We shifted a lot of the more scientific discussion to the endnotes of Sex at Dawn. This seemed like a good way to include the sorts of information students and other specialized readers would need while not overloading more casual readers less concerned with sources and methodological issues. Since many of the papers we cited are available on line, we’ve got lots of links in the endnotes. Here you’ll find a regularly updated version of that part of the book. Please let us know if you come across any dead links, either here or in the book itself. We’ll add new references (stuff that’s come out since publication) at the end of the relevant sections.
Introduction
1. Maybe as recently as 4.5 million years ago. For a recent review of the genetic evidence, see Siepel (2009).
2. de Waal (1998), p. 5.
3. Some of these numbers are reported in McNeil et al. (2006) and Yoder et al. (2005). The hundred billion figure comes from http:// www.latimes.com/news/nationworld/nation/la-fg-vienna-porn25- 2009mar25,0,7189584.story.
4. See “Yes, dear. Tonight again.” Ralph Gardner, Jr. The New York Times (June 9, 2008): http://www.nytimes.com/2008/06/08/fashion/08nights.html
5. Full disclosure: Murdoch also owns HarperCollins, the publisher of this book.
6. Diamond (1987).
7. Such relationships would have been among many group-identity-boosting techniques, including participation in group bonding rituals still common to shamanistic religions characteristic of foraging people. Interestingly, such collective-identity-affirming rituals are often accompanied by music (which—like orgasm—releases oxytocin, the hormone most associated with forming emotional bonds). See Levitin (2009) for more on music and social identity.
8. The precise timing of this shift has recently been called into question. See White and Lovejoy (2009).
9. For more on the sharing-based economies of foragers, see Sahlins (1972), Hawkes (1993), Gowdy (1998), Boehm (1999), or Michael Finkel’s National Geographic article on the Hadza, available here: http://ngm.nationalgeographic.com/2009/12/hadza/finkel-text.
10. Mithen (2007), p. 705.
11. Taylor (1996), pp. 142–143. Taylor’s book is an excellent archaeological account of human sexual origins.
Part I: On the Origin of the Specious
Chapter 1: Remember the Yucatán!
1. This account comes from Todorov (1984), but Todorov’s version of events is not universally accepted. See http://www.yucatantoday.com/ culture/esp-yucatan-name.htm, for example, for a review of other etymologies (in Spanish).
2. From the FDA’s Macroanalytical Procedures Manual—Spice Methods. Accessed online at: http://www.fda.gov/Food/ScienceResearch/ LaboratoryMethods/MacroanalyticalProceduresManualMPM/ ucm084394.htm.
Chapter 2: What Darwin didn’t Know About Sex
1. Originally published in Daedalus, Spring 2007. Article can be found here: http://www.redorbit.com/news/science/931165/challenging_darwins_theory_of_sexual_selection/index.html. For more of her uniquely informed view of sexual diversity in nature, see Roughgarden (2004). For her deconstruction of self-interest as the engine of natural and sexual selection, see Roughgarden (2009). For more on homosexuality in the animal world, see Bagemihl (1999).
2. http://www.advicegoddess.com/ag-column-archives/2006/05.
3. Not everyone would agree, of course. When Darwin’s brother Erasmus first read the book, he found Charles’s reasoning so compelling that he wasn’t bothered by the lack of evidence, writing, “If the facts won’t fit in, why so much the worse for the facts is my feeling.” For a thorough (but reader-friendly) look at how Darwin’s Victorianism affected his own and subsequent science, see Hrdy (1996).
4. Darwin (1871/2007), p. 362.
5. Pinker (2002), p. 253.
6. Fowles (1969), pp. 211-212.
7. Houghton (1957). Quoted in Wright (1994), p. 224.
8. Quoted in Richards (1979), p. 1244.
9. Writing in Scientific American Online (February 2005, p. 30), science historian Londa Schiebinger explains: “Erasmus Darwin . . . did not limit sexual relations to the bonds of holy matrimony. In his “Loves of the Plants” (1789), Darwin’s plants freely expressed every imaginable form of heterosexual union. The fair Collinsonia, sighing with sweet concern, satisfied the love of two brothers by turns. The Meadia—an ordinary cowslip—bowed with ‘wanton air,’ rolled her dark eyes and waved her golden hair as she gratified each of her five beaux. . . . Darwin may well have been using the cover of botany to propagandize for the free love he practiced after the death of his first wife.”
10. From Hrdy (1999b).
11. Raverat (1991).
12. Desmond and Moore (1994), p. 257. Also, see Wright (1994) for excellent insights into Darwin’s thought process and family life.
13. The Flintstones occupies a unique place in American cultural history. It was the first prime-time animated series for adults, ABC’s first series to be shown in color, the first prime-time animated series to last more than two seasons (not matched until The Simpsons in 1992), and the first animated program to show a man and woman in bed together.
14. Lovejoy (1981).
15. Fisher (1992), p. 72.
16. Ridley (2006), p. 35.
17. See, for example, Steven Pinker’s assertion that human societies have become progressively more peaceful through the generations (discussed in detail in Chapter 13).
18. Wilson (1978), pp. 1–2.
19. A view Steven Pinker resuscitated decades later, long after more nuanced positions had become prevalent.
20. See, for example, Thornhill and Palmer (2000).
21. “A Treatise on the Tyranny of Two,” New York Times Magazine, October 14, 2001. You can read the essay online at http://www.nytimes.com/2001/10/14/magazine/14AGAINSTLOVE.html
22. Quoted in Flanagan (2009).
23. Real Time with Bill Maher (March 21, 2008). Ironically, the panelist who suggested “moving on” was Jon Hamm who, at the time, played a serial womanizer on TV’s Mad Men.
24. For more on Morgan’s life and thought, see Moses (2008).
25. Morgan (1877/1908), p. 418, 427.
26. Darwin (1871/2007), p. 360.
27. Morgan (1877/1908), p. 52.
28. Dixson (1998), p. 37.
Chapter 3: A Closer Look at the Standard Narrative of Human Sexual Evolution
1. With apologies to John Perry Barlow, author of “A Ladies’ Man and Shameless.” At: http://www.nerve.com/personalEssays/Barlow/ shameless/index.asp?page=1.
2. Wilson (1978), p. 148
3. Pinker (2002), p. 252.
4. Barkow et al. (1992), p. 289.
5. Barkow et al. (1992), pp. 267–268.
6. Acton (1857/62), p. 162.
7. Symons (1979), p. vi.
8. Bateman (1948), p. 365.
9. Clark and Hatfield (1989).
10. Wright (1994), p. 298.
11. Buss (2000), p. 140.
12. Wright (1994), p. 57.
13. Birkhead (2000), p. 33.
14. Wright (1994), p. 63.
15. Henry Kissinger—just our opinion. Nothing personal.
16. Wright (1994), pp. 57–58.
17. Symons (1979), p. v.
18. Fisher (1992), p. 187.
Chapter 4: The Ape in the Mirror
1. See Caswell et al. (2008) and Won and Hey (2004). Rapid advances in genetic testing have reopened the debate over the timing of the chimp/bonobo split. We use the widely accepted estimate of 3 million years, though it may turn out to have occurred less than a million years ago.
