Intro to psych - PowerPoint Presentation

Slide1

Intro to psych4/10/14

What Motivates Us: SexSlide2

Sex

People say sex is their favorite activity

They rate it higher than sports, hugging and kissing, eating, going on trips, shopping,

etc

The average American devotes 4 minutes and 3 seconds to sex (per day)

What does this tell us?

1) People don’t actually spend that much time on sex

2) Regardless of how much time we spend on sex, it’s hugely important in our lives

Everything

follows

from it: marriage, family, children, some aggression, competition, art & music

If we were a creature without sex, everything would be differentSlide3

Sex

The very existence of sex is a mystery

Many animals have just one sex, and reproduce by

cloning

But complex animals (like humans) have two

sexes

To reproduce, each animal gives half its genes to its

offspring

It’s a puzzle how multiple sexes ever evolvedSlide4

What are we going to talk about

?

How and why males and females are different

What people find sexually attractive

What are the origins of sexual preference?

Sex is difficult to talk about

Very emotional and intimate part of life

Lots of moral implications & consequencesSlide5

Morality & Inevitability on Evolution, Sex & Gender

Biologists argue that sexual behavior, action, & desire are a biological adaptation that exists for us to be able to spread our

genes

By this definition, non-procreative sex does not serve the reproductive goal and may be considered unnatural – Does this mean it’s wrong

??

If sex for reproduction has evolved out of natural selection, does this make it good/moral/inevitable?Slide6

Morality & Inevitability on Evolution, Sex & Gender

“

Nature does not dictate what we should accept or how we should live our lives. Well into my procreating years, I am so far voluntarily childless, having squandered my biological resources reading and writing, doing research, helping friends and students, and jogging in circles — ignoring the solemn imperative to spread my genes. By Darwinian standards, I am a horrible mistake, a pathetic loser, but I am happy to be that way, and if my genes don't like it they can go jump in the lake

.” – Steve PinkerSlide7

Morality & Inevitability on Evolution, Sex & Gender

What is the point of this quote?

Certain things we do exist to serve natural selection

But that doesn’t make them right

If you think that something is only right if it leads to reproduction, then you’re probably not going to think very much about birth control

If you think something is wrong if it’s unnatural, then you’ve got some strong beliefs on flying in a plane, or refrigerating your food, or surviving a severe infectionSlide8

Morality & Inevitability on Evolution, Sex & Gender

Our bodies & brains have

evolved

for reproductive success

But we also use our brains to choose our own destinies

Keep morality in mind as we discuss different claims about what has evolved & what hasn’t

But what about inevitability?Slide9

Morality & Inevitability on Evolution, Sex & Gender

“If

a child has had bad teaching in mathematics, it is accepted that a resulting deficiency can be remedied by extra-good teaching in the following year. But any suggestion that the child's deficiency might have a genetic origin is likely to be greeted with something approaching despair. If it's in the genes, it is determined and nothing can be done about it. This is pernicious nonsense on an almost astrological scale. Genetic causes and environmental causes are in principle no different from each other. Some may be harder to reverse, others may be easy. What did genes do to deserve their sinister, juggernaut-like reputation? Why are genes thought to be so much more fixed and inescapable in their effects than

television

or

books?” – Richard DawkinsSlide10

Morality & Inevitability on Evolution, Sex & Gender

The point: What causes something to be is logically separate from what can reverse it

Genetics that can be reversed

Example: My bad eyesight

It’s bad because of my genes; my mom’s side has terrible eyesight

But it’s easy to fix – glasses and contact lenses

Biologically caused but easy to fix

Cultural and hard to reverse

Example: the way society treats obese people

How thin or how fat you think someone is

is

not genetic

It varies a lot from culture to culture

But once it is part of the culture, it’s very hard to get rid ofSlide11

Basic Sex Ed

What’s the difference between male & female?

Penis & vagina?

