Hey, welcome to Week Four. You know what they say, you make it to

week four you might as well go to the end of the course.

Glad you're with me. this is going to be a fun week.

it's going to Highlight an approach to Psychology that we're calling

behaviorism. But I want to do really in this very

first lecture of the week is set the stage.

And give you a sense of why, why and how behaviorism was a very strong reaction to

a couple of things going on at the time. The time being early to mid 1900's.

Alright? So.

let's get at/g. Right week 4, lecture 1, Forces of

Nature. I, I decided I would inhabit the other

corner of the screen for a while. You know, I was getting kind of bored

over in that corner, so I snuck over I hope that's okay with you.

all right, here's what I want to do, here's the story I want to tell today.

I want to start a little sort of, pre-Darwin, but kind of talking about

some of the strong influences of Darwin. And specifically this notion of

artificial versus natural selection. You've, you've seen that I've titled this

lecture Nature because this was a time when genetics really started to be known,

understood. And the full influence was.

embraced maybe even over embraced a little bit.

So, let's start here. When Darwin was postulating this notion

of selection and specifically that the characteristics of an organism evolved to

fit the habitat. One question at the time was, well, how

does that happen? You know, how can an organism evolve its

characteristics? And of course, Darwin suggested that,

well, whichever one has characteristics that fit the environment best are more

likely to survive. More likely to reproduce.

But there was still that question like okay let's say I have a big beak and that

helps me survive and that helps me reproduce.

But how does that get translated to future generations?

Now Darwin knew that it did. He didn't know how.

But he had seen things like, race horses. So, this is this is an image that meant

document 1800s. And clearly, there was racing going on

there and there was racing going on well before.

And there was breeding, critically, going on.

Now, breeding is what some people call artificial selection.

And of course in the horse racing world the idea is just this.

You take a really fast horse and if you breed it with another really fast horse,

then the offspring are more likely than average to be fast horses.

So, and you know, assumable that reflects some physical characteristics.

The build of the body, the musculature, something like that seems to be handed

down. Seems to somehow go from parent to child.

and, you know, carry on in that way. what we all think now of genetics, but

they didn't really understand what it was.

Now, that's all fine and good perhaps for physical characteristics.

But it also, critically for this course, seems to be true for psychological

characteristics. Now this is maybe a little bit of a

stretch, but dogs obviously also have been bred to an extreme degree.

If we take a black Lab like this, look how beautiful and black.

I used to have a black Lab. Kaley, I think of Kaley when I see this

picture. not the duck part.

But anyway dogs came from wolves initially.

And people started breeding the most gentle, tame wolves with each other,

ultimately leading to a much tamer dog than a wild wolf.

and then they started getting even more specific.

So, they would breed the darkest pups with the darkest pups and do that

generation after generation. And eventually by doing that were able to

create dogs like these black labs that are pure black.

this is not natural you know. But again that's a physical

characteristic. But the reason I chose the duck picture

is the other thing that was bred into labs, was for them to have a gentle

mouth. What they call a gentle mouth.

So, if you're a duck hunter, boo on you, but okay.

If you're a duck hunter, and you shoot a duck.

Often you shoot them over water or you shoot them, you know, for relatively far

away and you don't necessarily want to go find them.

You wouldn't necessarily be very good at finding them.

So, the ultimate dog companion for a hunter, especially a duck hunter, was one

that loved to swim. I mean, I like that, love to swim.

Isn't that a psychological thing, what your tastes are?

One that had a gentle mouth so if a duck was in the water it would go and get the

duck. And it would bring it back to you but it

wouldn't bite it, it wouldn't tear it, it wouldn't shred it apart.

In fact Labs are generally known as being gentle disposition dogs and they were

bred that way. The gentlest dog the one that did not eat

the ducks, the one that did not scar ducks there.

The ones that were bred to produce this dog and of course you'd like one with a

decent nose. Because if the duck is somewhere in the

field way over here you want the dog to be able to find it.

So, a dog that loved to swim, that had a good nose and that was able to bring,

retrieve a duck without mutilating it or harming it.

Those, you know? That's a fine blend of physical and

psychological characteristics that, that you want in a dog.

And they were able to breed it. So, this is what really gave Darwin the

original idea that, okay, well in order for my notion to work.

It's just instead of this artificial selection, that we do when we breed.

There has to be some natural version of that.

So, there has to be some, if having certain traits is desirable to members of

the opposite sex, then that will function like artificial selection.

That the couples will select. Based on who they're going to pair with,

based on certain characteristics. and that will function the same way.

Those characteristics will carry on. so that was Darwin's idea.

But, here's the kicker. Now that became, really kind of,

exciting. A lot of people were interested in this.

A lot of people were thinking about the implications.

And then, some people started thinking, well maybe we should be artificially

breeding humans, to an extent. So, the scientific field call eugenics

emerged. that really emphasized genes and

suggested that, you know, if we want to advance as a species.

If we want the human race to somehow become "better," whatever that means.

That's part of the problem with eugenics. Maybe we should look at how humans

reproduce. Maybe we should not allow anybody who

wants to reproduce with anybody who's willing.

Maybe we society should put breeding restrictions on our citizens.

So, this opened this huge, you know, you see, eugenics is the self-direction of

human evolution. and so you see things in their roots

here, you know, mental testing. The idea was, "well, wouldn't we rather

have the intelligent people breeding instead of the not-so-intelligent people?

So, if we could test and find intelligent people.

wouldn't, wouldn't we rather have those people as the ones that breed and, and

produce the future of humanity. you know, that, that's a critical thing.