2. This account from de Waal and Lanting (1998).
3. Harris (1989), p. 181.
4. Symons (1979), p. 108.
5. Wrangham and Peterson (1996), p. 63.
6. Sapolsky (2001), p. 174.
7. Table based on de Waal (2005a) and Dixson (1998).
8. Stanford (2001), p. 116.
9. Berman (2000), pp. 66–67.
10. Dawkins (1976), p. 3.
11. http://www.edge.org/3rd_culture/woods_hare09/woods_hare09_ index.html.
12. de Waal (2005), p. 106.
13. Theroux (1989), p. 195.
14. Pusey (2001), p. 20.
15. Stanford (2001), p. 26.
16. McGrew and Feistner (1992), p. 232.
17. de Waal (1995).
18. de Waal and Lanting (1998), p. 73.
19. de Waal (2001a), p. 140.
20. The quote appears here: http://primatediaries.blogspot.com/2009/03/bonobos-in-garden-of-eden.html.
21. Fisher (1992), p. 129.
22. Fisher (1992), pp. 129–130.
23. Fisher(1992). These quotes are all taken from an endnote on page 329.
24. Fisher (1992), p. 92.
25. Fisher (1992), pp. 130–131.
26. de Waal (2001b), p. 47.
27. de Waal (2005), pp. 124–125.
28. A true man of science, de Waal was kind enough to review and critique parts of this book, including sections where we disagree with some of his views.
29. The information in this chart is taken from various sources (Blount, 1990; Kano, 1980 and 1992; de Waal and Lanting, 1998; Savage- Rumbaugh and Wilkerson, 1978; de Waal, 2001a; de Waal, 2001b).
Relevant research published after Sex at Dawn.
1. Paternity and relatedness in wild chimpanzee communities. Authors: Linda Vigilant, Michael Hofreiter, Heike Siedel, and Christophe Boesch. This paper questions the high levels of extra-group mating other researchers have reported among wild chimps, as well as the centrality of male coalitions in chimp social organization, suggesting that male-female interactions are more important than previously believed.
Part II: Lust in Paradise (Solitary)
Chapter 5: Who Lost What in Paradise?
1. For readers interested in further understanding how and why the shift from foraging to cultivation happened, Fagan (2004) and Quinn (1995) are both great places to start.
2. Cochran and Harpending (2009) point out some of these parallels: “In both [domesticated] humans and domesticated animals,” they write, “we see a reduction in brain size, broader skulls, changes in hair color or coat color, and smaller teeth.” (p. 112.)
3. Anderson is quoted in “Hellhole,” by Atul Gawande in The New Yorker, March 30, 2009. The article is very much worth reading for its
examination of whether solitary confinement is so anti-human that it qualifies as torture. Gawande concludes it clearly does, writing, “Sim- ply to exist as a normal human being requires interaction with other people.”
4. Jones et al. (1992), p. 123.
5. Although only humans and bonobos appear to have sex throughout
the menstrual cycle, both chimps and some types of dolphins seem to share our predilection for engaging in sex for pleasure, as opposed to reproduction alone.
6. These tidbits come from Ventura’s wonderful essay on the origins of jazz and rock music, “Hear That Long Snake Moan,” published in Ventura (1986). The book is out of print, but you can access this essay and other writing at Ventura’s website: http://www.michaelventura. org/. The Thompson material can be found both in Ventura’s essay and in Thompson (1984).
Chapter 6: Who’s Your Daddies?
1. Harris (1989), p. 195.
2. Beckerman and Valentine (2002), p. 10.
3. Beckerman and Valentine (2002), p. 6.
4. Kim Hill is quoted in Hrdy (1999b), pp. 246–247.
5. Among the Bari people of Colombia and Venezuela, for example, researchers found that 80 percent of the children with two or more socially recognized fathers survived to adulthood, whereas only 64 percent of those with one official father made it that far. Hill and Hurtado (1996) reported that among their sample of 227 Aché chil- dren, 70 percent of those with only one recognized father survived to age ten, while 85 percent of those with both a primary and secondary father made it that far.
6. The quote is from an article by Sally Lehrman posted on AlterNet .org. Available at http://www.alternet.org/story/13648/?page=entire.
7. Morris (1981), pp. 154–156.
8. In Beckerman and Valentine (2002), p. 128.
9. See Erikson’s chapter in Beckerman and Valentine (2002).
10. Williams (1988), p. 114.
11. Caesar (2008), p. 121.
12. Quoted in Sturma (2002), p. 17.
13. See Littlewood (2003).
14. At this point, naysayers will point out that Margaret Mead’s famous claims of South Seas libertines were debunked by Derek Freeman (1983). But Freeman’s debunking has been debunked as well, thus leaving Mead’s original claims, what, rebunked? Hiram Caton (1990) and others have argued, quite compellingly, that Freeman’s relentless attacks on Mead were likely motivated by a psychiatric disorder that also led to several paranoid outbursts of such intensity that he was forcibly removed from Sarawak by Australian diplomatic officials. The general consensus in the anthropological community seems to be that it’s unclear to what extent, if any, Mead’s findings were mistaken. Freeman’s purported debunking took place after decades of Christian indoctrination of Samoans, so it should surprise no one if the stories he heard differed significantly from those told to Mead half a century earlier. For a brief review, we recommend Monaghan (2006).
15. Ford and Beach (1952), p. 118.
16. Small (1993), p. 153.
17. de Waal (2005), p. 101.
18. Morris (1967), p. 79.
19. http://primatediaries.blogspot.com/2007/08/forbidden-love.html.
20. Kinsey (1953), p. 415.
21. Sulloway (1998).
22. For a review of other mammals that practice sharing behavior, see Ridley (1996) and Stanford (2001).
23. Bogucki (1999), p. 124.
24. Knight (1995), p. 210.
25. The extent to which ovulation truly is hidden in humans is not as settled a matter as many authorities claim. There is good reason to beieve that olfactory systems are still able to detect ovulation in women and that such systems are significantly atrophied when compared with those of ancestral humans. See, for example, Singh and Bronstad (2001). Furthermore, there is reason to believe that women advertise their fertility status via visual cues such as jewelry and changes in facial attractiveness. See, for example, Roberts et al. (2004).
26. Daniels (1983), p. 69.
27. Gregor (1985), p. 37.
28. Crocker and Crocker (2003), pp. 125–126. 29. Wilson (1978), p. 144.
Chapter 7: Mommies Dearest
1. Pollock (2002), pp. 53–54.
2. The quote is taken from an interview by Sarah van Gelder, “Remembering Our Purpose: An Interview with Malidoma Somé,” In Context: A Quarterly of Humane Sustainable Culture, vol. 34, p. 30 (1993). Available online at http://www.context.org/ICLIB/IC34/Some.htm.
3. Hrdy (1999), p. 498.
4. Darwin (1871), p. 610.
5. Leacock (1981), p. 50.
6. http://www.slate.com/id/2204451/.
7. Erikson (2002), p. 131.
8. Chernela (2002), p. 163.
9. Lea (2002), p. 113.
10. Chernela (2002), p. 173.
11. Morris (1998), p. 262.
12. Malinowski (1962), pp. 156–157.
13. See Sapolsky (2005).
14. Drucker (2004).
15. Even Jean-Jacques Rousseau, poster-boy for the Romantic ideal of the Noble Savage, made use of these baby disposals. In 1785, Benjamin Franklin
visited the hospital where Rousseau had deposited his five illegitimate children and discovered a mortality rate of 85 percent among the babies there (“Baby Food,” by Jill Lepore, in The New Yorker, January 19, 2009).
