What Motivates Us: Sex

1. What Motivates Us: Sex Intro to psych 4/10/14

2. 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 different

3. 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 evolved

4. 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 & consequences

5. 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?

6. 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 Pinker

7. 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 infection

8. 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?

9. 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 Dawkins

10. 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 of

11. 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)

12. 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?

13. 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 cell

14. 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 success

15. 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 mates

16. Basic Sex Ed http://www.arkive.org/superb-bird-of-paradise/lophorina-superba/video-99a.html

17. 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 evolve

18. 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 size

19. 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 adults

20. 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 existed

21. 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”

22. 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 again

23. 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)

24. 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 together

25. Sex Differences Among Humans

26. 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”

27. 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 promiscuity

28. 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 from

29. Sex Differences Among Humans • What about sexual attractiveness? • People are asked “Who do you want to be with/marry/have as a partner?” • Females & Males: kindnessand intelligence • Females • More focus on power and status • High interest in investing in children • Males • More focus on the ability to have children

30. Beauty • Beauty signals 2 things • Youth • Not preschool youth, sexually mature but also young • Health

31. Beauty Universals • Beauty = Youth • Large eyes • Full lips • Smooth, tight skin • Beauty = Health • Absences of deformities • Clear eyes • Unblemished skin • Intact teeth • Average face

32. 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 Differences

33. 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 gender

34. 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 behavior

35. 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 women

36. 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 fields

37. 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 choice

38. 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 clones

39. 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