903,0:02:40.121
is tell you about what pheromones really are,

0:02:40.121,0:02:43.189
tell you why I think we would expect

0:02:43.189,0:02:45.587
humans to have pheromones,

0:02:45.587,0:02:50.096
tell you about some of the[br]confusions in pheromones,

0:02:50.096,0:02:53.182
and then finally, I want to end with

0:02:53.182,0:02:55.182
a promising avenue which shows us

0:02:55.182,0:02:59.006
the way we ought to be going.

0:02:59.006,0:03:03.101
So the ancient Greeks knew

0:03:03.101,0:03:07.375
that dog sent invisible signals between each other.

0:03:07.375,0:03:09.659
A female dog in heat

0:03:09.659,0:03:11.515
sent an invisible signal to male dogs

0:03:11.515,0:03:13.360
for miles around,

0:03:13.360,0:03:15.365
and it wasn't a sound, it was a smell.

0:03:15.365,0:03:17.446
You could take the smell from the female dog,

0:03:17.446,0:03:19.989
and the dogs would chase the cloth.

0:03:19.989,0:03:21.327
But the problem for everybody

0:03:21.327,0:03:23.690
who could see this effect

0:03:23.690,0:03:25.332
was that you couldn't identify the molecules.

0:03:25.332,0:03:27.695
You couldn't demonstrate it was chemical.

0:03:27.695,0:03:29.042
The reason for that, of course,

0:03:29.042,0:03:30.785
is that each of these animals

0:03:30.785,0:03:32.371
produces tiny quantities,

0:03:32.371,0:03:34.014
and in the case of the dog,

0:03:34.014,0:03:36.492
males dogs can smell it, but we can't smell it.

0:03:36.492,0:03:40.770
And it was only in 1959 that a German team,

0:03:40.770,0:03:44.482
after spending 20 years in[br]search of these molecules,

0:03:44.482,0:03:48.303
discovered, identified, the first pheromone,

0:03:48.303,0:03:51.451
and this was the sex pheromone of a silk moth.

0:03:51.451,0:03:53.605
Now this was an inspired choice by Adolf Butenandt

0:03:53.605,0:03:55.166
and his team,

0:03:55.166,0:03:57.171
because he needed half a million moths

0:03:57.171,0:04:00.408
to get enough material to do the chemical analysis.

0:04:00.408,0:04:02.177
But he created the model

0:04:02.177,0:04:04.941
for how you should go about pheromone analysis.

0:04:04.941,0:04:07.562
He basically went through systematically,

0:04:07.562,0:04:10.267
showing that only the molecule in question

0:04:10.267,0:04:12.223
was the one that stimulated the males,

0:04:12.223,0:04:14.146
not all the others.

0:04:14.146,0:04:16.384
He analyzed it very carefully.

0:04:16.384,0:04:18.241
He synthesized the molecule,

0:04:18.241,0:04:21.189
and then tried the synthesized[br]molecule on the males

0:04:21.189,0:04:24.095
and got them to respond and showed it was,

0:04:24.095,0:04:26.083
indeed, that molecule.

0:04:26.083,0:04:28.043
That's closing the circle.

0:04:28.043,0:04:30.765
That's the thing which has[br]never been done with humans:

0:04:30.765,0:04:33.915
nothing systematic, no real demonstration.

0:04:33.915,0:04:36.109
With that new concept,

0:04:36.109,0:04:37.988
we needed a new word,

0:04:37.988,0:04:40.853
and that was the word "pheromone,"

0:04:40.853,0:04:44.254
and it's basically transferred excitement,

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

0:04:46.523,0:04:49.439
and since 1959, pheromones have been found

0:04:49.439,0:04:51.484
right the way across the animal kingdom,

0:04:51.484,0:04:53.646
in male animals, in female animals.

0:04:53.646,0:04:55.331
It works just as well underwater

0:04:55.331,0:04:57.243
for goldfish and lobsters.

0:04:57.243,0:04:59.130
And almost every mammal you can think of

0:04:59.130,0:05:00.933
has had a pheromone identified,

0:05:00.933,0:05:04.613
and of course, an enormous number of insects.