16. McElvaine (2001), p. 45.
17. Betzig (1989), p. 654.
Chapter 8: Making a Mess of Marriage, Mating, and Monogamy
1. As we write this, Tiger Woods is being accused of having “slept with” more than a dozen women in cars, parking lots, on sofas. . . . Are we to think he’s a narcoleptic?
2. de Waal (2005), p. 108.
3. Trivers’s paper is seen as the foundational text in establishing the importance of male provisioning (investment) as a crucial factor in female sexual
selection, among other things. It’s well worth a read if you want a deeper understanding of the overall development of evolutionary psychology.
4. Ghiglieri (1999), p. 150.
5. Small (1993), p. 135.
6. Roughgarden (2007). Available online: http://www.redorbit.com/news/science/931165/challenging_darwins_theory_of_sexual_selection/index.html.
7. The New Yorker, November 25, 2002.
8. Cartwright’s article is available here: http://www.pbs.org/wgbh/aia/part4/4h3106t.html.
9. Symons (1979), p. 108.
10. Valentine (2002), p. 188.
11. Article by Souhail Karam, Reuters, July 24, 2006.
12. The New Yorker, April 17, 2007.
13. Vincent of Beauvais Speculum doctrinale 10.45.
14. Both from Townsend and Levy (1990b).
Chapter 9: Paternity Certainty: the Crumbling Cornerstone of the Standard Narrative
1. Edgerton (1992), p. 182.
2. In Margolis (2004), p. 175.
3. Pollock (2002), p. 53.
4. For more on the deep connections between a society’s levels of violence and its eroticism, see Prescott (1975).
5. Quoted in Hua (2001), p. 23.
6. Namu (2004), p 276. For an excellent look at Mosuo culture, check out PBS Frontline World, “The Women’s Kingdom,” available at www.pbs.org/frontlineworld/rough/2005/07/introduction_to.html.
7. Namu (2004), p. 69.
8. Namu (2004), p. 8.
9. This sacred regard for each individual’s autonomy is characteristic of foragers, too. For example, when Michael Finkel visited the Hadza recently in Tanzania, he reported, “the Hadza recognize no official leaders. Camps are traditionally named after a senior male . . . but this honor does not confer any particular power. Individual autonomy is the hallmark of the Hadza. No Hadza adult has authority over any other.” (National Geographic, December 2009.)
10. Hua (2001), pp. 202–203.
11. Namu (2004), pp. 94–95.
12. China’s Kingdom of Women, Cynthia Barnes. Slate.com (November 17, 2006): http://www.slate.com/id/2153586/entry/2153614.
13. Goldberg (1993), p. 15.
14. (Photo: Christopher Ryan.) When I saw this old woman, I knew her face contained the feminine strength and humor I was hoping to convey in a photo. I gestured to ask if it would be all right to take her picture. She agreed, but asked me to wait, and immediately started calling. These two little girls (granddaughters? Great- granddaughters?) came running. Once she had them in her arms, she gave me the go-ahead to take the shot.
15. The book was published in 2002, while Goldberg’s came out almost a decade earlier, but all of Sanday’s work on the Minangkabau, including the paper Goldberg cites, argues against his position—a point certainly deserving of mention.
16. Source: http://www.eurekalert.org/pub_releases/2002-05/uop-imm050902.php.
17. Source: www.eurekalert.org/pub_releases/2002-05/uop-imm050902 .php.
18. Most of these quotes are from an article by David Smith that appeared in The Guardian, September 18, 2005, available online at http://www.guardian.co.uk/uk/2005/sep/18/usa.filmnews, or Stephen Holden’s review in The New York Times, June 24, 2005, available online at http://movies.nytimes.com/2005/06/24/movies/24peng.html?_r=2.
19. The San Diego Union-Tribune: “Studies Suggest Monogamy Isn’t for the Birds—or Most Creatures,” by Scott LaFee, September 4, 2002.
20. “Monogamy and the Prairie Vole,” Scientific American online issue, February 2005, pp. 22–27.
21. Things have become a bit more muddled since Insel said that. More recently, Insel and others have been working on trying to discover the hormonal correlations underlying the fidelity or lack thereof among prairie, montane, and meadow voles. As reported in the October 7, 1993 issue of Nature, Insel and his team found that vasopressin, a hormone released during mating, seemed to trigger protective, nest- guarding behavior in some species of male voles, but not others, lead- ing to speculation about “monogamy genes.” See http://findarticles .com/p/articles/mi_m1200/is_n22_v144/ai_14642472 for a review. In 2008, Hasse Walum of the Karolinska Institute in Sweden found that a variation in the gene called RS3 334 seemed to be associated with how easily men bonded emotionally with their partners. Most interestingly, the gene appears to have some association with autism as well. The reference for Walum’s paper is Proceedings of the National Academy of Sciences, DOI: 10.1073pnas.0803081105. A news article summarizing the findings is online at http://www.newscientist.com/ article/dn14641-monogamy-gene-found-in-people.html.
Chapter 10: Jealousy: a Beginner’s Guide to Coveting thy Neighbor’s Spouse
1. Darwin (1871/2007), p. 184.
2. Hrdy (1999b), p. 249.
3. Known to historians as The Wicked Bible or The Adulterous Bible, the mistake led to the royal printers losing their license and a £300 fine.
4. Confusingly, the tribe that came to be known as the Flatheads was not one of them, as their heads were “flat,” like the white trappers’, while the neighboring tribes’ heads were bizarrely conical.
5. Grayscale reproduction scanned from Eaton, D.; Urbanek, S.: Paul Kane’s Great Nor-West, University of British Columbia Press; Vancouver, 1995.
6. In fact, Maryanne Fisher and her colleagues found the opposite; distress was greater if the infidelity involved someone with familial bonds (see Fisher, et al. [2009]).
7. Buss (2000), p. 33.
8. Buss (2000), p. 58.
9. Jethá and Falcato (1991).
10. Harris (2000), p. 1084.
11. For an overview of Buss’s research on jealousy, see Buss (2000). For research and commentary rebutting his work, see Ryan and Jethá (2005), Harris
and Christenfeld (1996), and DeSteno and Salovey (1996).
12. www.epjournal.net/filestore/ep06667675.pdf.
13. Holmberg (1969), p. 161.
14. From an “On Faith” blog post in The Washington Post, November 29, 2007: http://newsweek.washingtonpost.com/onfaith/panelists/richard_dawkins/2007/11/banishing_the_greeneyed_monste.html.
15. Wilson (1978), p. 142.
Part III: The Way We Weren’t
Chapter 11: “The Wealth of Nature” (Poor?)
1. Presumably, he was reading the sixth edition, published in 1826.
2. Barlow (1958), p. 120.
3. It’s no accident that Darwin was well aware of Malthus’s thinking. Harriet Martineau, an early feminist, economic philosopher, and out-spoken opponent of slavery, had been close to Malthus before striking up a friendship with Darwin’s older brother, Erasmus, who introduced her to Charles. Had Charles not been “astonished to find how ugly she is,” some, including Matt Ridley, suspect their friendship might have led to marriage. It would surely have been a marriage with lasting effects on Western thought (see Ridley’s article, “The Natural Order of Things,” in The Spectator, January 7, 2009).
