A Case for Evolutionary Psychology

I have talked to two friends about how evolution played an important role in shaping human behavior.  Both opposed my claim and admitted that they do not believe in it.  I, too, have issues with evolutionary psychology, but for different reasons.  It is incorrect for you to assume that evolutionary psychology is wrong because you find it disturbing (e.g. leads to biological determinism, removes the divine mystery of emotions, etc).  You may think that this is obvious but you would be surprised by how often people buy into this faulty way of thinking.  I am rather unhappy with my college grades but that does not mean that I can think that those grades are not on my transcript.  In this post, I will make a case for why an educated human being should be familiar with evolutionary psychology and its results.  The truth is independent of your opinion of it.

The first thing we have to admit is that we are not born with equal abilities.  This is true physically, but also psychologically.  We know that depression, schizophrenia, alcoholism, and various other mental illnesses are highly heritable.  Intelligence (particularly linguistic proficiency and quantitative reasoning) is largely inherited but so is personality.  This has been confirmed most convincingly by twin studies.  Identical twins who share exactly the same genes are separated at birth and are studied when they meet again as adults.  These studies show that the personalities between the twins are stunningly identical.

(For more: http://en.wikipedia.org/wiki/Heritability_of_IQ

http://en.wikipedia.org/wiki/Twin_studies)

I will now discuss where evolutionary psychology is most commonly applied (which also happens to be where it is most controversial): human mating.  Even people who think that most of human behavior is conditioned by the environment will admit that the urge to have sex is innate.  However, there is no good reason for you to stop there.  Every species exhibits sexual behavior that is most certainly NOT learned.  In every sexualized species, the females are often pickier and less promiscuous than the males.  This is because there is a greater cost for a female to engage in sexual intercourse.  A male produces sperm very quickly and abundantly whereas a female only produces one egg per month.  The latter also bears the burden of carrying the developing fetus.  Any biologist will tell you this.  Why would this apply to all the other 5000+ mammalian species but not us?

What about emotions like jealousy?  Jealousy is essential for making sure that your genes are passed on.  This is especially important for men.  The advantage of being a woman is that you know that your children are yours.  This is not true for men.  Thus, men have to be wary to make sure their partners don’t cheat on them.  Men who lacked jealousy would end up raising other men's children and fail to pass on their genes.  Women need to be jealous too because they need to make sure their partners stay and support their children.  This is why men are more agitated by sexual infidelity and women are more troubled by emotional infidelity.

It helps to observe the mating behavior of the other great apes (chimpanzees, gorillas, and orangutans), our closest evolutionary cousins.  (Humans are considered great apes.)  Every adult, male gorilla, also known as a silverback, leads a harem of females and their children.  He is the only one who has sex with the females and attacks any male that tries to copulate with one of the former’s females.  If a silverback wishes to mate at all, he has to kill the silverback of the harem and all of the females’ infants.  This biologically rewires the females to be able to have the new silverback's offspring.  This also explains why gorillas have very small testes.  There is no sperm competition from other males because a female only has intercourse with one male at a time.  Male chimps have very large testes since they frequently participate in group sex.  Interestingly, men’s testes are somewhere in between (not very large but also not very small).

Arguably, male orangutans demonstrate the most disturbing sexual behavior.  Some males are very large, approximately twice the size of females, and females find them highly attractive.  Females willingly have sex with these large males and will even compete for their attention and resources.  However, there are also much smaller males that are no bigger than the females.  They execute a different strategy.  These small males sneak up behind females and forcibly penetrate them.  We know that the females are not willing because they scream, run around, and try to push the males off.  Shockingly, these male orangutans occasionally try to rape women (including Julia Roberts).

For now, I would like to end with the following note.  None of this information morally justifies any human behavior.  If some men have built-in, biological impulses to rape women, that does not exonerate them from punishment.  If these men cannot do anything about it, then they should be quarantined from mainstream society.  It is very difficult to unlearn innate behavior as Ted Haggard, Exodus International, and other “ex-gays” will admit.  I will write more evolutionary psychology posts in the future.  Feel free to comment, correct, or question below.