0:05:04.613,0:05:06.542
So we know that pheromones exist

0:05:06.542,0:05:08.743
right the way across the animal kingdom.

0:05:08.743,0:05:11.196
What about humans?

0:05:11.196,0:05:12.914
Well, the first thing, of course,

0:05:12.914,0:05:14.601
is that we're mammals,

0:05:14.601,0:05:16.280
and mammals are smelly.

0:05:16.280,0:05:17.956
As any dog owner can tell you,

0:05:17.956,0:05:19.767
we smell, they smell.

0:05:19.767,0:05:21.688
But the real reason we might think

0:05:21.688,0:05:23.623
that humans have pheromones

0:05:23.623,0:05:26.821
is the change that occurs as we grow up.

0:05:26.821,0:05:28.992
The smell of a room of teenagers

0:05:28.992,0:05:30.961
is quite different

0:05:30.961,0:05:33.301
from the smell of a room of small children.

0:05:33.301,0:05:36.503
What's changed? And of course, it's puberty.

0:05:36.503,0:05:38.112
Along with the pubic hair

0:05:38.112,0:05:39.765
and the hair in the armpits,

0:05:39.765,0:05:43.207
new glands start to secrete in those places,

0:05:43.207,0:05:45.852
and that's what's making the change in smell.

0:05:45.852,0:05:47.910
If we were any other kind of mammal,

0:05:47.910,0:05:49.509
or any other kind of animal,

0:05:49.509,0:05:50.936
we would say,

0:05:50.936,0:05:52.388
"That must be something to do with pheromones,"

0:05:52.388,0:05:54.434
and we'd start looking properly.

0:05:54.434,0:05:57.022
But there are some problems, and this is why,

0:05:57.022,0:05:59.969
I think, people have not looked for

0:05:59.969,0:06:02.646
pheromones so effectively in humans.

0:06:02.646,0:06:04.647
There are, indeed, problems.

0:06:04.647,0:06:06.651
And the first of these

0:06:06.651,0:06:08.428
is perhaps surprising.

0:06:08.428,0:06:09.992
It's all about culture.

0:06:09.992,0:06:11.899
Now moths don't learn a lot

0:06:11.899,0:06:15.716
about what is good to smell, but humans do,

0:06:15.716,0:06:17.842
and up to the age of about four,

0:06:17.842,0:06:20.261
any smell, no matter how rancid,

0:06:20.261,0:06:22.044
is simply interesting.

0:06:22.044,0:06:24.412
And I understand that the major role of parents

0:06:24.412,0:06:27.483
is to stop kids putting their fingers in poo,

0:06:27.483,0:06:30.411
because it's always something nice to smell.

0:06:30.411,0:06:33.242
But gradually we learn what's not good,

0:06:33.242,0:06:34.862
and one of the things we learn

0:06:34.862,0:06:36.797
at the same time as what is not good

0:06:36.797,0:06:38.725
is what is good.

0:06:38.725,0:06:40.927
Now, the cheese behind me

0:06:40.927,0:06:44.888
is a British, if not an English, delicacy.

0:06:44.888,0:06:48.205
It's ripe blue Stilton.

0:06:48.205,0:06:52.187
Liking it is incomprehensible to[br]people from other countries.

0:06:52.187,0:06:56.192
Every culture has its own special food

0:06:56.192,0:06:58.138
and national delicacy.

0:06:58.138,0:07:00.033
If you were to come from Iceland,

0:07:00.033,0:07:01.434
your national dish

0:07:01.434,0:07:04.066
is deep rotted shark.

0:07:04.066,0:07:06.640
Now, all of these things are acquired taste,

0:07:06.640,0:07:09.680
but they form almost a badge of identity.

0:07:09.680,0:07:14.078
You're part of the in group.

0:07:14.078,0:07:18.252
The second thing is the sense of smell.

0:07:18.252,0:07:21.751
Each of us has a unique odor world,

0:07:21.751,0:07:24.001
in the sense that what we smell.