4. Shaw (1987), p. 53.
5. Darwin (1871/2007), p. 79. Both Malthus and Darwin would have profited from familiarity with MacArthur and Wilson’s (1967) thoughts on r/K reproduction and selection. Briefly, they posit that some species (like many insects, rodents, etc.) reproduce quickly to fill an empty ecological niche. They don’t expect most of their young to survive to adulthood, but they flood the environment quickly (r-selected). K-selected species have fewer young and invest heavily in each of them. Such species are generally in a state of Malthusian equilibrium, having already reached a population/food supply stasis point. Thus, these questions: as Homo sapiens is clearly a K-selected species, at what point did our environmental niche become saturated? Or have we continually found ways to expand our niche as human population expanded? If so, what does this mean for the underlying mechanisms of natural selection when applied to human evolution?
6. For example: “In the roughly 2 million years our ancestors lived as hunters and gatherers, the population rose from about 10,000 protohumans to about 4 million modern humans. If, as we believe, the growth pattern during this era was fairly steady, then the population must have doubled about every quarter million years, on average.” Economics of the Singularity, Robin Hanson, http://www.spectrum.ieee.org/jun08/6274.
7. Source: U.S. Census Bureau: http://www.census.gov/ipc/www/ worldhis.html.
8. Lilla (2007).
9. Smith’s essay is online at http://realhumannature.com/?page_id=26.
10. Hassan (1980).
11. For a different take on how and why prehistoric population levels grew so slowly, see Harris (1977), particularly Chapter 2. For yet another take see Hart and Sussman (2005), who argue that our ancestors did in fact live in Hobbesian fear—but not from each other so much as from constant predation. Malthus acknowledged the low population growth of Native Americans, but he attributed it to lack of libido caused by food shortages, “phlegmatic temperament,” or “a natural defect in their bodily frame” (I. IV. P. 3).
12. Most of the other species of hominids that had spread from Africa to Asia and Europe previously were already long gone by the time modern humans wandered out of Africa. Those still hanging on, Neanderthals and (possibly) Homo erectus, would have been at a huge disadvantage if there was interspecies competition—which is unclear. One could argue that the presence of Neanderthals in Europe and parts of Central Asia may have led to competition over hunting areas, but the extent of contact between our ancestors and Neanderthals, if any, is unresolved. Also, any overlap would have been partial, as Neanderthals appear to have been top-level carnivores, while Homo sapiens are and were enthusiastic omnivores (see, for example, Richards and Trinkaus, 2009).
13. The question of when humans first arrived in the Americas is unresolved. Recent archaeological finds in Chile suggesting human settlements dating to about 35,000 years ago have thrown open the question of how and when the first humans arrived in the western hemisphere. See, for example, Dillehay et al. (2008).
14. See Amos and Hoffman (2009), for example. Paleoanthropologist John Hawkes isn’t convinced that population bottlenecks necessarily imply sparse prehistoric human populations overall, proposing that “many small groups of humans were in fact competing intensively, and many of them failed to persist over the long term. In other words, a small effective size is hardly evidence of no ancient competition or warfare. It may be the result of intense competition leading to many local extinctions” (see his blog: http://johnhawks.net/node/1894). Given the persistence of hunter-gather populations in the world’s least habitable zones, the
the genetic evidence of just a few hundred breeding pairs after the Toba eruption 70,000 years ago (Ambrose, 1998), we aren’t convinced by Hawkes’s scenario of “many local extinctions” due to competition— as opposed to planetary catastrophe.
15. Agriculture itself can be seen as a response to ecological saturation brought about by the combined effects of gradually rising regional population and catastrophic climate change. For example, Nick Brooks, a researcher at the University of East Anglia, argues, “Civilization was in large part an accidental by-product of unplanned adaptation to catastrophic climate change.” Brooks and others argue that the agricultural shift was a “last resort” response to deteriorating environmental conditions. For a comprehensive discussion of how climate change might have provoked agriculture, see Fagan (2004).
16. Known as “geophagy,” dirt eating is common in societies around the world—especially among pregnant and lactating women. Additionally, many otherwise toxic foods containing poisonous alkaloids and tannic acids are cooked along with alkaloid-binding clays. Clay can be a rich source of iron, copper, magnesium, and calcium—all critical during pregnancy.
17. August 5, 2007.
18. http://moneyfeatures.blogs.money.cnn.com/2009/04/30/millionaires-arent-sleeping-well-either/?section=money_topstories.
19. See Wolf et al.(1989) and Bruhn and Wolf (1979). Malcolm Gladwell (2008) also discusses Roseto.
20. Sahlins (1972), p. 37.
21. http://www.newyorker.com/online/blogs/books/2009/04/the-exchange-david-plotz.html.
22. Malthus (1798), Book I, Chapter IV, paragraph 38.
23. Darwin (1871/2007), p. 208.
24. For a more detailed analysis of how modern economic theory plays out (or doesn’t) among non-state societies, see Henrich et al. (2005) and Richard Lee’s chapter titled “Reflections on Primitive Communism,” in Ingold et al. (1988).
Chapter 12: The Selfish Meme (Nasty?)
1. In A Theory of Moral Sentiments, Smith wrote, “How selfish soever man may be supposed, there are evidently some principles in his nature, which interest him in the fortune of others, and render their happiness necessary to him, though he derives nothing from it, except the pleasure of seeing it.”
2. Gowdy (1998), p. xxiv.
3. From Mill (1874).
4. New York Times, July 23, 2002, “Why We’re So Nice: We’re Wired to Cooperate.” http://www.nytimes.com/2002/07/23/science/ why-we-re-so-nice-we-re-wired-to-cooperate.html. For the original research, see Rilling et al. (2002).
5. We’ve drawn from an excellent analysis of Hardin’s paper by Ian Angus, which can be found at http://links.org.au/node/595.
6. See Ostrom (2009), for example.
7. See Dunbar (1992 and 1993).
8. Harris (1989), pp. 344–345.
9. Bodley (2002), p. 54.
10. Harris (1989), p. 147.
11. van der Merwe (1992), p. 372. Also see Jared Diamond, “The Worst Mistake in the History of the Human Race” (widely available online; see here, for example: http://www.awok.org/worst-mistake/).
12. Le Jeune (1897), pp. 281–283.
13. Gowdy (1998), p. 130.
14. Quoted in Menzel and D’Aluisio, p. 178.
15. Harris (1977), p. x. Also see Eaton, Shostak, and Konner (1988).
16. Gowdy (1998), p. 13.
17. Gowdy (1998), p. 23.
18. Harris (1980), p. 81.
19. Ridley (1996), p. 249.
20. See de Waal (2009) for much more on the biological origins of empathy and instinctive justice.
21. Dawkins (1998), p. 212.
22. de Waal and Johanowicz (1993).
23. Sapolsky and Share (2004). Also see Natalie Angier, “No Time for Bullies: Baboons Retool Their Culture, New York Times, April 13, 2004.
24. Boehm (1999), p. 3, 68.
25. Fromm (1973), p. 60.
26. Gowdy (1998), p. xvii.
Relevant research published after Sex at Dawn.
1. Here’s a paper that supports our contention that egalitarian social organization is more functional for small scale social groups like those of the EEA (see references to Dunbar’s number) and that more hierarchical power structures emerge when the group gets too big for consensus rule.
A theory of leadership in human cooperative groups
Journal of Theoretical Biology
Available online 2 June 2010.