Nope – there are some animals that have neither one

Definitions:

Male: possess a small sex cell that carries genes and nothing else (sperm cells)

Female: possess a big sex cell that carries genes and food and has a protective covering (egg)Slide12

Basic Sex Ed

Why is it that the animal with the tiny sex cell is typically larger and more aggressive than the animal with the larger sex cell? Slide13

Basic Sex Ed

“Parental Investment”: Any investment that will increase an offspring’s chance of survival at the cost of the parent’s ability to invest in other offspring

Typically with mammals, females have a much higher parental investment

Female Parental Investment: carries a fetus inside her, nourishes it with her blood (for many months), nurses and protects it until it has grown big enough to fend for itself (for years)

Male Parental Investment: a few minutes of copulation and a tiny sperm cellSlide14

Basic Sex Ed

This leads to the evolution of different psychologies in males and females

Males:

A single male can fertilize several females, which forces some males to go

mateless

Those who mate with as many females as possible will have the most reproductive success, and the genes that allow them to do so will be passed on to future generations

Females:

Females can always find mates, so numbers don’t matter

Those who mate with the

right

males, those whose offspring have the best chance of surviving, will have the most reproductive successSlide15

Basic Sex Ed

The competition to find the

RIGHT

mate explains the size puzzle

Males are typically larger because they have to compete with other males to mate with a certain female

Females are choosy! Only the best mate for me!

Males have to compete to woo the female so, often, males evolve special displays which exist only to be beautiful and to be attractive to and attract matesSlide16

Basic Sex Ed

http://www.arkive.org/superb-bird-of-paradise/lophorina-superba/video-99a.htmlSlide17

Basic Sex Ed

Summary of the evolution of sex differences

Differences in Sex Cells

Differences in Parental Investment

Differences in the sorts of physiological & psychological mechanisms that evolveSlide18

Basic Sex Ed

Sometimes, parental involvement is reversed

Males are heavily invested, females not so much

Example: Pipefish

The male takes the eggs from the female and puts them in a pouch that plugs in to his

bloodstram

Then the female takes off

In cases like this, the females are often bigger and more aggressive than the males and they compete for the attention of the males

Penguins!

Both male and female have equal parental involvement

Both have to take care of the egg

Because they’re equally involved, penguins are usually the same sizeSlide19

Sex Differences Among Humans

How we mate

Polygamous as a species

“Serial monogamy” as a

culture

The average human male is 15% bigger than the average human female

This suggest there has been male to male competition in our evolutionary history

Which suggests there is unequal parental investment

Males are generally meaner (physically violent)

In utero, as children, as adultsSlide20

Sex Differences Among Humans

Sexual Choosiness

Do males and females differ in the extent to which they will favor anonymous sex?

Parental Investment tells us that males should be

It might result in impregnation and the spreading of genes

Doesn’t carry the same level of investment required for a female

Females have to be picky about who they mate with

Important to remember these systems evolved before birth control & vasectomies existedSlide21

Sex Differences Among Humans

Sexual Choosiness

Prostitution – almost universally a male interest

Porn – human universal

Preference for sexual variety

The Coolidge Effect

President & Mrs. Coolidge are being shown around a farm

The farm guy points out all of the hens to Mrs. Coolidge

She wonders why only one rooster? Is that enough?

The farm guy says the rooster has sex “dozens of times each day”

She says “Tell that to the President”

So he does. The President asks if the rooster has sex with the same hen every time

He doesn’t. It’s a different hen each time.

“Tell that to Mrs. Coolidge”Slide22

Sex Differences Among Humans

What does The Coolidge Effect tell us?

Males mated with a female become uninterested in further copulation

But if a new female is available the male becomes interested in copulation againSlide23

Sex Differences Among Humans

How do we find out which males are likely to fall under The Coolidge Effect?

Direct Measures

Surveys

Ask questions like “How many sexual partners would you like to have in …the next month/the next 2 years/your lifetime?”

Men answer 2/8/18

Women answer <1/1/4-5

Experiments

A very attractive man & very attractive woman approach people on a college campus (they’re actors, not people from campus, so no one knows them)Slide24

Sex Differences Among Humans

These attractive actors say “I’ve been noticing you around campus. I find you very attractive. Would you

Go out with me tonight?

Come over to my apartment tonight?

Go to bed with me tonight

?

