Biology 1350 Science of Perception

>>Susan Fisher: Well, we’re back.

And we’re going to begin what may strike you as a diversion from our intended goal

of learning about the biology of hope and belief.

But alas, it turns out if you’re going to understand either one,

we have to have a little bit of information of how humans process information

and thought. And to do that we need

to know something about the nervous system.

Now, if you are, perchance, a psychology major, you’ve had all of this stuff.

In fact, you can probably safely ignore a lot of what I’m going to say.

But for the rest of you, particularly those who have not had grounding in biology,

we’re going to spend a total of three modules talking about this.

And for some of you this will be the most difficult part of the course.

But I promise to tone it down and not ask of you things

that we would ask of a biology major.

For instance, you will not be asked solve a problem with the Nernst equation.

For instance, we are really going to focus on the big picture here.

But we do need to know something about the nervous system

and how it’s set up and how it functions

in order to get a grip on those issues that are relevant to this course.

So I’m going to promise you something I cannot deliver.

Namely, that talking about the nervous system and the ability to perceive things

in the real world will lead us to an understanding of those ineffable things

like the mind, the body, the spirit, the soul, all that stuff.

Nobody can really tell you what that means.

At least we can talk about it with some greater degree of clarity

if we first talk about the nervous system.

So that’s why we are going to do this.

And again, for those of you who take part in these conversations

of these modules and of the words and find it to be mind boggling and scary.

Don’t worry. You’re going to have three of these to get through.

Once you get through them, you’re more or less done with it except the final exam.

And so it will be a breeze from here on out.

But I like to get these more difficult presentations out of the way upfront

so that once you’re done with this you’ve got free sailing.

It’s like no big deal.

So with that in mind, let’s get started.

This is a presentation broken up for you in four convenient parts.

During the first of which, we’re going to talk about the classic Robot Experiments.

It’s an actual experiment done by actual scientists and this teaches us

a lot about the differences between those things that have a brain

and those things that do not.

So, we’ll start with that and then we’ll go on to talk about

the basic functions of the nervous system in living organisms that have it.

We’ll continue on with a discussion of the evolution of the nervous system

in organisms that have them and conclude with some remarks

on the importance of the type and number of neurons

and what those characteristics mean for the nervous system.

So with that, let us begin.

Alright. We are going to talk about this classic experiment

involving a very early robot.

It’s easily 20 years old, perhaps even a bit older than that.

And what these folks were doing, they were in the realm of artificial intelligence

and they created this little bot and given it ambulatory functions,

as well as having programmed its microchips so it could respond to various commands.

And the idea here was that the investigators took this robot

and they put it at one end of a room and told it to move across the room

and open a door on the other side.

So, it was a relatively simple task for which it had the requisite technology

at its disposal.

It had the ability to respond to programming commands

and it had the ability to move and then when it got to the other side of the room

to actually physically open the door.

So that was what they hoped to do and they wanted to monitor the robot’s progress

in understanding and responding to the commands it was given.

So it was a simple task but in the hands of… if in fact it had hands,

of the robot it was absolutely mind boggling complicated, un-daunting task.

Why is this? Well, the robot took the initial forage forward,

as it was commanded to do, but at each imperceptible advance of the robot

it had to completely restudy its orientation in the room.

It had to visually calculate and evaluate the angles.

Was it still on the floor? Was the ceiling still up there?

What about the walls of the room? Were they still there?

All of these things had to be assessed by the little robot.

Until he had done that and determined and yes, all is well,

I am still where I am, I can take the next advance forward.

Let’s say it was two millimeters, not a very big distance

but enough to then occasion the robot to have to redo all of these orientation functions

again and again and again.

So you can imagine that the graduate students involved in charge of this project

were thinking, ‘okay, let’s go get a beer because this is taking forever

and there’s nothing we can do to move this along’.

So, yeah. It was probably not the most interesting thing to watch

but it was part of the experiment and if you’re in charge of it

this is what you get to do with your very exciting life.