Paul L. Hooper Hillard S. Kaplan a and James L. Boone
Abstract
Two types of models aim to account the origins of rank differentiation and social hierarchy in human societies. Conflict models suggest that the formation of social hierarchies is synonymous with the establishment of relationships of coercive social dominance and exploitation. Voluntary or 'integrative' models, on the other hand, suggest that rank differentiation—the differentiation of leader from follower, ruler from ruled, or state from subject—may sometimes be preferred over more egalitarian social arrangements as a solution to the challenges of life in social groups, such as conflict over resources, coordination failures, and free-riding in cooperative relationships. Little formal theoretical work, however, has established whether and under what conditions individuals would indeed prefer the establishment of more hierarchical relationships over more egalitarian alternatives. This paper provides an evolutionary game theoretical model for the acceptance of leadership in cooperative groups. We propose that the effort of a leader can reduce the likelihood that cooperation fails due to free-riding or coordination errors, and that under some circumstances, individuals would prefer to cooperate in a group under the supervision of a leader who receives a share of the group's productivity than to work in an unsupervised group. We suggest, in particular, that this becomes an optimal solution for individual decision makers when the number of group members required for collective action exceeds the maximum group size at which leaderless cooperation is viable.
2. Here’s an article about a paper demonstrating hormonal differences in how male chimps and male bonobos respond to stress, with chimps gearing up for battle and bonobos chilling out. Quite interesting, in light of the never-ending debate about the relevance of these two primates to human nature:
http://www.telegraph.co.uk/science/science-news/7858951/What-kind-of-man-are-you-chimpanzee-or-bonobo.html
Chapter 13: The Never-Ending Battle over Prehistoric War (Brutish?)
1. From his closing argument in the Scopes case.
2. Wade (2006), p. 151.
3. Recent studies of mitochondrial DNA suggest that even before the human migrations out of Africa that began about 60,000 years ago, human populations were largely isolated from each other for as much as 100,000 years, localized in eastern and southern Africa. Only about 40,000 years ago did these two lines reunite, becoming a single pan-African population, according to this research. See Behar et al. (2008). Full paper available online at http://www.cell.com/AJHG/ fulltext/S0002-9297%2808%2900255-3#.
4. Readers interested in further exploration of the critique of Hobbesian assumptions regarding war in prehistory could begin with Fry (2009) and Ferguson (2000).
5. Pinker’s talk was based upon an argument he presents in The Blank Slate (2002), particularly in the last few pages of the third chapter.
6. The link to Pinker’s presentation is http://www.ted.com/index.php/talks/steven_pinker_on_the_myth_of_violence.html. You can find many other interesting presentations at this site. You might want to search Sue Savage-Rumbaugh’s talks on bonobos, for example. If you prefer to read Pinker’s remarks, an essay based upon the talk can be found at www.edge.org/3rd_culture/pinker07/pinker07_index.html.
7. Note that Pinker’s chart represents part of a chart in Keeley’s book (1996), and that Keeley refers to these societies as “primitive,” “prestate,” and “prehistoric” in his charts (pp. 89–90). Indeed, Keeley distinguishes what he calls “sedentary hunter-gatherers” from true “nomadic hunter-gatherers,” writing, “Low-density, nomadic hunter-gatherers, with their few (and portable) possessions, large territories, and few fixed resources or constructed facilities, had the option of fleeing conflict and raiding parties. At best, the only thing they would lose by such flight was their composure” (p. 31).
As we’ve established, these nomadic (immediate-return) hunter-gatherers are most representative of human prehistory—a period that is, by definition, before the advent of settled communities, cultivated food, domesticated animals, and so on. Keeley’s confusion (and thus, Pinker’s) is largely due to his referring to horticulturalists, with their gardens, domesticated animals, and settled villages, as “sedentary hunter-gatherers.” Yes, they do occasionally hunt and they sometimes gather, but because these activities are not their sole source of food, their lives are dissimilar to those of immediate-return hunter-gatherers. Their gardens, settled villages, and so on make territorial defense necessary and fleeing conflict much more problematic than it was for our ancestors. They—unlike true immediate-return foragers—have a lot to lose by simply fleeing aggression.
Keeley acknowledges this crucial difference, writing, “Farmers and sedentary hunter-gatherers had little alternative but to meet force with force or, after injury, to discourage further depredations by taking revenge” (p. 31).
The point bears repeating. If you live a settled life in a stable village, have a labor-expensive shelter, cultivated fields, domesticated animals, and too many possessions to carry easily, you’re not a hunter-gatherer. Prehistoric human beings did not have any of these things, which is, after all, precisely what made them “prehistoric.” Pinker either fails to appreciate this essential point, or simply ignores it.
8. Societies in Pinker’s chart:
—The Jivaro cultivate yams, peanuts, sweet manioc, maize, sweet potatoes, peanuts, tuber beans, pumpkins, plantains, tobacco, cotton, banana, sugarcane, taro, and yam. They also traditionally domesticate llamas and guinea pigs and later the introduced dog, chicken, and pig.
—The Yanomami are foraging, “slash-and-burn” horticulturists. They cultivate plantains, cassava, and bananas.
—The Mae Enga grow sweet potatoes, taro, bananas, sugarcane, Pandanus nuts, beans, and various leaf greens, as well as potatoes, maize, and peanuts. They raise pigs, used not only for meat but for important ritualistic celebrations.
—About 90 percent of the Dani diet is sweet potatoes. They also cultivate banana and cassava. Domestic pigs are important both for currency used in barter and for the celebration of important events. Pig theft is a major cause of conflict.
—The Murngin economy was based primarily on fishing, collecting shellfish, hunting, and gathering until the establishment of missions and the gradual introduction of market goods in the 1930s and 1940s. While hunting and gathering remain important for some groups, motor vehicles, aluminum boats with outboard engines, guns, and other introduced tools have replaced indigenous techniques.
—The Huli’s staple food is the sweet potato. Like other groups in Papua New Guinea, domestic pigs are prized for meat and status.
9. This, according to Fry (2009).
10. Knauft (1987 and 2009).
11. To make matters even worse, Pinker juxtaposes these bogus “hunter-gatherer” mortality rates with a tiny bar showing the relatively few war-related deaths of males in twentieth-century United States and Europe. This is misleading in many respects. Perhaps most important, the twentieth century gave birth to “total war” between nations, in which civilians (not just male combatants) were targeted for psycho- logical advantage (Dresden, Hiroshima, Nagasaki . . .), so counting only male mortalities is meaningless.
Furthermore, why did Pinker not include the tens of millions who died in some of the most vicious and deadly examples of twentieth-century warfare? In his discussion of “our most peaceful age,” he makes no mention of the Rape of Nanking, the entire Pacific theater of World War II (including the detonation of two nuclear bombs over Japan), the Khmer Rouge and Pol Pot’s killing fields in Cambodia, several consecutive decades-long wars in Vietnam (against the Japanese, French, and Americans), the Chinese revolution and civil war, the India/Pakistan separation and subsequent wars, or the Korean war. None of these many millions are included in his assessment of twentieth-century (male) war fatalities.
Nor does Pinker include Africa, with its never-ending conflicts, child soldiers, and casual genocides. No mention of Rwanda. Not a Tutsi or Hutu to be found. He leaves out every one of South America’s various twentieth-century wars and dictatorships infamous for torturing and disappearing tens of thousands of civilians. El Salvador? Nicaragua? More than 100,000 dead villagers in Guatemala? Nada. Absolutamente nada.