Over ½ the women approached say Yes I’ll go out with you tonight

Very few women agree to coming over

No women agree to going to bed togetherSlide25

Sex Differences Among HumansSlide26

Sex Differences Among Humans

Men:

50% say yes to going out tonight

69% agree to coming over

75% agree to go to bed together

Of those men who say

“no”

to going to bed, 25% apologize profusely and give an excuse as to why

“My fiancé is in town

somethingsomethingsomething

”Slide27

Sex Differences Among Humans

What about sexual behavior?

Difficult to figure out by studying heterosexual sex

Men & women have different priorities for sex, which dictate their behavior

Homosexual sex happens purely out of sexual desire and is better to study to determine sexual behavior

Lesbians tend to be much more monogamous than gay men

Before AIDS, studies found gay men to be very promiscuous (often hundreds or thousands of partners)

Women don’t have this level of promiscuitySlide28

Sex Differences Among Humans

Gay men are doing exactly what the average heterosexual man would do if he had that many willing females to choose fromSlide29

Sex Differences Among Humans

What about sexual attractiveness?

P

eople

are asked “Who do you want to be with/marry/have as a partner?”

Females & Males:

kindness

and

intelligence

Females

More focus on power and status

High interest in investing in children

Males

More focus on the ability to

have

childrenSlide30

Beauty

Beauty signals 2 things

Youth

Not preschool youth, sexually mature but also young

HealthSlide31

Beauty Universals

Beauty = Youth

Large eyes

Full lips

Smooth, tight skin

Beauty = Health

Absences of deformities

Clear eyes

Unblemished skin

Intact teeth

Average faceSlide32

Social Factors for Sex Differences

Some sex differences related to aggression and mate preference are universal across humans, show up in other mammals, and follow evolutionary

theory

These differences are likely innate in us

Other sex differences have origins that are less clear

Nature vs Nurture Sex DifferencesSlide33

Social Factors for Sex Differences

Babies are treated differently depending on the gender they are

So are we as adults

Studies have shown that when an email or job application are sent in, it matters whether the name on it is John Smith or Joan Smith

People have different expectations and different reactions to males vs females

Some of you may have experienced this if you have a name that could be taken as name of the opposite genderSlide34

Social Factors for Sex Differences

Gender self-segregation

Males segregate with other males

Females segregate with other females

This happens from age 6 – 12 (Middle Childhood!)

All boy groups may enhance and exaggerate a boy’s natural aggressiveness

All girls groups may enhance and exaggerate a girl’s natural non-aggressive behaviorSlide35

Social Factors for Sex Differences

Sex differences in empathy

Men are more violent (includes murder)

More testosterone in your body may make you less social

Boys are less empathetic than girls

Problems with empathy, with social cognition, are much more frequent in men than in womenSlide36

Social Factors for Sex Differences

Autism, Asperger’s Syndrome, conduct disorders, and psychopathy are predominately male

Some think there are also sex differences in the capacity to be able to do math and science

Larry Summers, former President of Harvard

Gave a speech saying there are “issues of aptitude” in women and that’s why there aren’t many women in the science and math

fieldsSlide37

Sexual Orientation

A large majority of men are sexually attracted to women

A large majority of women are sexually attracted to men

A minority of the population is homosexual – Why?

No one knows

Overall, people do not

choose

their sexual orientation

People who are gay are often discriminated against (sometimes extremely)

Some have no wish to be gay or may even think it’s morally wrong

This makes it implausible that their sexual orientation is a conscious choiceSlide38

Sexual Orientation

Some studies have shown that gay and straight individuals are different in their sexual and romantic fantasies before they hit puberty

Is being gay built in? Sort of

When you look between identical, fraternal, and adopted siblings, then yes, there is a genetic predisposition to homosexuality

But it can’t be all genetic

If I’m a gay identical twin, the odds that my twin is also gay are 50%

If it was TRULY genetic, the odds would be 100% since we’re clonesSlide39

Sexual Orientation

Homosexuality is an evolutionary mystery

It doesn’t seem to follow biological adaptation because it does not result in reproduction

According to evolutionary adaptation view, the genes that carry homosexuality would have been weeded out by now

Those carrying those genes wouldn’t have had offspring and the genes would have died with them

And that’s why the nature vs

nurture

argument to homosexuality is such a puzzle