So the poor little robot does this again and again

and even when confronted with change that we would probably consider

to be imperceptible it wasn’t imperceptible to the robot

it was a really big change causing great consternation and reinitiation

of these functions of evaluating its orientation in space and time

so that it could make the next move forward and pursue its goal

of opening that darn door. So, it took hours, something like 12 hours

for this robot to roll across a distance of 10 or 12 feet

but it finally gets to the other side of the room

and it dutifully opens the door no big deal.

Mission accomplished.

But now because they are scientists and scientists like to do creepy things.

The scientists took our little intrepid robot and put it back at the starting line

on the other side of the room and it told the robot, ‘okay, go open that door again’.

But his time the door was emblazed with a big black X.

So, to the humans involved this is like no big deal.

Yeah, it’s a door. It’s got an X. Who cares? Whatever.

But to the robot, it caused complete confusion leading to it not being able to function because why?

Well, the robot knew nothing of X’s.

What is this thing you call X? I know not.

It could not generalize from its previous experience.

It could not evaluate and conclude that the X on the door didn’t affect its functions

it could easily still open the door. It could not learn.

As a result, the poor robot turns away from the door dejected

and absolutely unable to accomplish the task that it was given.

So, this brings us to a stark reality for that robot,

no matter how good its programming any change meant total change

because it didn’t have the information in its data banks to evaluate the X on the door

and make the decision that it didn’t fundamentally change what it was being asked to do.

His previous … I don’t know why I called it a He but I did.

Its previous experience did not provide meaningful information

against which it could judge the current task and generalize a door was a door.

It wasn’t capable of learning that idea in this experiment.

Certainly, the kinds of robots we have today are vastly better than the robots

that we’re talking about 20 or 30 years ago but the point I’m trying to make is

even if we allow for the monumentally improvement in artificial intelligence

and robotic technology that have so forth taken place in the intervening 20 or 30 years,

even if we allow for that vast change,

even the best robots that we could produce today couldn’t come close to handling

what a typical two year-old toddler child could execute

or even a comparatively lowly, simple mouse.

Its brain is eminently more capable of absorbing and processing information

than is the best robot that we have today and even an ant which we think of as

a mindless automaton, much of the time, is much better capable

of understanding information that comes in through the environment

and responding appropriately having evaluated the nature of that information.

So, we’ve got something really interesting going on.

Once we get this thing called a brain and its attended nervous system that supports it.

In contrast to the robot, which is a human construction,

a living organism has this incredibly difficult task of receiving

an endless stream of constantly changing sensory information

from the external environment. It is absolutely essential that that organism

be able to take this information in and evaluate its importance.

And then, it has to having evaluated that information, act appropriately.

One of the big things you find out when you study animals,

is that much of their day, much of their nervous system activity,

is spent deciding what information they can conveniently ignore.

And you do this all the time too.

You’re sitting at home maybe in the kitchen, there’s a whole bunch of noise,

maybe there’s a fan in the ceiling that keeping the room cool.

Maybe there’s an air conditioner, the stove might be making noise.

The refrigerator makes a humming sound.

All of these things are sensory input that your brain has to assess

and react appropriately to and you probably won’t respond to any of these things

because you’ve learned to block them out.

They’re just background noise.

We don’t pay attention, however, if the smoke alarm goes off.

BAM! You’re right on it because if the place is on fire,

you want to take appropriate action.

And in the environment, an organisms survival is absolutely dependent on

this function; evaluating what you need to know,

responding appropriately to ensure your survival that is the first job, major job,

of the nervous system.

But organisms including humans have a second major task too,

and that is to maintain the internal consistency of their inside environment.

Your body is an amazing thing.

It does all sorts of things that you don’t even think about.

And one major part of that goal is to maintain all of the functions

that are going on inside your body, inside each cell,

within certain prescribed biological limits.

We call these limits homeostasis, meaning maintenance of the same state.

And it includes all sorts of things that you basically don’t think about

much of the time. Thinks such as body temperature,

which is one of the few functions that you might think about

because your body temperature regularly fluctuates when you exercise

or when you’re out in the cold so you have to learn ways to adjust what’s going on

so that your body isn’t undone or severely impacted in a negative way

by changing temperature.