12. For example, see Zihlman et al. (1978 and 1984).
13. Why War?, available online at http://realhumannature.com/?page_id=26. After we contacted him to ask how he could possibly justify the omission, Smith at first cited Wrangham and Peterson’s dismissal of bonobos as being less representative than chimps of our last common ancestor. When we pointed out that many primatologists argue that bonobos are probably more representative), that even Wrangham had revised his opinion on the point, and in any case, it is factually wrong to say that chimps are our “closest non-human relative” without mentioning bonobos, he finally relented and added two brief references to bonobos to his lurid descriptions of chimps’ “bloody wars of attrition.” Since the online essay was an extract from his book, which was already in print, it seems unlikely these reluctant changes are reflected there.
14. Ghiglieri (1999), pp. 104–105.
15. For a review, see Sussman and Garber’s chapter in Chapman and Sussman (2004).
16. The quote is from de Waal (1998), p. 10.
17. Goodall (1971), cited in Power (1991), pp. 28–29.
18. Strangely,even though he agrees with this central point made by Power, de Waal barely mentions her work—and only to dismiss her, at that. In an endnote in his 1996 book, Good Natured: The Origins of Right and Wrong in Humans and Other Animals, he writes, “On the basis of her reading of the literature, Power (1991) has argued that provisioning at some field sites (such as Gombe’s banana camp) turned the chimpanzees more violent and less egalitarian, and thus changed the ‘tone’ of relationships both within and between communities. Power’s analysis—which blends a serious reexamination of available data with nostalgia for the 1960s image of apes as noble savages—raises questions that will no doubt be settled by ongoing research on unprovisioned wild chimpanzees.”
This dismissal of Power’s analysis strikes us as unjustified and uncharacteristically ungenerous. Regardless of whether or not she felt “nostalgia for the 1960s” (an emotion we didn’t detect in her book), de Waal admits her analysis “raises questions” that merit investigation. These questions threaten to recast a great deal of data concerning chimpanzee social interactions—of great interest to de Waal, one of the world’s leading authorities on chimpanzee behavior and a man whose scholarship demonstrates deep respect for critical analysis.
19. Ghiglieri (1999), p. 173.
20. For a review of these reports and a rebuttal to Power’s argument, see Wilson and Wrangham (2003). The paper is available online at http://anthro.annualreviews.org.
21. Nolan (2003).
22. Behar et al. (2008). Also, for an excellent review of this material, see Fagan (2004).
23. Turchin (2003 and 2006).
24. Readers with mental images of Sioux (Lakota) chiefs with eagle-feather war bonnets rippling in the wind should keep in mind that in the generations before first contact with whites, disease spread through many tribes and the arrival of horses brought severe cultural disruptions, leading to conflict between groups that had been at peace previously (see Brown, 1970/2001).
25. Edgerton (1992), pp. 90–104.
26. Ferguson (2003).
27. On Christmas Day, 1968, Apollo 8 astronaut Frank Borman read this prayer to a world audience: “Give us, O God, the vision which can see thy love in the world in spite of human failure. Give us the faith to trust the goodness in spite of our ignorance and weakness. Give us the knowledge that we may continue to pray with understanding hearts, and show us what each one of us can do to set forth the coming of the day of universal peace. Amen.”
28. Tierney (2000), p. 18. Tierney’s book sparked a conflagration that makes any chimpanzee community seem downright pacific in comparison. The bulk of the controversy concerns Tierney’s charges that Chagnon and his colleague, James Neel, may have caused a fatal epidemic among the Yanomami. Not having examined these charges in detail, we have nothing to add to that discussion, limiting our critique to Changnon’s methodology and scholarship as it applies to Yanomami warfare.
29. By comparison, Chagnon’s total time among the Yanomami adds up to about five years. Readers interested in knowing more about the Yanomani might start with Good (1991). This is a very personal and accessible account of his time living with them (and ultimately, taking a wife there). Tierney (2000) outlines the case against Chagnon, though going far beyond the critiques we’ve outlined here. Ferguson (1995) offers an in-depth analysis of Chagnon’s calculations and conclusions. For more of Ferguson’s views on the origins of war, the following two papers can be downloaded from his departmental web page (http://andromeda.rutgers.edu/socant/brian.htm): Tribal, “Ethnic,” and Global Wars, and Ten Points on War, which includes a broad discussion of biology, archaeology, and the Yanomami controversy. Borofsky (2005) offers a balanced account of the controversy and the context in which it occurred. Of course, Chagnon’s work is readily available as well.
30. Quoted in Tierney (2000), p. 32.
31. Washington Post review of Darkness in El Dorado: Jungle Fever, by Marshall Sahlins, Sunday, December 10, 2000, p. X01.
32. Chagnon (1968), p. 12.
33. Tierney (2000), p. 14.
34. Sponsel (1998), p. 104.
35. October 23, 2008.
Relevant research published after Sex at Dawn.
1. Quitting the hominid fight club: The evidence is flimsy for innate chimpanzee--let alone human--warfare
By John Horgan
http://www.scientificamerican.com/blog/post.cfm?id=quitting-the-hominid-fight-club-the-2010-06-29&posted=1#comments
Chapter 14: The Longevity Lie (Short?)
1. Note that these numbers are for demonstration purposes only. To keep it simple (and since it’s meaningless anyway), we haven’t adjusted for male/female size differences, regional variations in average infant skeleton sizes, and so on.
2. October 6, 2008.
3. Adovasio et al. (2007), p. 129.
4. Gina Kolata, “Could We Live Forever?,” November 11, 2003.
5. Scientific American, March 6, p. 57.
6. Harris (1989), pp. 211–212.
7. http://www.gendercide.org/case_infanticide.html.
8. These numbers don’t include the selective abortion of female fetuses, which is widespread in these countries. For example, Agence-France Presse
reports that selective abortions have left China with 32 million more men than women, and that in just one year (2005), more than 1.1 million more boys than girls were born in China.
9. Philosopher Peter Singer has written thought-provoking books and essays on the question of how to calculate the value of human versus nonhuman life. See, for example, Singer (1990).
10. Cited in Blurton Jones et al. (2002).
11. Blurton Jones et al. (2002).
12. See Blurton Jones et al. (2002).
13. An excellent paper highly recommended to readers interested in these matters is Kaplan et al. (2000). The paper can be downloaded at Kaplan’s faculty website: www.unm.edu/~hebs/pubs_kaplan.html.
14. From the paper by Kaplan et al. cited above, p. 171.
15. Readers interested in seeing how these same agricultural curses are playing out in the modern world might want to read Michael Pollan’s In Defense of Food: An Eater’s Manifesto (2009).
16. Larrick et al. (1979).
17. Source: Diamond (1997).
18. Edgerton (1992), p. 111.
19. Cohen et al. (2009).
20. Horne et al. (2008).
21. While we’re on the subject of hammocks, we’d like to take this opportunity to formally propose that hammocks—not spear points or stone blades—were the first example of human technology. That no hard evidence for this proposal has been unearthed is due to hammocks being made of perishable fibers. (Who wants a stone hammock?) Even chimps and bonobos fashion primitive hammocks by weaving together tree branches for sleeping platforms.
22. See Sapolsky (1998) for an excellent overview of how stress affects us. On the question of human/bonobo similarities concerning stress, it’s interesting to note that when bombs fell near them in World War II, all the bonobos in the zoo died from the stress the explosions caused, while none of the chimps perished (according to de Waal and Lanting, 1998).
23. The New Yorker, June 26, 2006, p. 76.
Part IV: Bodies in Motion
1. This quote is taken from a debate between Gould on one side and Steven Pinker and Daniel Dennett on the other. Well worth reading, if you like high-brow discussion with plenty of low blows, is “Evolution: The Pleasures of Pluralism,” The New York Review of Books 44(11): 47–52.