0:07:24.001,0:07:26.889
We each smell a completely different world.

0:07:26.889,0:07:28.658
Now, smell was the hardest

0:07:28.658,0:07:30.499
of the senses to crack,

0:07:30.499,0:07:32.204
and the Nobel Prize awarded to

0:07:32.204,0:07:33.987
Richard Axel and Linda Buck

0:07:33.987,0:07:36.540
was only awarded in 2004

0:07:36.540,0:07:39.072
for their discovery of how smell works.

0:07:39.072,0:07:40.627
It's really hard,

0:07:40.627,0:07:43.338
but in essence, nerves from the brain

0:07:43.338,0:07:45.341
go up into the nose

0:07:45.341,0:07:47.892
and on these nerves, exposed in the nose

0:07:47.892,0:07:50.816
to the outside air, are receptors,

0:07:50.816,0:07:53.695
and odor molecules coming in on a sniff

0:07:53.695,0:07:55.645
interact with these receptors,

0:07:55.645,0:07:59.804
and if they bond, they send the nerve a signal

0:07:59.804,0:08:02.442
which goes back into the brain.

0:08:02.442,0:08:04.554
We don't just have one kind of receptor.

0:08:04.554,0:08:06.750
If you're a human, you have about 400

0:08:06.750,0:08:08.885
different kinds of receptors,

0:08:08.885,0:08:11.382
and the brain knows what you're smelling

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

0:08:13.193,0:08:15.916
and nerve cells that they trigger,

0:08:15.916,0:08:17.614
sending messages up to the brain

0:08:17.614,0:08:20.078
in a combinatorial fashion.

0:08:20.078,0:08:21.470
But it's a bit more complicated,

0:08:21.470,0:08:23.295
because each of those 400

0:08:23.295,0:08:25.836
comes in various variants,

0:08:25.836,0:08:27.807
and depending which variant you have,

0:08:27.807,0:08:31.699
you might smell coriander, or cilantro, that herb,

0:08:31.699,0:08:34.367
either as something delicious and savory

0:08:34.367,0:08:36.491
or something like soap.

0:08:36.491,0:08:39.517
So we each have an individual world of smell,

0:08:39.517,0:08:41.238
and that complicates anything

0:08:41.238,0:08:43.274
when we're studying smell.

0:08:43.274,0:08:45.906
Well, we really ought to talk about armpits,

0:08:45.906,0:08:49.462
and I have to say that I do[br]have particularly good ones.

0:08:49.462,0:08:51.554
Now, I'm not going to share them with you,

0:08:51.554,0:08:53.343
but this is the place that most people

0:08:53.343,0:08:55.071
have looked for pheromones.

0:08:55.071,0:08:56.673
There is one good reason,

0:08:56.673,0:08:59.997
which is, the great apes have armpits

0:08:59.997,0:09:02.455
as their unique characteristic.

0:09:02.455,0:09:04.686
The other primates have scent glands

0:09:04.686,0:09:06.426
in other parts of the body.

0:09:06.426,0:09:08.910
The great apes have these armpits

0:09:08.910,0:09:11.117
full of secretory glands

0:09:11.117,0:09:13.728
producing smells all the time,

0:09:13.728,0:09:17.248
enormous numbers of molecules.

0:09:17.248,0:09:18.981
When they're secreted from the glands,

0:09:18.981,0:09:20.995
the molecules are odorless.

0:09:20.995,0:09:22.780
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

0:09:26.962,0:09:28.618
that actually produces the smells

0:09:28.618,0:09:30.679
that we know and love.

0:09:30.679,0:09:32.339
And so incidentally, if you want to reduce

0:09:32.339,0:09:33.969
the amount of smell,

0:09:33.969,0:09:35.909
clear-cutting your armpits

0:09:35.909,0:09:37.945
is a very effective way of reducing

0:09:37.945,0:09:39.629
the habitat for the bacteria,

0:09:39.629,0:09:41.796
and you'll find they remain less smelly

0:09:41.796,0:09:43.750
for much longer.