So that’s one you might think about but you probably don’t think about the water level

in your cells much, you don’t think about the pH in your stomach.

There are all sorts of things going on all of the time.

All these body regulatory functions,

all of them have limits within which these functions need to take place,

otherwise, you get into trouble.

And I think it goes without saying, but I’ll say it anyway,

a lot of these functions are set up particularly in advance vertebrates, like humans,

in such a way that we don’t have to think about them and that’s a really good thing.

You have an automatic nervous system that takes care of all of this stuff

so that you don’t have to give it a thought and that’s good because for instance,

if you had to remember to breathe at some point you would have forgotten and

therefore would not be listening to this module today.

So, the nervous system does all of these boring, think-less things

that we never have to think about and it’s a really good thing that it does.

So, if we compare, let’s say, vertebrates, things that have a vertebral column,

with other less developed organisms

(they might have a nervous system but not one like a vertebrate does)

we can start to look at some stark differences in those different kinds of organisms.

All organisms have the same very basic needs

and first among them is to avoid being eaten by some other organism

because that pretty much ruins your day and means you will not be going on

to the next part of our game here.

But in addition to avoiding predation,

organisms have to find, eat and then process food

from which you drive energy to run your cells. A good thing.

If you’re successful in avoiding predation and getting the necessary resources for life

(including not only food but water) then you would have to find a mate

so that you can reproduce yourself and send your genes into the next generation.

Of course you need some sort of shelter

in which you can shelter your body in inclement weather and so forth.

So, basically, all of organisms that we’ve going to be interested in

have those four basic survival functions,

plus some others that we’re not going to talk about because you know, life is short.

But if we look at higher level vertebrates in here we include humans,

of course, but some other vertebrates as well.

We might include dogs, we might include cats, we might include whales,

or chimpanzees, or porpoises.

In addition to the survival functions,

they have some other really interesting things at their disposal.

Many of them can perform music of various sorts.

Humans are not the only animals that can do this, others can as well.

And if we compare the possibilities for vertebrates against our intrepid little robot,

we find that virtually all of the activities that these higher level of vertebrates can do are monstrously difficult.

If you had to write a computer program to process the kinds of things

that advance vertebrates could do, you’d be at it for quite a long time

and you’d be a genius and you’d make a lot of money

because nobody’s figured out how to do that yet.

If we make a distinction between simple organisms

as capable of doing the first four things we talked about on this list,

we can distinguish them from the more complicated creatures

because we and other species that I just mentioned,

can do some really complicated, arcane, not necessary for survival

kinds of things that include artistic kinds of things.

Okay. So, what are those things that organisms can do that

robots or a lower level animal cannot do and how is that possible?

What is the explanation that provides the distinction between low level processing

or survival based functions and the higher, or cognitive, or executive kinds of functions

that advanced vertebrates, like us, are capable of.

Well basically, the difference is we have these networks of neurons that form

the nervous system that have the very important function of signal transduction

of sensory input and other kinds of input and once the signal is received,

the organisms can process that signal

and do a whole variety of different things in response.

One thing they might do is compare it to previous experience.

In advanced vertebrates, such as ourselves, and the other things I mentioned previously,

those organisms can formulate a strategic response

so that whatever the problem that arises can be taken care of.

We’ll give some more examples in greater detail in a few minutes

but the point is, that you have this incredible thing called the nervous system

that consists of neurons that allows you to execute all of these very sophisticated,

not easy to replicate, kinds of functions within the vertebrate body.

And this has been shaped by millennia, through the force of natural selection.

It has really come to fruition in terms of cognitive abilities

and perhaps some extra cognitive abilities,

thought processes that are really important to the way the vertebrate mind works.

So, if we look at sort of a spectrum of different possibilities for the nervous system,

the nervous system as we understand it basically begins in the lowly worms

and other organisms like starfish.

We have a very, very basic level of nervous system

that I’ll go over in more detail in a minute.