2. Potts (1992), p. 327.
Chapter 15: Little Big Man
1. Miller (2000), p. 169.
2. Though not always, as other factors can influence body-size dimorphism, apart from the intensity of male-male mating conflict. See Lawler (2009), for
example.
3. Male Australopithecus (between three and four million years ago) are thought to have been about fifty percent larger than females. Recent papers suggest Ardipethicus ramidus, another supposed human ancestor (thought to be a million or so years older than Australopithecus) was closer to our 15 to 20 percent levels. But keep in mind that the much-ballyhooed reconstruction of Ardipethicus ramidus relied upon bits and pieces of many different individuals, so our sense of body size dimorphism 4.4 million years ago is based upon educated guesses, at best (White et al., 2009).
4. Lovejoy (2009).
5. http://www.psychologytoday.com/articles/200706/ten-politically-incorrect-truths-about-human-nature.
6. Supplemental note. On sexual selection in relation to monkeys. Reprinted from Nature, November 2, 1876, p. 18. http://sacred-texts.com/aor/darwin/descent/dom25.htm.
7. As we’ll discuss in the next chapter, the genital echo theory posits that women developed pendulous breasts so that the cleavage would mimic the (is there a scientific term for this?) butt-crack that so enticed our primate ancestors. Following that line of reasoning, some argue that fancily named lipstick serves to re-create the bright red “hinder ends” that so perplexed poor Darwin.
8. See Baker and Bellis (1995) or Baker (1996) for the sperm-team theory.
9. Hrdy (1996) is a wonderfully erudite and engaging discussion of how some of Darwin’s personal sexual hang-ups are reflected still in evolutionary theory.
10. Supplemental note. On sexual selection in relation to monkeys. Reprinted from Nature, November 2, 1876, p. 18. http://sacred-texts.com/aor/darwin/descent/dom25.htm.
11. Diamond (1991), p. 62.
Chapter 16: The Truest Measure of a Man
1. de Waal (2005), p. 113.
2. In Barkow et al. (1992), p. 299.
3. Barash and Lipton (2001), p. 141.
4. Pochron and Wright (2002).
5. Wyckoff et al. (2000). Other research looking into primate testicular genetics has reinforced the impression that ancestral human mating behavior more closely resembled the promiscuity of chimps than the one-male-at-a-time gorillas. See, for example, Kingan et al. (2003), who conclude that although “predicting the expected intensity of sperm competition in ancestral Homo is controversial, . . . we find patterns of nucleotide variability at SgI in humans to resemble more closely the patterns seen in chimps than in gorillas.”
6. Short (1979).
7. Margulis and Sagan (1991), p. 51.
8. Lindholmer (1973).
9. For more on this, see work by Todd Shackelford, particularly Shackelford et al. (2007). Shackelford generously makes most of his published work available for free download at http://www.toddkshackelford .com/publications/index.html.
10. Symons (1979), p. 92. Although we probably disagree with half of his conclusions, and much of the science is out of date, Symons’s book is well worth reading for its wit and artistry alone.
11. Harris (1989), p. 261.
12. Sperm competition is an area of passionate debate. Space limitations (and quite possibly, readers’ interest) preclude us from a more thorough discussion—especially concerning the highly controversial claims of Baker and Bellis regarding sperm teams composed of specialized cells acting as “blockers,” “kamakaze,” and “egg-getters.” For a scientific review of their findings, see Baker and Bellis (1995). For a popularized review, see Baker (1996). For a balanced discussion of the controversy written by a third party, see Birkhead (2000), especially pp. 21–29.
13. Data primarily from Dixson (1998). 14. See, for example, Pound (2002). 15. Kilgallon and Simmons (2005). 16. Some readers will argue that these conventions in contemporary pornography are expressions of female subjugation and degradation rather than eroticism. Whether or not this is the case (a discussion we’re going to sidestep at this juncture), one must still ask why it is being expressed in this way, with these images, given that there are so many ways of visibly humiliating a person. Some authorities believe the practice of bukkake originated as a way of punishing adulterous women in Japan—a somewhat less Puritanical Scarlet Letter, if you will (see, for example, “Bake a Cake? Exposing the Sexual Practice of Bukkake,” poster presented at the 17th World Congress of Sexology, by Jeff Hudson and Nicholas Doong: http://abstracts.co.allenpress.com/ pweb/sexo2005/document/50214). If you don’t know what bukkake is, and you’re even slightly prone to being offended, please forget we even mentioned it.
Chapter 17: Sometimes a Penis Is Just a Penis
1. Frans de Waal suspects that bonobos have longer penises than humans, at least relative to body size, but most other primatologists seem to disagree with his assessment. In any case, there is no question that the human penis is far thicker than that of any other ape, in absolute terms or relative to body size, and far longer than that of any primate not clearly engaged in extreme sperm competition.
2. Sherfey (1972), p. 67.
3. One species of gibbon, the black-crested gibbon (Hylobates concolor), does in fact have an external, pendulous scrotum. Interestingly, this type of gibbon may also be exceptional in not being strictly monoga- mous (see Jiang et al., 1999).
4. Gallup (2009) offers an excellent summary of this material.
5. Dindyal (2004).
6. http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/7633400.stm2008/09/24.
7. Harvey and May (1989), p. 508.
8. Writing in the Encyclopedia of Human Evolution, Robert Martin notes, “Relative to body size, humans have a very low value for rmax—even in comparison with other primates. This suggests that selection has favoured a low breeding potential during human evolution. Any model of human evolution should take this into account.” A low rmax value along with the very high levels of sexual activity typical of humans is yet another indication that sex has long functioned for nonreproductive purposes in our species.
Similarly, while Dixson (1998) characterizes the seminal vesicles of monogamous and polygynous primates (except the gelada baboon) as vestigial or small, he classifies the human seminal vesicles as medium—noting that “it is reasonable to propose that natural selection might have favoured reduction in size of the vesicles under conditions where copulation is relatively infrequent and the need for large ejaculate volume and coagulum formation is reduced.” He goes on to propose that “this might explain the very small size of the vesicles in primarily monogamous [primates].”
9. BBC News online, July 16, 2003.
10. BBC News online, October 15, 2007.
11. Psychology Today, March/April 2001.
12. Barratt et al. (2009).
13. Hypothetically, one could try to falsify this hypothesis using data on testicular volume and sperm production from some of the societies we’ve discussed where sperm competition and partible paternity are in effect. To this end, we’ve contacted every anthropologist we could locate who has worked in the Amazon (or anywhere else with hunter-gatherers), but no one seems to have managed to gather these delicate data. Still, even if it were found that males in these societies showed higher testicular volume and sperm production, as our hypothesis predicts, definitive confirmation of the hypothesis would be precluded by the relative absence of the environmental toxins that are presumably at least partly responsible for testicular atrophy in industrialized societies.
14. BBC News online, December 8, 2006.
15. Diamond (1986).
16. W. A. Schonfeld, “Primary and Secondary Sexual Characteristics. Study of Their Development in Males from Birth through Maturity, with Biometric Study of Penis and Testes,” American Journal of Diseases in Children 65, 535–549 (cited in Short, 1979).
