Transcript The Matting Mind-How Sexual Choice Shaped the Evolution of

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
• The variable trait must be heritable
• Females must develop a preference for that trait;
it doesn’t matter why the trait was preferred.
• A species must be polygamous
The Result of Runaway Selection
• 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.
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.
• This was a variable trait.
• Females develop a preference for this trait and they
were able to pass it on to their offspring.
• Humans 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.
• 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.
Solution to Problem #1
• 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.
• 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
selection
• 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.
Solution to Problem #2
• For long term relationships men and women are
equally choosey.
• Men and women are subject to equal pressure
for sexual selection.
• 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 two
• Mutual choice isn’t compatible with runaway
selection.
• 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)
• 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.
• Wilde 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.
• 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
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Reciprocity
•
•
–
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.
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.
Problems
•
•
Kinship and reciprocity have a difficulty explaining charity to non-relatives.
Neither explains moral leadership, romantic generosity, sympathy, sexual
fidelity, or sportsmanship.
Biologists and Scientists Agree Human
Morality Must Be Taught
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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.
Tessman: Argues Sexual Selection
Shapes Morality
– Mate choice could be the single most
powerful moral filter from one generation to
the next.
• Vegetarian 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.
Donating to Charities-Selfish or
Really Helpful?
• “Charity Events” are excuses for parties
• “Charity Work” shows how generosity is used as
an inefficient display rather than an efficient
resource transfer device
• Token of appreciation is necessary
• Why do people contribute?
Why Men Tip Better Than Women
• Men have more money to spare
• John Rockefeller
Male Generosity in Courtship
• Males incur high costs
• Human courtship is a social contract offered in
exchange for sex
• Romantic gifts are useless to women, but
expensive for men
Sexual Fidelity and Romantic Love
• Humans are less likely to cheat than other
animals
• Romantic love vs. Sexual Love
Sexual Selection and Nietzsche
• “Morality of the Herd” includes prudence,
conscience, equality, submission, etc.
• Core 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.
•
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 considered
• Miller’s final conclusion on brain size
• What’s the relevance of leadership to the
subject?
• What did these 2 chapters have in common?
Questions??