Now, as an aside, there are entire classes of really sophisticated organisms

that lack a nervous system completely and these are by large the more advanced plants,

the angiosperm or flowering plants are a great example.

They have no nervous system but they can do all of the homeostatic functions

and survival functions even without it.

So why have a nervous system if you can have a beautiful, lilac tree, or daisy flower,

or rosebush, if you can have those organisms without a nervous system?

Why did we bother to invest in a nervous system?

And we are going to be taking that up in a few minutes

because it’s a thoroughly important question:

why is the nervous system so valuable to us that we would not want to forego it entirely

like even advanced plants has?

Why do we have this nervous system?

Well, the basic answer is this:

once the organisms on earth stopped being just unicellular organisms,

in other words, very early life on earth in fact,

for the first three billion years of existence of life on earth

all of the organisms present had a single cell.

Eventually, after three billion years after trying and retrying,

the single cell approach to life,

cells began to grip together and form multicellular forms.

And even small multicellular forms could exist pretty much as multicellular animals,

a group of loosely joined cells that shared some of the functions between cells.

But by the time we get to the really complicated organisms

that have hundreds of millions of cells in their composition,

all of a sudden getting important information from one end of the organism,

like the head to the big toe,

was really complicated and couldn’t be done efficiently

using the kind of processes that were available to single celled organisms

or even advanced plants like the angiosperms.

So, once organisms, particularly animal organisms became multicellular

the processes by which a message could be communicated

from one part of an organism to another was simply too slow for the large organisms

to respond quickly to changes in internal or external environments

and this problem was solved by developing a nervous system

which allows for at least in our time scale,

the nearly instantaneous transmission of a message from the head to the toe.

It’s like when you walk into a room and flip on a light switch

it’s nearly instantaneous that the light goes on.

And yes, I know that there is finite teeny-tiny period amount of time

which there’s no light after you flip the switch

but it’s so fast that it might as well be instantaneous

and that’s the way the nervous system behaves in a vertebrate body.

So let’s talk a little bit about the evolution of that nervous system

from the relatively simple forms with which it started

to the very advanced forms like that which humans have.

All told there are two basic types of nervous systems.

We call these diffuse on the one hand this if the primitive form,

and the other alternative modality is to have a centralized nervous system.

So in the case of a diffuse nervous system…

I wonder if I can get my little yeah there we go pen go in here.

Okay so an organism with a diffuse nervous system

is something like the sea anemone that you see here.

It’s just this bundle of little spaghetti like lines.

Those are the neurons, the nerve cells,

and they’re not highly organized they’re just kind of there like a net

like a hair net…something like that.

Another example of a diffuse nervous system is the starfish you see here,

and it looks a little bit more organized than this sea anemone.

And it probably is.

It’s a little more advanced,

but both of these animals of the sea anemone and the sea star are radially symmetric.

They’re not, you can’t draw a singular line down the body of these animals

and get two equal halves because they have many planes of symmetry

by which they can be divided in half.

So they’re fundamentally different from other kinds of animals.

The other kind of nervous system,

the centralized nervous system, is more common.

It’s the more advanced, and here are some animals.

Hey, look at all these red lines!

I could really get carried away here.

Okay so these are all animals that have a centralized nervous system,

but even if were talking about a centralized nervous system

where large numbers of neurons are gathered together into functional units

there are still some fairly cosmic differences

between primitive and advanced centralized nervous systems.

So we’ll talk about those right now!

In terms of the evolution of the nervous systems,

even those which are centralized,

we would begin with the flatworms.

They are the least developed organisms with a centralized nervous system.

And what makes this a centralized nervous system

is that we have a brain which is an amalgamation of a whole bunch of neurons

into a single unit that has a specific functions associated with it.

This is a primitive organism because we have two nerve cords extending from the brain.

So, this is the inaugural step in the formation of an advanced nervous system

but it is not full advanced because of the characteristics I mentioned

we then move into the annelids or the earthworms which you see down here.

And now, we have a completely centralized brain.

