The Mating Mind-How Sexual Choice Shaped the Evolution of Human Nature By Geoffrey Miller Presented By : Kristin McCoy Laura Oden Anne Perez

Chapter 3: The Runaway Brain

Runaway Selection What is needed for it to work? A variable trait A variable trait The variable trait must be heritableThe variable trait must be heritable Females must develop a preference for that trait; it doesn’t matter why the trait was preferred.Females must develop a preference for that trait; it doesn’t matter why the trait was preferred. A species must be polygamousA species must be polygamous

The Result of Runaway Selection The offspring of the females who select that trait will inherit the trait.The offspring of the females who select that trait will inherit the trait. Consequently the daughters will also develop a preference for that trait. Sons who inherit the trait will pass the desire for said trait to their daughters as well.Consequently the daughters will also develop a preference for that trait. Sons who inherit the trait will pass the desire for said trait to their daughters as well.

Runaway and the human brain One could argue that runaway selection could explain human brain size. The trait that humans selected for was creative intelligence.The trait that humans selected for was creative intelligence. This was a variable trait.This was a variable trait. Females develop a preference for this trait and they were able to pass it on to their offspring.Females develop a preference for this trait and they were able to pass it on to their offspring. Humans used to be moderately polygamousHumans used to be moderately polygamous

Problem #1 with Runaway Selection and the Human Brain Run away selection selects for a trait and modifies it greatly over many generations.Run away selection selects for a trait and modifies it greatly over many generations. The human brain grew too slowly for runaway selection to explain it. The human brain grew too slowly for runaway selection to explain it. Runaway selection produces sex differences. If it did work, males would have a three pound brain and females would have a one pound brain.Runaway selection produces sex differences. If it did work, males would have a three pound brain and females would have a one pound brain.

Solution to Problem #1 Remember females are the one selecting for the trait.Remember females are the one selecting for the trait. There is an overlap of creative intelligence and the part of the brain used for judging and selecting for creative intelligence.There is an overlap of creative intelligence and the part of the brain used for judging and selecting for creative intelligence. Female brain would evolve creative intelligence themselves so they could develop expectation about behavior and judge it.Female brain would evolve creative intelligence themselves so they could develop expectation about behavior and judge it.

Problem #2 Females select a specific trait in runaway selectionFemales select a specific trait in runaway selection The way that it was previously stated means that female only evolved intelligence as an effect of men evolving intelligence.The way that it was previously stated means that female only evolved intelligence as an effect of men evolving intelligence. Females couldn’t develop a heightened expectation for a trait if they came about it latently.Females couldn’t develop a heightened expectation for a trait if they came about it latently.

Solution to Problem #2 For long term relationships men and women are equally choosey.For long term relationships men and women are equally choosey. Men and women are subject to equal pressure for sexual selection.Men and women are subject to equal pressure for sexual selection. Mental capacity and creative intelligence could evolve equally in both two sexes.Mental capacity and creative intelligence could evolve equally in both two sexes.

The Final Answer There is an error in logic to the solution to problem twoThere is an error in logic to the solution to problem two Mutual choice isn’t compatible with runaway selection.Mutual choice isn’t compatible with runaway selection. Therefore pure runaway selection can not explain creative intelligence.Therefore pure runaway selection can not explain creative intelligence.

Chapter 9: The Virtues of Good Breeding

Human Morality- Behavior That Displays Good Moral Character –Most evolutionary psychologists say human morality is based on Nepotism (kindness to blood relatives)Nepotism (kindness to blood relatives) Reciprocity (kindness to those who may reciprocate)Reciprocity (kindness to those who may reciprocate)

Miller says Human Morality is the Direct Result of Sexual Selection –Ancestors picked kind, generous, helpful, and fair mates. Buss’s study showed “kindness” was the most important feature desired by both men and women in the 37 cultures studied.Buss’s study showed “kindness” was the most important feature desired by both men and women in the 37 cultures studied. Wilde put his finger on an evolutionary pressure for morality that has not yet been received as sufficient attention in evolutionary psychology: good moralWilde put his finger on an evolutionary pressure for morality that has not yet been received as sufficient attention in evolutionary psychology: good moral character is sexually attractive & romantically inspiring. A sexual selection perspective allows us to explain sympathy, agreeableness, moral leadership, good parenting, etc.

