Nature vs. Nurture: Can Evolutionary Psychology

and Cultural Anthropology be Reconciled?

Neither field explicitly studies free will.

Where is free will in evolutionary psychology

(EP) and cultural anthropology (CA)?

Nevertheless, both fields can accommodate compatibilist

and libertarian free will.

If nature and/or nurture influences but does not

determine our actions, we could still have libertarian

free will.

If nature and/or nurture determines our

actions (“determinism”), we still have

compatibilist free will so long as we do

not face coercion.

The rest of today’s class leaves aside questions of free

will, focusing instead on the potential conflict between

EP and CA.

EP: Evolution has left us with a human

nature.

CA: There is no such thing as human nature. Culture is

learned, and we start with a blank slate.

Smith’s attempted reconciliation of EP and CA

All people begin with the same human nature, which is a

product of evolution. Cultural differences then get layered

on top of this universal human nature.

A universal human nature leading to certain behaviors

under all circumstances?

Which would be more successful in promoting inclusive

fitness?

OR

A basic and universal human nature leading to behaviors

that depend upon the conditions in your society?

Incest Taboos

In animal studies using artificial insemination, parent/child

and brother/sister matings dramatically increase the

chances of unhealthy recessive traits.

However, in studies of both animals and humans, there is

only a relatively small increase in genetic abnormalities for

the offspring of first cousins, though the problems can

compound over many generations.

Smith’s attempted synthesis of EP and CA:

Humans have taboos against incest because avoiding sex

with close kin increased our ancestors’ inclusive fitness.

Unlike some other things that are illegal, most people have

no desire to break the brother/sister and parent/child

taboos, which points to an evolutionary origin.

For relationships other than brother/sister and parent/child,

culture can expand who is included within the taboos.

Data on incest taboos across different

societies

Among thousands of societies studied, none has ever

endorsed parent-child sexual relations. These relations

sometimes happen (through abuse and rape), but not with

social approval.

Only a handful of societies (ancient Egypt, Hawaii, the

Incas) have allowed brother-sister sexual relations, and that

was only for royalty. Brother-sister relations were taboo for

everyone else.

Beyond taboos on sex with people from the same

household, societies vary greatly.

In Western countries, cousin marriage used

to be common and is legal throughout

Europe. In the U.S., 19 states place no

restrictions on first-cousin marriage,

but the practice is generally frowned upon.

Some famous Westerners throughout history have married

their first cousins.

In many societies, cousins (sometimes cross-cousins,

sometimes parallel cousins) are the preferred marriage

partners.

Thus, a society’s norms about sex with people raised

outside the same household have cultural, not evolutionary,

origins.

rates of marriage, first or second cousins

Food Taboos

Which of the following would you order at a restaurant?

In countries as diverse as France, Japan,

and Kazakhstan, people eat horses.

Americans eat a lot of beef. Strict Hindus

in India do not eat beef at all, though

others do.

Jews who keep kosher may only

eat a land animal that has cloven hoofs

and chews its cud, fish with

fins and scales, and certain birds.

In the Trobriand Islands, only

lower-ranked clans can eat

shark and stingray.

Most food taboos have no clear linkage to

health. Most scholars trace their origins to

promoting group cohesion or marking a

person’s social status.

The diversity of food taboos across societies indicates that,

beyond dead and decaying animals and plants, culture has

free rein.

Food taboos might have an evolutionary origin, as a way

to avoid toxins. However, the only universal taboo is

against eating dead and decaying animals and plants.

Are the standards of physical attractiveness

universal?

· for some standards (those connected to

health, fertility, and genetic fitness in ancestral

environments), yes

· for other standards (those unconnected to health,

fertility, and genetic fitness in ancestral environments), no

Universal standards of attractiveness accepted

in evolutionary psychology:

facial symmetry

skin quality

in women: youth (child-bearing years)

in women: .7 ratio of waist to hips

in men: height, strength, deep voice, strong jaw.

No one has even tried to challenge the universality of

most of these. The fourth one, however, shows some

variability across societies.

Some standards of attractiveness that differ

across societies, thus indicating cultural

origins:

· Long necks for Padaung women in Burma

and Thailand.

· Small feet and broken arches for

upper class women before the early

part of the 20th century in China, which

justified foot-binding.

· Individuals differ on whether they prefer a certain

“look,” and some people have fetishes.

· Standards for body weight differ historically

and around the world.

Titian (1488-1576) Rubens (1577-1640)

· When food is relatively scarce, heavier people are

more attractive.

Possible combination of evolution (we are attracted to

signs of health and wealth) and culture (the characteristics

that indicate health and wealth depend on the context).

· Norms about pubic, leg, underarm, and facial

hair differ historically and around the world.

Beliefs and practices that are “merely cultural” are

nevertheless difficult to overturn.