It’s this one in the flatworms consists basically of two halves

well in the earthworm the two halves get fused together

so it’s more highly centralized.

We also have only one nerve cord coming out of the brain instead of two.

Although, we have highly segmented helper brains

or ganglia that run along the length of this single nerve cord.

So it’s more advanced than the flatworms’

but less advanced compared to what comes after it.

What does come after it?

Well, the next step in this evolutionary trajectory would be the giant squid that you see here.

Where is my line? There it is.

Here is our squid, and you can see that this is really nicely centralized.

We have a nice big brain. We also have eyes in the squid.

Who knew?

We have some ganglia left along the central nerve cord,

but more importantly what we now have is a whole bunch of peripheral nerves

that come off the central nerve cord and innervate other parts of the body.

So, those are some of the developments that make this a higher organism

that is to say the squid than that which came before it.

And lastly, we get to the pinnacle of vertebrate evolution

we have the human being.

And we now see a very important thing happening up here in the brain.

This is our major advance we call this a cephalized nervous system

because all of the executive functions are gathered

and put into the brain and because the word in Latin for brain is cephalous.

If we say a nervous system is cephalized it means all of the important stuff well,

that’s not entirely true,

all of the executive functions and regulatory functions are given to the brain.

Which is in the head and therefore is called cephalic.

So, the human nervous system, the vertebrate nervous system,

is not only centralized its cephalized.

So, as I mentioned, to recapitulate the evolution

of simple nervous systems started with the flatworms,

which were the first bilaterally symmetrical systems.

Although we still had two longitudinal nerve cords.

Boy! Can I speak in English? Help me.

Then we moved onto the… from the flat worms to the annelid worms,

the earth worms that are moderately centralized.

They had a very distinct brain with some ganglia coming off the brain.

And then we moved on to the more advance stuff of which we're the pentacle.

So prior getting into humans we had further cephalization concentration

of executive functions in the brain.

We had some other things to show up like eyes, certainly important.

And control of specific functions, things like locomotion or motion and feeding

get compartmentalized and concentrated

in the highly centralized nervous system in the brain.

So additional examples in addition to the squid

are octopuses have a highly centralized nervous system as do insects.

Yes, insects do have a nervous system.

Who knew? And lastly, we get to us.

Where we have lots more neurons present,

a very high degree of centralization as you would expect

but also this thing called cephalization

which is the concentration of all of these important functions in the brain itself.

We also have the division of our highly cephalized brain into distinct units.

We have lobes that are associated with particular functions like olfaction.

Or executive function in the forebrain, the conscious thought,

ability to reason, that sort of thing, in the forebrain.

I mentioned the five regions of the brain which we’ll go over again in another lecture.

And of course, because we have all of these amazingly important functions

now residing in a single location in the vertebral brain

we’ve gone through an awful lot of trouble to protect the brain

by the use of a skull and several other adaptations

whose function is to preserve the integrity of the brain against assault.

So, in terms of vertebrate nervous systems and the characteristic I just mentioned.

We’re talking about all of the things from fish

which are vertebrates to us which are vertebrates.

Now, at this point it’s a good time to mention that there are three kinds of neurons.

The nervous system, as you might expect, is composed of these cells called neurons.

And despite the multitude of functions that these neurons have to carry out,

there are only three types of neurons

irrespective of which kind of organism we’re talking about.

So, what are they?

Well they are first of all the sensory neurons.

Which have the job of carrying information, not surprisingly,

from the sense organs to the brain and the spinal cord,

and these are the things that help us perceive things

that are going on in the external environment

and by taking the information up the spinal cord

and then to the brain where the information gets analyzed and the response is formulated.

We have the ability to take whatever response is appropriate

given the information at hand.

So these are very important neurons in helping us respond to

and perceiving the environment.

Secondly, we have motor neurons, which carry messages from the brain and the spinal cord

back to muscles and glands which are in the periphery.

This is important because as I mentioned

you perceive information from the environment

through your sense organs feed that information to the brain.

