This video is sponsored by Pandacraft. These are experiment kits for children,
more information at the end of the video. Every time I catch up on the dishes of the month,
it's always the same thing. My fingers end up all wrinkled, although (luckily),
I have clean dishes by the end of it. So, I know that it's because I put my hands
in hot water that my skin gets wrinkly… but how does that happen?
What is the mechanism behind it? How come my skin ends up looking like a dry prune when I'm
wetting it? It's not dry at all. But above all, an existential question... are my dishwashing skills better
when I have wrinkly skin than when I don't?
I know, it sounds stupid as a question. First off because I have a dishwasher and this whole thing was
just a setup... but also because there is no clear link
between dishes and wrinkly skin. And yet. There is research
that looks at grip, our ability to grab things (wet dishes, for example)
when we have wrinkled skin and when we don't. The idea being
to find out whether this wrinkled skin might not be some sort of evolutionary advantage that we would
have kept over time. So, in your opinion, are we evolutionarily built to do the dishes?
I know a few of you are wondering; and no, I am not deep squatting.
I still can't do it.
You don't know it, but the topic of this video
comes from you. A few months ago, I made a video about dry skin.
And during the conversation with Dermatodrey who was my guest, it was said that
wrinkled skin was related to the presence of water. "Besides, when you are in the bath,
after a while you see that your skin has changed because your fingers are
all wrinkled." That was off topic so we didn’t get any further than that.
But in the comments, several of you wrote to tell me that that was wrong, and that it was more
complicated than that. So I researched a bit and indeed, it is much more complicated than that.
However, the statement wasn't technically wrong, but it was only 10%
of the story. So today, we are looking at the remaining 90% of the story.
Here is what we know for sure. We know it takes rather hot water for this
to happen. We also know that this does not happen everywhere on the human body: the skin must be
glabrous, that is to say hairless, and it must feature sweat glands.
For example, the penis and the clitoris are glabrous areas without hair
but without a sweat gland... we do not get this phenomenon of wrinkled skin. These two conditions mean that
it leaves us with only the hands and feet as potentially affected areas… And by the way,
this also may indicate that something's up with the sweat glands,
if we absolutely need to have sweat glands for this to happen.
We also know (and this is where it gets sexy for many researchers working
in this field), that if we have a nervous problem, specifically at the level of the
autonomic nervous system... the skin, even if left soaking in water, will not wrinkle. The fact that it's linked
to the nervous system, we've known since the 1930s, so it's been a while.
And it is even sometimes used to find out if the patient has nerve damage.
Soak the patient's hands in hot water, wait 30 min. If the skin has wrinkled,
everything is fine. Otherwise... there may be a problem with their nervous system.
In reality it is not that binary, there are stages of "finger wrinkling" that make this test
more complex than I made it sound. From these 3 certainties and lots of
observational, anatomical clues, a certain Mr. Wilder-Smith came up with an explanation for
how the skin wrinkles. From what I understand, this is the most up-to-date explanation we have today
(although the article is 18 years old). I'll share it with you, but if you could stay focused
for about 2 minutes, that would be great. The skin of our fingers
features lots of conduits through which perspiration normally exits. Moreover,
it is in our hands that we have the greatest concentration of these conduits on the body.
Which technically makes it the most porous part of the body. It turns out that if we soak in water
long enough, these conduits end up filling up with this outside water
(not our own perspiration but the outside water). You might think, 'well this is it then,
the skin swells in some places because it drinks up the outside water, and that's what creates the relief
in our fingers, end of story ”… Not at all friends, not at all! It is even rather the opposite! In fact,
the water that enters the ducts does not have the same ions as inside our body.
That creates an electrical imbalance between the inside of the conduits and our body,
which is all around them. The complicated word to express this imbalance is dyselectrolyteemia (I wanted
to say it because I had to practise saying it). Dyselectrolytemia. And it turns out,
you might know it already, but our body is a big electrochemical machine.
