I want to talk to you today about the evolution of the brain.
And in particular of course, the evolution of the human
brain, although we will talk about some other brains as well.
You may recall from way back in the beginning of the course when I talked to
you first about Darwin and his whole saga of trying
to figure out when and how to publish his big idea about evolution.
And the one thing that made him wait to publish that more than anything else
was his realization that he couldn't leave the brain out of that formula.
That it was a, a also a product of this same evolutionary process.
Here's a quote from
one of his books, he says, why is thought being a secretion of the brain?
I love that, secretion of the brain.
But why is though being a secretion of the
brain more wonderful than gravity, the property of matter.
It's our arrogance and our admiration of ourselves.
He said that it's just the way things are.
And it's,
no more or less factual than the information that we have about
gravity and the planets and all the other physical, chemical sciences.
But, it's a difficult concept for people
to deal with. And we've talked about this several times
already during the course. And, there seems to be a great
need for something else. There seems to be a, a
great need to have some sort of a spiritual non-physical
element to go along with it that we don't all always
see the richness of just the biological
fact of our brains and, and how they work. I want to
begin by giving
you, I don't think Dennant calls it this but I call it
Dennant's creed.
He has written probably his most famous book relating to this course.
That would be his book called Breaking the Spell.
Where he really delves into great philosophical detail and he's, I, I have
to say, one of the very few philosophers that I find easy to read.
He really does have a, a sharp mind and a really good way of presenting
the information. But he deals with this throughout the book
but the one quote that really caught my attention was his response
to the question well how can, how can we live a, a good life and a rewarding life.
If we don't believe in these non-physical types of things.
And this is what he said.
I'm going to read it as well.
He said, if you can approach the world's
complexities, both its glories and its horrors, with an
attitude of humble curiosity, Acknowledging that however deeply you
have seen you have only just scratched the surface.
You will find worlds within worlds, beauties you could
not heretofore imagine, and your own mundane preoccupations will sink
to proper size. He means small there.
For if you can stay centered and engaged,
you will find the hard choices easier, the right
words will come to you when you need them, and you will indeed be a better person.
That, I propose, is the secret to spirituality, and it has nothing at
all to do with believing in an immortal soul, or in anything supernatural.
So that's kind of his central point.
It's his rock in the stream, where all the other ideas flow
around it, and he de, he defends that rock very vigorously in, in his
writings and as you've seen in, in his discussions on videos and everything.
So he's done a lot of thinking. About this and a lot of thinking about,
how we can survive quite nicely in a world
where we understand how the world works around it.
And this has certainly been something that's been in the news recently.
Relating to the election and in some very real sense.
A lot of the things that happened in the
past election was kind of a return to some evidence
based thinking about these things, and kind of
a rejection of some of the anti science things.
Certainly a lot of other things were involved as
well but that's one of the things that have
been a recurring topic in the post-election analysis, and
we're all sick of election and post-election by now.
But it's an important, national discussion that we have.
Well, what I want to do today is to scratch the surface a little bit.
The brain evolution and try to walk you through what seem
to be some of the important aspects of human brain evolution.
And here's what we're going to do. We're going to
talk about three sort of major themes as we go through the lecture.
And Professor Solomon has talked about this.
I've talked about it a little.
About kind of the mediocrity of the physical human being.
We're not very fast compared to a lot of animals.
Our visual system,
although pretty good, and probably one of our, our best, sensory
systems does not compare favorably
with the visual system of an eagle auditory system and
so on and so forth. We're just always kind of in the middle,
and it's very easy to go out and find another species that can best us in almost
any aspect of our behavior or our abilities to perceive the world around us.
But what we're going to see is how the evolution of the human brain has
given us leverage of the systems and in some sense,
we'll see that our sensory systems have given up, in a way,
some of their basic capabilities out in the periphery.
In exchange for the much more powerful interpretation centered within the brain.
Professor Ogilvie talked awhile back about the
progressive emergence of more and more complicated selfs.
I struggled for awhile about whether to call it selfs or selves.
Just kind of like people have struggled with whether that thing you use
for the computer, if you have one of them, are they mouses or mice?
And I think they finally decided that they're supposed to be mouses.
So that gave me the courage to call them selfs.
But we'll see that human evolution has
given us the time that is needed for these very complex things to develop.
so, one of the things we're going to be talking about is the very long childhood.
That humans have.
That give us the opportunity to develop the
selfs and a lot of other things as well.
Professor Ogilvy also talked about the power of cuteness a while back.
And strangely enough we're going to see that
cuteness Is also an important theme of human evolution.
And the particular thing that we'll be talking
about is something that is known as neoteny.
Neoteny,
N-E-O-T-E-N-Y.
So let's start out by looking at some
of the results of evolutionary processes in, in other creatures.
I'm going to show you several different creatures and, and ask you to give me some
ideas about what you think are the special adaptations for these creatures.
So let's begin with the muskrat.
What's special adaptation that the muskrat might have?
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Yes?
>> Being able to blend in with its surroundings like its [CROSSTALK].
>> Okay, blending in with its
surrounding, A special camoflage, that works.
Anything else? >> Ability to swim.
That's good if you're going to be
a muskrat and, and they're, they're great swimmers.
So, so, a couple of examples there. Okay, let's move onto the squirrel.
Adaptations of the squirrel.
C'mon guys, you can do it. >> Able to climb trees.
Able to climb trees, yes.
They like store nuts in their like mouths [INAUDIBLE].
Yeah, they, they can store nuts and then they take them off and, and bury then and.
Mabey even remember where they buried them after that so yes.
>> [INAUDIBLE]. >> They're not very good at that.
[LAUGH] Mallard duck.
Yes?
>> [INAUDIBLE] those webbed feet.