The brain analyzes it and figures out what response you should take,

and one response you might take is to decide

you know what Danger! Danger! Let’s get out of here!

And then the brain would send a message

using your motor neurons to your muscles

saying “get the heck out of dodge. There is danger.”

and that’s kind of how it works.

Finally, we have these things called inter neurons

because you know if you’re sending a message from your brain to your big toe,

you know, that’s a lot of ground to cover.

And so, your response might start up in the brain,

feed information to the spinal cord,

and then to a motor neuron.

But probably if you’re sending the message a long way

then the motor neuron would be given the information by an inter neuron

that would serve as an intermediary messenger

between the spinal cord and the motor neuron that generates response.

So even though the stuff we’re going to be talking about is incredibly complicated,

the basic machinery used to perform those functions is pretty simple.

We’re always talking about neurons of one form of another.

And there’s only three. How hard can this be, I ask you.

So here’s an individual neuron,

and it very nicely shows the important structure of the neuron

that I’m going to want you to be familiar with.

First of all, we have what we would call a cell body,

and this is the part of the cell that contains

all of those organelles that you learned about in basic biology class

that carry out the important functions of running the cell.

Things like the nucleus, the mitochondria, the Golgi bodies, the ER

all of that stuff is contained here in the cell body

which is also known as a Selma in the case of a neuron.

So that’s the first important part of the cell I want you to know about.

The second part of the cell which is distinct, two cells that are neurons

are these highly branched functions that branch off or come off of the cell body.

And these are given the name dendrites.

They’re very important because they serve as part of the mechanism

that helps this neuron communicate with other neurons.

So that’s the second important part the dendrites.

They’re distinguished by the fact that they have

all these little branches on them,

and incidentally the word dendrite comes from the route dendrology.

Dendrology is the study of trees.

Trees have branches, and that’s why these highly branched processes were named dendrites.

Because biologists are very clever.

I’m sure you will agree.

Okay! The third important part of the neuron

is this long unbranched process, which we call an axon.

A.X.O.N.

At the end of the axon we see some branches,

but it’s not the same as the dendrite which is branched throughout its length.

So this third important art is called the axon.

Now over here you see a whole bunch of neurons together.

So these things, these big yellow globs, are the cell bodies,

and all the rest of these spaghetti like hairy processes things

are the collection of axons and dendrites that join these neurons together.

And don’t worry well talk about this again.

“Oh joy”, I hear you cry.

So if we add it all up

and try to account for the difference between, let’s say, a nematode and a man

it’s actually pretty easy.

It’s simply the number of neurons and the structural arrangement in the nervous system.

So basically the grater the number of neurons an organism has

the greater the complexity of that organism’s thought processes

and the greater the potential range of adaptive responses

to any particular stimulus will be.

So if we take for instance a flatworm that faces mortal danger,

its primary mode of dealing with that problem is simply to leave the area,

to get away, to flee if it can do so.

However, if were talking about a human facing mortal danger,

that human responses are much more nuanced

and may include things like prevention…

don’t go into an area where danger lurks for instance.

But, having been presented with danger

you can then form a plot to escape

or maybe you had the foresight to bring a weapon with you

so those would be additional avenues by which you could avoid the danger that is present.

Or maybe you got your cell phone on you

because God knows all youth have a cell phone.

I don’t understand this.

My children feel naked without their phones.

I’m, you know, I’m perfectly happy with a rotary phone that hangs on the wall,

but you know I’m old. Okay.

So if you’ve got your phone on you,

you can you know do a quick dial to a friend and say

“Help me! Help me! Send to cops.”

Or whatever, and so you have this other modality by which you can respond.

Because you’ve got these extra neurons and a highly centralized and cephalized brain.

Good job!

So as the complexity of a species brain increases in the vertebrate lineage

the number of neurons also increases

and that is the one major characteristic of

increased executive function with higher numbers of neurons.

In addition, the existing neurons,

because even more intimately entangled through

the elaboration of dendrites in other words,

the number of connections between the neurons that exist in highly complicated species also increases.

In addition, as the number of in neurons increase.