We have plenty of sodium, potassium, chlorine, contraption, stuff, things… there are plenty of them
and they are key to our functioning. Among other things, they trigger
muscle contractions, which help transport fluids... a lot of things in fact... And which
also play a part, and this is what interests us, in nerve impulses. This is the link that
we will see in a few moments. In short, having ions, electric charges, the balance
of all of that is important to make our body function. Except that... The water that shows up in our
perspiration droplets would disrupt this balance. This disturbance would lead
to involuntary nerve activation. I don't go into more detail on what the modified ions would be,
nor exactly how the nerve impulse would be triggered — because the article
itself does not. So we have a nervous activation. But it turns out that the nerves that
are close to the ducts, most are there to regulate our temperature, that is to say, to ensure
the vasodilation or vasoconstriction of our blood vessels. That is to say, controlling
the diameter of our blood vessels. If it's wide open, it's dilated, if it's tiny
it's constricted... aka small. Right. We still have to make the connection between
vasoconstriction and the appearance of wrinkles in the skin. In fact, we are missing a structure
of the skin that you may not know (at least I did not know it
before I got interested in this subject): neurovascular glomus. It's a lump that contains
lots of arterioles, and is connected, with connective tissue, to the rest of the skin.
Now is the end of the story. If there is vasoconstriction, it means that
there is less blood volume in the ball (the glomus), and it then becomes smaller.
And as it decreases in size, it pulls on the skin to create a valley. Badabim, badaboum,
this is how wrinkled skin is formed. Those lumps or glomus of blood vessels that
constrict and pull the blanket over them, so to speak. Quick side note for those of you who follow this
video series. If you remember, in the video where we talked about sticking your foot
out of the quilt to regulate your temperature at night... we
discovered a key thing called arteriovenous anastomoses. I'd called them Ana's.
Well the glomus are arteriovenous anastomoses, Ana's,
but in the form of a ball… the circle is complete. I invite you to watch or
rewatch that video because these two subjects are really connected. End of the aside.
So our current hypothesis is that water would enter the ducts,
which would produce an electrical imbalance, which would in turn activate the nerves in the area.
And we know that wrinkled skin and the nervous system are connected. These nerves create
vasoconstriction of the neurovascular glomus, which by reducing in size would pull on the skin above,
thus creating wrinkles in the skin. And so? Now that we know the how of it,
the question of why comes pretty quickly. Have we evolved to do
the dishes without our plates slipping from our fingers? Of course not. I'm joking!
But the joke highlights a more legitimate question. Couldn't the wrinkled skin
have helped us, at one time, to have a better grip for picking,
hunting, escaping... in a humid environment. To find out, the first step is to check
whether our grip is actually better with wrinkled fingers than without. Here is
a 2012 study, which asked 20 participants to pass 45 objects around, beads like this,
under 3 conditions: with dry hands, with wet but not wrinkled hands, and with
wet and wrinkled hands. The goal was to transfer objects as quickly as possible from one hand to the other
using only the thumb and forefinger. And what they found was that the time it took
for participants to transfer objects with dry hands or wrinkled hands was not much different.
But with wet and not wrinkled hands, it took 17% more time.
So that means there was an advantage with wrinkled hands, since they went
ster with wrinkled hands than with wet, non-wrinkled hands. And so that would allow us
to move faster in a wet environment. One point for the adaptive hypothesis. I reproduced the experiment myself.
Out of curiosity, because it amuses me, but also (in all honesty) because I don't really believe
these results or this hypothesis. And I wanted to see what it looked like.
I did two tests for each condition, roughly the same experimental conditions. I had about
40 objects and I took an average of 50.5 seconds when my hands were dry,
55.4s when my hands were wet but not wrinkled and 51.32s when my hands were wrinkled.
So the whole thing does not give us a scientific result that we can really compare
to the article; there are few repetitions, I am alone... There are many issues in my work here.
That's not really the point. But still, my results are more in favor of the article, with
this tendency to have a better grip with wrinkled fingers. Then again, I did not
particularly feel any difference during my tests.
My experiment doesn't say much, I would tend to trust the literature
that has been published on the subject more. But the point is, I had doubts that did not come
out of nowhere. Particularly because two years after the publication of this article, another team
replicated the experiment, with twice as many participants. And they published it with almost the same
article title but the opposite conclusion (honestly that's a pretty provocative move).
They concluded that wrinkled skin didn't change much, according to this study with
twice as many participants. Scientists battle!! And it's not over. 2021, this year.
New article. New drama. This one concludes that yes, like the first article, wrinkled skin seems to
improve grip. Published again with the same title structure just to
rub salt in the wound. This time it's a new experiment, it's not about
passing objects around, it's a little more complicated. But above all it was done with 546 participants.
Enough to put the other two studies to shame with their 20 and 40 participants. So did this article
just knock out the previous two? Do we finally have a definitive answer?