0:09:43.750,0:09:46.436
But although we've focused on armpits,

0:09:46.436,0:09:47.853
I think it's partly because they're the least

0:09:47.853,0:09:50.178
embarrassing place to go and ask people

0:09:50.178,0:09:51.850
for samples.

0:09:51.850,0:09:54.322
There is actually another reason why we might not

0:09:54.322,0:09:57.158
be looking for a universal sex pheromone there,

0:09:57.158,0:10:00.777
and that's because 20 percent[br]of the world's population

0:10:00.777,0:10:04.662
doesn't have smelly armpits like me.

0:10:04.662,0:10:08.568
And these are people from China, Japan,

0:10:08.568,0:10:11.353
Korea, and other parts of northeast Asia.

0:10:11.353,0:10:14.677
They simply don't secrete those odorless precursors

0:10:14.677,0:10:18.730
that the bacteria love to use to produce the smells

0:10:18.730,0:10:21.429
that in an ethnocentric way we always thought of

0:10:21.429,0:10:23.544
as characteristic of armpits.

0:10:23.544,0:10:27.971
So it doesn't apply to 20 percent of the world.

0:10:27.971,0:10:30.483
So what should we be doing

0:10:30.483,0:10:33.746
in our search for human pheromones?

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

0:10:36.198,0:10:38.231
We're mammals, like everybody else

0:10:38.231,0:10:42.036
who's a mammal, and we probably do have them.

0:10:42.036,0:10:43.713
But what I think we should do

0:10:43.713,0:10:45.512
is go right back to the beginning,

0:10:45.512,0:10:48.201
and basically look all over the body.

0:10:48.201,0:10:49.832
No matter how embarrassing,

0:10:49.832,0:10:53.079
we need to search and go for the first time

0:10:53.079,0:10:55.310
where no one else has dared tread.

0:10:55.310,0:10:56.978
It's going to be difficult.

0:10:56.978,0:10:59.653
It's going to be embarrassing, but we need to look.

0:10:59.653,0:11:02.083
We also need to go back to the ideas

0:11:02.083,0:11:05.787
that Butenandt used when he[br]was studying the silk moth.

0:11:05.787,0:11:08.925
We need to go back and look systematically

0:11:08.925,0:11:11.493
at all the molecules that are being produced,

0:11:11.493,0:11:13.816
and work out which ones are really involved.

0:11:13.816,0:11:15.602
It isn't good enough simply to pluck a couple

0:11:15.602,0:11:17.936
and say, "They'll do."

0:11:17.936,0:11:19.485
We have to actually demonstrate

0:11:19.485,0:11:22.275
that they really have the effects we claim.

0:11:22.275,0:11:25.429
There is one team that I'm[br]actually very impressed by.

0:11:25.429,0:11:28.425
They're in France, and their previous success

0:11:28.425,0:11:32.652
was identifying the rabbit memory pheromone.

0:11:32.652,0:11:35.271
They've turned their attention now

0:11:35.271,0:11:38.656
to human babies and mothers.

0:11:38.656,0:11:41.667
So this is a baby having a drink of milk

0:11:41.667,0:11:44.490
from its mother's breast.

0:11:44.490,0:11:46.113
Her nipple is completely hidden

0:11:46.113,0:11:47.899
by the baby's head,

0:11:47.899,0:11:51.510
but what you'll notice is a white droplet

0:11:51.510,0:11:53.141
with an arrow pointing to it,

0:11:53.141,0:11:56.310
and that's the secretion from the areolar glands.

0:11:56.310,0:11:59.084
Now, we all have them, men and women,

0:11:59.084,0:12:02.298
and these are the little bumps around the nipple,

0:12:02.298,0:12:04.177
and if you're a lactating woman,

0:12:04.177,0:12:06.274
these start to secrete.

0:12:06.274,0:12:09.183
It's a very interesting secretion.

0:12:09.183,0:12:12.296
What Benoist Schaal and his team developed

0:12:12.296,0:12:14.643
was a simple test to investigate

0:12:14.643,0:12:17.269
what the effect of this secretion might be,

0:12:17.269,0:12:20.315
in effect, a simple bioassay.