They also begin to cluster in these specialized units

that we were talking about

and that increases again the sophistication of processing that is possible in that brain.

So circuits develop among various structures within a highly sophisticated vertebrae,

vertebrate brain,

and the idea behind the circuits is to be able to rapidly share and trade information

in a rich multi-layered perception and potential response to the world.

And really advanced vertebrates,

have an existing, excuse me,

additional thing which we call memory

that can be used to make future decisions

based on things that have been happening in the past

and were stored in the brain.

So you can see that as the number of neurons increases.

We have no idea what kind of memory a flatworm has, probably not much.

Probably most of its functions are instinctual in nature,

but by the time we get to humans,

we can log all this information into our data banks.

We can store it, we might modify it if there’s an emotional attachment to it

or if there’s a learning function that goes with it.

We’ve got all of this function that we can use

to give ourselves multiple options for any situation that arises.

In fact, the human brain is so darn complex

that we can just we can do amazing amazing

I mean I cannot emphasize how incredibly amzing

all of these things are.

Not just survival that we’re looking at,

humans want to do all sorts of other things.

Like anticipate the future.

Think about how amazing that is.

We not only know that a future exists.

We can imagine different outcomes for that future.

We can play different scenarios in our mind,

and once we’ve done that we might take actions born of our internal desires

and our memories and our life history

to secure a particular outcome in that future.

It’s an amazing thing because it requires the integration of all things,

like memories of our experiences.

We might not even have our own memories.

We might have memories that are given to us by stories,

by the sharing of other people’s experiences and desires and attitude

through language, through books, or through sitting at the dinner table

listening to stories from our collective pasts.

It’s amazing!

So we get these ideas that don’t even come from our own experience

but from other people’s,

and we integrate them into our data banks.

Humans also have,

perhaps a unique ability, we're not really sure about this,

to conceive a really things that you can’t really see necessarily

but you know it when you see it

to paraphrase a supreme court justice.

So we can conceive things like beauty.

So this beauty, does a flat worm think of beauty does a sheep?

I don’t know. Certainly humans do.

I think there’s some birds that do

because they certainly invest a lot of energy into making beautiful males

to be attractive to females who choose normally these sexually departments.

So, you know we’ve got some other organisms that then might have a sense of beauty

but humans at least have the ability to not only see it

but write about it or make representations of it.

It’s kind of amazing.

We’ve also cultivated a moral sense,

an idea that some things are right and some things are wrong.

Now here we do not stand alone.

There are other organisms among the vertebrates who also have a moral sense,

but in humans it also becomes a full flower or methyl flower.

We at least know what’s morally correct.

We doesn’t always do it, I know, but there’s that.

We understand virtue. We understand good and evil.

We are at east hopeful that we will choose the good and not the evil,

but as you know that doesn’t always happen either.

Even more importantly and more interestingly,

we have this massive creative sense.

Humans are by their very nature artists

and this comes into play very early on in the human lineage

where people were drawing pictures on cave walls

and making pots and even when they were doing something fairly proletarian,

like making a weapon,

often they decorated it just to make it pretty,

obviously it didn’t improve its function,

but it made it look pretty.

That’s what humans are.

We have this genius and this inspirational sense

that motivates us to do these really really interesting things

and then beyond that we’ve got this organization of society

that is not the product of biological entities.

We’ve created a culture.

We have a complicated economic system.

We have different economic systems.

Some countries like it one way, some another.

We have technology. We have science.

We have humans who have, in their free time, just you know one day created calculus.

You know? You just...

Isaac Newton invented calculus one day doing nothing else.

After he was done inventing gravity,

well he didn’t invent it, but he figure it out.

How it worked.

And then you’ve got Einstein and MC squared and Mozart.

How do you account for Mozart?

You know it just boggles the mind,

but that is the kind and the level of thing of which humans are capable

because we have this thing called a nervous system

that operates at an excessively high level.

So there’s your study guide for the science of perception

and we’ll take it up

we’ll take the nervous system up again in the next two presentations.

I know, no need to thank me.