Apathy as the Evolutionary Norm Animals from all over the world get out of each other’s way.Animals from all over the world get out of each other’s way. Darwin: Most violent competition happens within animals of the same species who are competing for the same resources and the same mates.Darwin: Most violent competition happens within animals of the same species who are competing for the same resources and the same mates.

Evolutionary Biology Rules Demand We Find a Hidden Genetically Selfish Benefit to our Altruism –Kinship It tends to help other copies of the same gene to prosper, Generosity to blood relatives is actually genetic selfishness.It tends to help other copies of the same gene to prosper, Generosity to blood relatives is actually genetic selfishness. Many think that the adaptations for kindness to kin may have been important building blocks for kindness toward non-kin.Many think that the adaptations for kindness to kin may have been important building blocks for kindness toward non-kin. –Reciprocity Benefit by being nice to one another if they interact often enough to build up trust.Benefit by being nice to one another if they interact often enough to build up trust. Alternate with giving and receiving; whole sequence is mutually beneficial.Alternate with giving and receiving; whole sequence is mutually beneficial. –Problems Kinship and reciprocity have a difficulty explaining charity to non-relatives.Kinship and reciprocity have a difficulty explaining charity to non-relatives. Neither explains moral leadership, romantic generosity, sympathy, sexual fidelity, or sportsmanship.Neither explains moral leadership, romantic generosity, sympathy, sexual fidelity, or sportsmanship.

Biologists and Scientists Agree Human Morality Must Be Taught –All organisms must evolve due to the idea that they are promoting the replication of their own genes at the expense of other genes. –The evolution selfishness of the gene was seen as leading to selfish humans. Dawkins says we are born selfish –Human kindness is an adaptation to be explained so the goal is to find the hidden evolutionary benefits of human kindness.

Argues Sexual Selection Shapes Morality Tessman: Argues Sexual Selection Shapes Morality –Mate choice could be the single most powerful moral filter from one generation to the next. Vegetarian exampleVegetarian example

Equilibrium Selection --Game theory: where your payoff for doing something depends not only on what you do, but also on what other people do. –An equilibrium selection is the gradual process by which an equilibrium becomes established for a particular game. –Equilibrium: a set of strategies, one for each player that has a simple property. The property that no one player has an incentive to switch to different strategies, given what the other players is already doing. 1. Ex: Americans drive on the right side, British drive on the left side, and Bangalore choose daily which side they drive on.1. Ex: Americans drive on the right side, British drive on the left side, and Bangalore choose daily which side they drive on.

Donating to Charities-Selfish or Really Helpful? “Charity Events” are excuses for parties“Charity Events” are excuses for parties “Charity Work” shows how generosity is used as an inefficient display rather than an efficient resource transfer device“Charity Work” shows how generosity is used as an inefficient display rather than an efficient resource transfer device Token of appreciation is necessaryToken of appreciation is necessary Why do people contribute?Why do people contribute?

Why Men Tip Better Than Women Men have more money to spareMen have more money to spare John RockefellerJohn Rockefeller

Male Generosity in Courtship Males incur high costsMales incur high costs Human courtship is a social contract offered in exchange for sexHuman courtship is a social contract offered in exchange for sex Romantic gifts are useless to women, but expensive for menRomantic gifts are useless to women, but expensive for men

Sexual Fidelity and Romantic Love Humans are less likely to cheat than other animalsHumans are less likely to cheat than other animals Romantic love vs. Sexual LoveRomantic love vs. Sexual Love

Sexual Selection and Nietzsche “Morality of the Herd” includes prudence, conscience, equality, submission, etc.“Morality of the Herd” includes prudence, conscience, equality, submission, etc. Core elements of pagan virtuesCore elements of pagan virtues *virtue as force *virtue as seduction *virtue as etiquette

Conclusion Without sexual selection, generosity to unrelated individuals unable to reciprocate would be very unlikely to evolve.Without sexual selection, generosity to unrelated individuals unable to reciprocate would be very unlikely to evolve. With sexual selection, such generosity can evolve easily as long as the capacity for generosity reveals the giver’s fitness.With sexual selection, such generosity can evolve easily as long as the capacity for generosity reveals the giver’s fitness.

What Confused/Interested Us Difference between prostitution and male gift giving-how long does it take to be consideredDifference between prostitution and male gift giving-how long does it take to be considered Miller’s final conclusion on brain sizeMiller’s final conclusion on brain size What’s the relevance of leadership to the subject?What’s the relevance of leadership to the subject? What did these 2 chapters have in common?What did these 2 chapters have in common?

Questions??