>> Webbed feet for swimming.
Feathers to keep them warm feathers are actually kind of oily
to so their, their well adaptive to the water way back there.
>> Can they fly?
>> They can fly yes. Affliated Woodpecker.
>> Sharp beck. >> Sharp beak.
Anything else?
Actually the pileated woodpecker is kind of cool.
They have special muscle structures so they don't get
concussions when they're pecking on the, on the tree.
The egret.
Anybody have a, okay go ahead.
Long neck, that's good for giving it perspective.
Alex? Long legs, good for wading in the water.
I saw one a while back, a few years ago. Wading out into a river and it waded
into some deep water and swam away, and I was shocked.
I had never even considered whether they can swim or not.
But obviously
you have to be able to swim if you spend your life wading around in water.
Here's one that you may not know
what do you think the special adaptations of the woodcock might be?
Yes? >> Camouflage?
>> Camouflage. They're awfully hard to see.
Anything else?
Notice, might even be hard to see because of
camouflage, but its beak starts here and ends here.
Big long beak. They stick that down in the ground
and bring up worms and larvae and things like that as a part of their
diet. So all very good ideas
and things about special adaptations but you
missed the big one. You missed the big adaptation
that they all have in common.
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Brains. Of course they have to have brains.
But, each one of these creatures
with their sometimes amazing physical adaptations.
Those physical adaptations wouldn't be worth squat if they didn't have some
special area in their brain, that controlled the
behavior associated with that adaptation.
So the squirrel has to be able to be able to find nuts and, and store them and
all of these other creatures have to have specialized
brain areas that allow them to use these physical adaptations.
So this is a coordinated thing that
happens, that,uh, we don't just have physical adaptation
going on and behavioral adaptation going on.
They work very much hand in hand in the evolutionary process, and what
we're going to see is that human brain evolution is especially good at that.
So, behavior is often overlooked, but
it's probably the single most important adaptation
that any complicated creatures might have. So
we're going to be talking a little bit about building a brain.
And, for all of his fussing and franting
about it Charles Darwin didn't even really mention the
brain and behavior until the very end of The
Origin of Species where he gave it one sentence.
And he said, psychology will be securely
based on the necessary acquirement of each mental
power and capacity by gradation.
Not that different from what he was talking about physcailly but he's saying
that we have to have the evolution of all the individual components
of behavior that ultimatley go into the huge complexity of human behavior.
Hundred years or so later couple of other neuroscientists had
a long and complicated article in, in a review journal.
And one of the things that they said was the main neuronal circuits achieve an
architecture that is breathtaking in its complexity, but frugal in its variability.
Breathtaking in its complexity, but frugal in its variability.
So the breathtaking in complexity part We'll spend a bit of time on.
The brain is just an amazingly complicated
structure and whether you're looking at it with
the naked eye and then with the dissecting scope and then with a regular microscope.
And eventually electron microscope you just keep seeing more and
more complexity as you delve into the structure of the brain.
The frugal invariability part means essentially that
we can have the discipline of neuroanatomy.
So your brain looks a lot like my brain and both of
those brains look a lot like this plastic model of a brain here.
And in the same way that it's possible to look at a skeleton and name
the bones of the skeleton. You can then look at somebody
else's bones, and it will be easy to apply those labels to somebody else's skeleton.
And the same thing is true of brains that there's a
commonality amongst brains so that you can go
in and label the hippocampus, and the amygdala, and all sorts of other
Latin name structures within the brain and
apply those same names to somebody else's brain.
But, as we'll see, when you look at the details
of the brain, if we went in and looked at the
substructure of the individual connections within the brain, then your brain
would not look like my brain, and you would probably be
grateful for that because if your brain looked exactly
like my brain, you would think like I do.
And how bad would that be?
Pretty bad.
So how do we go about building a human brain?
Like everything else, it starts out with a blueprint.
And that blueprint of course is the, DNA
and that provides the building instructions for the brain.
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Mostly the building and structures, building instructions for
the frugal in variability part of the brain.
It's just building the basic structure of the brain.
And when we look at the embryology of the developing human.
We see just how important this building of the brain is.
Of course you all know that we start out with a mommy and a daddy
loving each other very much and all that kind of stuff, and we end up then with.
The cells coming together, and they begin to divide,
multiply, and after a fairly
short period of time, you end up with a little ball of cells that
looks a lot like a tiny little soccer ball.
It's something that you would probably not quite
be able to quite see with the naked eye.
You'd probably need at least a dissecting microscope to see that.
But already important things are beginning to happen.
And if you were to take a soccer ball that didn't have quite enough air in it.
And give it a little karate
chop, it would make a groove on the top
of the soccer ball, and that's pretty much what
the human embryo looks like in the very, very
early stages, where you could quite literally count the cells.
Have a little groove, like that.
And, this groove is called the neural groove, because that is the beginning
of the development of the brain.
So the absolute first thing that happens to distinguish the embryo to give
it some structure beyond just a little ball of cells is the nervous system.
The brain that's starting.
A little bit later the groove gets deeper. A little bit later than that,
it actually forms a tube called the neural tube, and that
is then the number of cells that are going to form the brain and the spinal cord.
Coming over here to this part of the
diagram you see kind of a schematic of the brain.
And that tube begins to fold over and get bumps on
it and become more and more complicated and sending things out.
And that's going to eventually form a very complicated bump.
The human brain at the top end of it and all the other fibers that go out
to serve the body.
So the nervous system takes precedence in all of this.
And at the stage of development where you already have a fairly complicated
brain beginning to develop, the rest of the embryo is not developed.
There might be tiny little bumps here and
here, and here and here where arms and legs
are just barely beginning to develop. But not, not much else.
So basically starts at the brain and develops everything else.
From that.