A conclusion as to why we get wrinkly skin? Well no, not really. Because
that too, the battle of scientists, is also for show — like the dishes at the start of the video.
The scientific process is to seek, sometimes to find something positive,
a conclusion; then sometimes to find another conclusion... This is what keeps us
moving forward and evolving. That's normal, it's part of the process. So when do we know we've reached the end?
Personally, after reading these articles and their limits too, I think we will have to
wait a little longer to have an answer that generates consensus in the scientific community,
both on exactly the mechanism of wrinkle formation (because you've seen it, not everything
has been proven), and whether evolution has something to do with it. Besides, here's something I couldn't
get out of my head while I was doing research for this video. Why would we
want there to be an evolutionary reason for this phenomenon? Let me give you
my reasons for questioning this. Then I'll turn it over to someone who
knows more about it than me, Pierre Kerner. First, my reasons. I have 2 problems
with looking for an evolutionary reason. First, I know that our “ancestors” often are a
convenient scapegoat to justify our behavior. And in general, we’re wrong
so I know we have to be careful about that stuff. So this is my first reason.
Second reason, more technical. In order toget wrinkled skin, you don't need a humid
environment... you need to be soaking in water — hot water.
Can it possibly work with cooler water if you are submerged long enough?
I have tested for you (despite myself, believe me). I soaked my feet in cold water
for hours on a bike, and… “No! I don't have wrinkled skin!" Yay for summer…!
And it doesn't seem to me that was the case with hunter-gatherers. Seems weird, doesn't it?
Pierre: Your red flags seem to me to be absolutely justified and relevant.
Phew! Pierre: So, for me,
my first instinct when I heard you tell me about it was: if the autonomic nervous system
which is involved in the phenomenon, that characteristic is a little more
complicated than a passive thing like: your heart is pumping, therefore you hear noise — that's passive,
there is no function to hearing your own heartbeat. So I also thought,
the autonomic nervous system on the fingertips is particularly developed.
So I thought, it's not impossible. Then after rereading your script more carefully,
we've got a phenomenon which, potentially, is only passive.
Doubts are allowed. So, I am less critical than you, but in any case quite titillated.
Well. I conclude that I may be exaggerating a bit and that there is a legitimate reason to investigate
whether or not there is an evolutionary reason. There you go, now you know that we partially understand the phenomenon
behind how our skin gets shriveled up. As for the why it occurs,
whether there is an adaptive reason... which we don't know... we will have to wait
a few more years for a consensus to be reached. Thanks to you for bringing up this video topic
which turned out to be more interesting than it looks. And interestingly, I suggest
you stay for the commercial break because... I think the sponsor is really cool, actually.
This video is sponsored by Pandacraft. These are kits for children between 3 and 12 years old that
are focused on discovery. For example, for the month of September 2021, the theme was
teeth. They sent me the kit this month, as a follow-up to my toothbrush video
if you remember it from a few months ago. But it changes every month,
October will be about forests, November will be about painting, December will be about Greek mythology, etc.
So it's all about discovery and there are lots of different themes. I completed the kit for
3-7 year olds and I have to say that I could do it very easily even though I'm barely
over the age range. Each experience is accompanied by visual explanations,
you have all the details, you can also go and get a video to explain the assembly,
so that makes it accessible to everyone. It also comes with an educational magazine that goes into
not only the activity, so this time it was a whole dossier on teeth, but
also other subjects like in any magazine that one would buy at a newsagents'. For the 8-12 year old kit,
this was it. It's the same principle but you immediately see the difference. You need more
meticulousness to put it together, the magazine is also much more thorough with a lot more
topics covered, it goes more in depth, etc. And frankly, I find these to be
great weekend activities. This is the kind of kit I wish I had as a kid.
And also clearly the kind of business where I would see myself working if I didn't do
what you see me doing today. It's very cool. Besides, in a way
I'm already doing it. Do I have it… Yes! Do you remember Clac? This is the 12 years++ version
that I made for the toothbrush video, in fact. These kits
are monthly subscriptions. If you use the link in the description, and you use the
promo code scilabus, you will get 10% off subscriptions and gift cards.
I love this kind of product, this kind of models... Pandacraft, I'm happy to collab again
whenever you want. Go see the link in the description whether for your own children, your friends'
children, your nephews, nieces... to get 10% off. I hope you like it.