0:12:20.315,0:12:22.880
So this is a sleeping baby,

0:12:22.880,0:12:27.929
and under its nose, we've put a clean glass rod.

0:12:27.929,0:12:30.021
The baby remains sleeping,

0:12:30.021,0:12:32.481
showing no interest at all.

0:12:32.481,0:12:34.475
But if we go to any mother

0:12:34.475,0:12:36.954
who is secreting from the areolar glands,

0:12:36.954,0:12:38.461
so it's not about recognition,

0:12:38.461,0:12:40.719
it can be from any mother,

0:12:40.719,0:12:42.231
if we take the secretion

0:12:42.231,0:12:45.185
and now put it under the baby's nose,

0:12:45.185,0:12:47.176
we get a very different reaction.

0:12:47.176,0:12:50.008
It's a connoisseur's reaction of delight,

0:12:50.008,0:12:52.047
and it opens its mouth

0:12:52.047,0:12:53.723
and sticks out its tongue

0:12:53.723,0:12:55.860
and starts to suck.

0:12:55.860,0:12:58.045
Now, since this is from any mother,

0:12:58.045,0:13:00.102
it could really be a pheromone.

0:13:00.102,0:13:01.861
It's not about individual recognition.

0:13:01.861,0:13:03.577
Any mother will do.

0:13:03.577,0:13:05.092
Now, why is this important,

0:13:05.092,0:13:07.308
apart from being simply very interesting?

0:13:07.308,0:13:09.475
It's because women vary

0:13:09.475,0:13:12.248
in the number of areolar glands that they have,

0:13:12.248,0:13:14.204
and there is a correlation between the ease

0:13:14.204,0:13:16.636
with which babies start to suckle

0:13:16.636,0:13:18.938
and the number of areolar glands she has.

0:13:18.938,0:13:21.696
It appears that the more secretions she's got,

0:13:21.696,0:13:24.878
the more likely the baby is to suckle quickly.

0:13:24.878,0:13:26.758
If you're a mammal,

0:13:26.758,0:13:29.121
the most dangerous time in life

0:13:29.121,0:13:31.750
is the first few hours after birth.

0:13:31.750,0:13:35.035
You have to get that first drink of milk,

0:13:35.035,0:13:38.821
and if you don't get it, you won't survive.

0:13:38.821,0:13:40.325
You'll be dead.

0:13:40.325,0:13:42.653
Since many babies actually find it difficult

0:13:42.653,0:13:44.442
to take that first meal,

0:13:44.442,0:13:46.589
because they're not getting the right stimulus,

0:13:46.589,0:13:49.459
if we could identify what that molecule was,

0:13:49.459,0:13:51.596
and the French team are being very cautious,

0:13:51.596,0:13:53.801
but if we could identify the molecule,

0:13:53.801,0:13:56.355
synthesize it, it would then mean

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

0:13:58.261,0:14:01.479
and every baby would have a better chance

0:14:01.479,0:14:03.140
of survival.

0:14:03.140,0:14:05.058
So what I want to argue is this is one example

0:14:05.058,0:14:08.236
of where a systematic, really scientific approach

0:14:08.236,0:14:11.198
can actually bring you a real understanding

0:14:11.198,0:14:12.706
of pheromones.

0:14:12.706,0:14:15.065
There could be all sorts of medical interventions.

0:14:15.065,0:14:16.574
There could be all sorts of things

0:14:16.574,0:14:18.104
that humans are doing with pheromones

0:14:18.104,0:14:20.372
that we simply don't know at the moment.

0:14:20.372,0:14:21.978
What we need to remember is pheromones

0:14:21.978,0:14:23.516
are not just about sex.

0:14:23.516,0:14:25.422
They're about all sorts of things to do

0:14:25.422,0:14:26.955
with a mammal's life.

0:14:26.955,0:14:29.604
So do go forward and do search for more.

0:14:29.604,0:14:30.994
There's lots to find.

0:14:30.994,0:14:33.097
Thank you very much.

0:14:33.097,0:14:36.878
(Applause)