And it really, of course obviously, branched out.

branched out, sorry for the pun. But it got pretty extreme, so at some

points people would say things like, well mixed race couples cannot have children

or should not have children. mentally retarded children should not

have children. Homosexuals perhaps should be prevented

from having children because at that point in time homosexuality by, by many

was seen as a problem. Of course certain you know like well I

mean it reached its peak in Nazi times, in the 1940s.

When Hitler went beyond saying we should prevent certain groups from breeding and

started literally exterminating certain groups.

You know the Jews being especially high on his list.

That was the extreme of eugenics, and it's a really kind of crazy time in a

way. It's a hard time to think about because

you have people like Hitler doing horrific things based on scientific

principles. It's the kind of thing that scientists

don't ever imagine happening with scientific ideas.

But it sure as heck happened, and it happened in a very extreme way.

Okay, so this is the context that really, sorry let me step back.

This is the context that really was setting the stage for a push towards

genetics, and the role of genetics. The role that genetics plays, so that's

the role of what we're going to call nature in this course.

How do we study nature in psychology? How do we study the influence in nature?

I'm going to put eugenics to the side for a second, but just if we're interested in

the extent to which something is genetically determined, how can you know?

Well one way, and something you're going to hear of in this course quite a bit, is

evidence from so-called twin studies. Twin studies often compare identical

twins with fraternal twins. Or sometimes called mono zygotic verses

di zygotic. What that means is the zygote is the

actual fertilized egg. And you see with a mono zygotic there's

really just one, with a di zygotic there's two.

that's the mono verses di. So in the case of a mono zygotic twin

pair, originally it's one egg fertilized by one sperm.

but then that egg inside the placenta splits into two individuals.

sorry, that egg splits into two individuals, but then they each go off

and become two babies. But they have an identical genetic

structure because they started out as the same sperm matching with the, same egg.

Whereas with the dizygotic case we have two separate eggs fertilized by two

separate sperm cells. So, really in the dizygotic or fraternal

twins, those two children are no more alike genetically than any brother and

sister would be. any brother and sister by the same

parents would be. so we get this difference.

Here we have two children that will grow up together.

And so they'll share the same environment but they don't really share that strong

of a genetic connection. They do, as family members, but not

nearly as strong as the monozygotic twins, the identical twins.

These twins will grow up together, so they'll have a very similar environment.

But they also have essentially identical genetics.

And so we can compare things like the following.

We can compare concordance rate. So what's a concordance rate?

Well let's take alcoholism, a concordance rate says that if one of the twins is an

alcoholic let's say. What is the likelihood that the other

twin will also be an alcoholic? Okay, that they're in concordance, that

they agree. And you see, for example, with females

and alcoholics from monozygotic twin, that's about 0.3.

for dizygotic it's lower, maybe about 0.25.

That's for females. For males, it's higher generally, males

have a higher chance of being alcoholic in general, but especially for these

monozygotic. So if you're an identical twin, and your

twin is now alcoholic, there's nearly a 40% chance that you as well will become

an alcoholic. More importantly, this difference that

you see across monozygotic versus a dizygotic.

is seen as evidence for the contribution of, of genes, of genetic factors.

So, by looking at those differences, if you assume that the environment of these

kinds of twins are roughly equated. Then the difference you see should be due

to this fact that these monozygotic twins share a lot more genes.

That's why the concordance rates are higher, that's why there is a greater

likelihood of you being an alcoholic if your twin is.

You see this pattern across many things, so for example, schizophrenia Alzheimer's

disease, autism. You know, it looks huge with autism here

major effective disorder, that, that means emotional disorders that's like

depression, for example. and even reading disabilities.

And every time you kind of, see this pattern, it is taken as suggesting that

there is a genetic influence. So, all of this to say that there is

noted that in a lot of the issues we'll talk about in this course.

A lot of issues that have psychological evidence.

Genes are playing a role, nature matters. Now the real question though, of course,

will be how much does it matter? How big of a role is it playing?

and in the eugenics kind of view, the idea was oh, well it's playing a huge

role. Let's actually, you know, tailor our

species via genetics. Again, a little creepy.

We'll come back to that. but that was really kind of big and all

of this was kind of big in the early 1900s.

People were very interested in genetic influences.

Okay, so I'm going to leave it there for now.

I've got some videos here, one comparing artificial versus natural selection.

A couple, these are longer ones, and these are more related to that Eugenics

issue, the creeping. So for example, from Darwin to Hitler,

that's a lecture that somebody gave being pretty provocative in some of these

things. But if you find that fascinating, I

certainly was amazed when I first learned about Eugenics and the role it played in

early 1900's. So,you can check that out here's some

information about twin studies. And then in readings again, some more

information about twin research. This is actually a journal about twin

research and human genetics just to show you that it's still, you know, a very,

ongoing area of research. There's a couple of free papers, if

you're interested, that you can take a look at again if you want to really see

the raw science that's being done on this.

And then there's a general discussion of the nature versus nurture debate.

So, I've highlighted nature in this talk, and in the next lecture I'm going to

highlight nurture. And I will highlight the fact that this

really has become a bit of a battle for psychology.

Of trying to understand how much of us is determined by our genetic heritage.

And how much is determined by the environment around us.

So to hear more about the environment, tune in to the next lecture.

See you later, have a great day as always.

Bye, bye.

Lecture 1 - Forces of Nature (15:18 min)

Introduction to Psychology

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