BOOK SUMMARY: Sex at Dawn
Rather than review this book, I'd like to share what I understand of it's core theses. I'm not going to defend them nor present the variety of supporting arguments; read the book! But I think a terse summary of the points (and yes I'm going to miss some or even "a lot", sorry) presents a Very Interesting Picture. Here we go:
- For 95% of human existance as "humans" (the period of human history prior to the rise of agriculture), people lived in small (100-150 person) nomadic hunting/gathering groups.
- Possessions in such groups were next to none; they moved frequently. There was little to no "ownership" of anything.
- These groups were very well fed and suffered far less from malnutrition and/or starvation than mankind has since the switch to agriculture.
- Average lifespan once childhood was survived was a very robust 62 or more. Many children died and infanticide was probably common. The short lifespan commonly attributed to prehistory humans is due to averages skewed by high child death rates (average lifespan at birth, vs. average lifespan for someone making it to adulthood).
- The people were substantially taller than we commonly believe: 5'9" was an average height. Mankind shrunk in size dramatically after the agrarian shift, and is still "recovering". In some areas of the world human height averages still haven't reached prehistory norms.
- Pair bonding was not generally practiced. The culture was one of sharing, of everything.
- Women engaged in sex with multiple men, frequently. Men engaged in sex with multiple women, frequently.
- The basis of evolution was "sperm competition", rather than externalized "the better man gets the woman and thus the better man's attributes win out".
- Many many physical and social elements enabled (or came about to enable) sperm competition.
- Men's penis's are designed to create suction in the female's vagina to suck out sperm left by previous partners. The head of the penis decreases on male orgasm to release the suction, so the male's sperm deposit stays in place.
- Women cry out far more during sex then men to signal to the surrounding men that she's ready, available and willing.
- Women have multiple orgasms to encourage them to take multiple men, thereby enabling the sperm competition.
- Human male penis's are relatively huge (to body size). Why? Because with sperm competition, larger (width and depth) penis will "win out" more often by depositing the sperm more deeply, and suck out the competitive sperm more reliably.
- Men's sexual "style" of quick sex followed by a refractory period helps to enable a system of the women taking on multiple partners and collecting a wide variety of sperm. Women's sexual "style" of warming up more slowly but then having the ability and desire to go and go is the other side of this asymmetry.
- We are not the like apes, where a single dominant male "gets the ladies". That has led the apes to have huge male size (the biggest is the winner and passes on his traits.) It's also led to the ape having a relatively small penis, about 1". Once he wins with his size, he has no competition with his penis. No genetic/sperm competition drove larger penis size in apes.
- Human society's general failure around monogamous relationships is fundamentally due to human's not being fundamentally monogamous.
- Men get eroticized by seeing/hearing other men sexing a woman. This is validated both physically in a variety of ways, and socially by such evidence as the huge disproportion of interest in multi-men/single-woman porn vs. single-man/multi-women porn. Also, this explains the relatively common desire of married men to have their wife engage in outside sex (the "cuckold" phenomena). The reason for this erotic response is to encourage multiple inseminations in a woman by different men to create sperm competition.
- The hunter/gathering social groups were generally peaceful, as the world was extraordinarily sparsely populated, and there was no need for competing with neighboring groups. Either there was enough for both, or one would move to another area. Additionally, fights between men for access to women were unusual, as all men generally had access to all women within the group. Hoarding in both the physical domain (food) and sexual domain was taboo.
- The multi-partner sexual culture, as with bonobos, helped to create and support social bonds, relax the males, and generally helped ensure social order.
- Human female breasts are far, far larger than necessary for milk production. Their function seems to be to generally attract "a lot" of males, as well as signaling fertility.
- Human's engage in sex far more often and for much longer time periods than any other species. Sex is relatively speaking a major focus of time and attention for us.
- External male testes represent a major evolutionary compromise. They are horrible from a self-protection perspective, so why are they there? They enable men to have lots of ready to go sperm, and enable the ability to have effective (high sperm count delivery) much more frequently.
- Male testes DNA are highly flexible re: adaptation. Prehistory males probably had much larger testes that we have today. Testes size in humans are shrinking very very rapidly, along with sperm counts by volume. Why? The effect of switching to monogamy. With the prehistorical multi-sex partner culture, the "best" sperm won, so men evolved towards more sperm via larger testes. With monogamy, less effective delivery systems win because they have no competition. Monogamy is literally making men's balls shrink generation to generation.
- Women as highly sexual and promiscuous beings is highly contrary to the social structures that arose out of the switch to agriculture and the rise of patriarchal culture. The result has been and continues to be the repression of women in general, and the repression of women's sexuality specifically.
What strike me about this is it's incredible "self consistency", even without considering all the specific supporting evidence for each individual point.
What it says about us is pretty amazing too.
I apologize again if the list above is incomplete or not 100% accurate to the book; correct away if so inclined.