17. Harvey and May (1989). 18. Baker (1996), p. 316. 19. Bogucki (1999), p. 20.
Chapter 18: The Prehistory of O
1. Maines’s book has become an underground sensation. Written as a serious cultural history of the vibrator, the story she tells is surprising and compelling. As we write, a play based on the book written by Sarah Ruhl (In the Next Room) is playing on Broadway. A National Public Radio story on the play is here: http://www.npr.org/templates/ story/story.php?storyId=120463597&ps=cprs.
2. Quotes taken from Margolis (2004).
3. See Money (2000). Interestingly, semen depletion is central to the ancient Taoist understanding of male health and sexuality as well. See, for example, Reid (1989).
4. On Baker Brown, see Fleming (1960) and Moscucci (1996).
5. Coventry (2000).
6. Although the clitoris is often referred to as “the only organ in the human body whose sole function is to provide pleasure,” there are two problems with this observation. First, if female orgasm (pleasure) is functional in the senses we outline (increases chances of fertilization, inspires vocalizations, and thereby promotes sperm competition), then there is clearly a purpose to the pleasure. Secondly, what about male nipples? Not all men find them to be a site of pleasure, but they are certainly highly enervated and serve no functional purpose.
7. Margolis (2004), pp. 242–243.
8. Ironically, according to archaeologist Timothy Taylor (1996), this image of the Devil is thought to be derived from Cernunnos, the horned god, who was the Celtic translation of Indian tantric practice and thus originally a symbol of spiritual transcendence via sexual practice.
9. Coventry (2000).
10. Hrdy (1999b), p. 259.
11. Sherfey (1972), p. 113.
Chapter 19: When Girls Go Wild
1. Pinker (2002), p. 253.
2. Not to exclude women or gay men, but there is a dearth of scientific data on this particular angle. Interestingly, though, several people have reported to us anecdotally that when they’ve overheard their neighbors (both gay male and lesbian couples) having sex, the partner they considered to be the more feminine was the one who was making more noise.
3. When the director, Rob Reiner, showed the screenplay to his mother, she suggested that at the end of that scene, the camera cut to an older woman in the restaurant about to order, who says, “I’ll have what she’s having.” The line was so brilliant that Reiner told his mother he’d insert it, but only if she agreed to deliver the line in the film, which she did.
4. Semple (2001).
5. Small (1993), p. 142.
6. Small (1993), p. 170.
7. Dixson (1998), pp. 128–129.
8. Pradhan et al. (2006).
9. These quotes are from Hamilton and Arrowood (1978).
10. The intensity of the female’s vocalizations could, for example, guide the discerning male’s orgasmic response—thus increasing the chances of simultaneous or near-simultaneous orgasm. As we discuss below, there is evidence such timing could be to the male’s reproductive advantage.
11. The title, far from being the frat-boy declaration it may seem (“Without tits, there is no paradise.”), is the name of a Colombian television drama about young women who get breast implants hoping to attract the attentions of local drug lords and thereby escape poverty.
12. For example, Symons (1979) and Wright (1994).
13. See Morris (1967), Diamond (1991), and Fisher (1992).
14. http://dir.salon.com/story/mwt/style/2002/05/28/booty_call/.
15. Though they can be considered permanently swollen, this is not to say that breasts don’t change throughout a woman’s life (and menstrual) cycle. They typically swell further at pregnancy, menstruation, and orgasm (up to 25 percent greater than normal, according to Sherfey), and diminish in size and fullness with age and breastfeeding.
16. Small (1993), p. 128.
17. Haselton et al. (2007). Available online at www.sciencedirect.com.
18. Many accounts of human sexuality incorporate this explanation, but that of Desmond Morris is probably still the most widely known.
19. Dixson (1998), pp. 133–134.
20. Dixson refers specifically to macaques and chimps in this passage, though he’s speaking of the capacity for multiple orgasm in female primates in general in the section where the passage appears. Passages like this led us to wonder why Dixson hadn’t followed the data to where they seem to so clearly lead. We sent him an email outlining our argument and requesting his comments and criticisms, but if he received our message, he chose not to respond.
21. Symons (1979), p. 89.
22. Lloyd, a former student of Stephen Jay Gould, recently published an entire book in which she reviews (and rather contemptuously dismisses) the various adaptive arguments for the female orgasm (The Case of the Female Orgasm: Bias in the Science of Evolution). For a sense of why we don’t recommend her book, take a look at David Barash’s review, available online (“Let a Thousand Orgasms Bloom”). Download at http://www.epjournal.net/filestore/ep03347354.pdf.
23. As noted above, some of the findings of Baker and Bellis are highly controversial. We mention them because they are known to many in the general audience, but none of their findings are necessary to our argument.
24. Barratt et al. (2009). Available online at http://jbiol.com/content/8/7/63.
25. Pusey (2001).
26. Both quotes appear in Potts and Short (1999). The first quote is from the main text, page 38, and the second is quoting Laura Betzig, p. 39.
27. Dixson (1998), pp. 269–271. An excellent review of the development of the concept of postcopulatory sexual selection can be found in Birkhead (2000). Copious evidence for this filtering function can be found in Eberhard (1996), where the author presents dozens of examples of females exerting “post-copulatory control” over which sperm fertilize
their eggs.
28. Dixson (1998), p. 2.
29. Small (1993), p. 122.
30. Gallup et al. (2002).
Other Relevant Research
Nicholas A, Brody S, de Sutter P, and de Carufel F. A woman's history of vaginal orgasm is discernible from her walk. J Sex Med 2008;5:2119–2124.
Conclusions. The discerning observer may infer women's experience of vaginal orgasm from a gait that comprises fluidity, energy, sensuality, freedom, and absence of both flaccid and locked muscles. Results are discussed with regard to previous research on gait, the effect of the musculature on sexual function, the special nature of vaginal orgasm, and implications for sexual therapy.
Part V: Men Are from Africa, Women Are from Africa
1. Wright (1994), p. 58.
Chapter 20: On Mona Lisa’s Mind
1. Kendrick et al. (1998).
2. Baumeister (2000).
3. Chivers et al. (2007).
4. Much of the research reviewed here is mentioned in Bergner’s excellent article “What Do Women Want?—Discovering What Ignites Female Desire,”
January 22, 2009. Link: http://www.nytimes .com/2009/01/25/magazine/25desire-t.html.
5. Anokhin et al. (2006).
6. Georgiadis et al. (2006). Or, for a review: Mark Henderson, “Women Fall into a ‘Trance’ During Orgasm,” Times Online, June 20, 2005. http://www.timesonline.co.uk/tol/life_and_style/health/article535521.ece.
7. Tarin and Góomez-Piquer (2002).
8. Little’s quote is from BBC News article: http://news.bbc.co.uk/2/hi/health/2677697.stm.
9. Wedekind et al. (1995). A more recent follow-up that confirms these results is Santos et al. (2005).
10. Birth control pills don’t just interfere with women’s ability to sense MHC in men, but appear to affect other feedback systems as well. See Laeng and Falkenberg (2007), for example.
11. For a recent survey of this research, see Alvergne and Lummaa (2009).
12. This isn’t meant as an indictment of the pill. But in light of these changes, we’d strongly recommend that couples spend several months together using alternate forms of birth control before making long-term plans.
13. Lippa (2007). Available online at http://psych.fullerton.edu/rlippa/bbc_sexdrive.htm.
14. See Safron et al. (2007). A good review of related research is here: http://www.wired.com/medtech/health/news/2004/04/63115?currentPage=all. 15. Alexander and Fisher (2003).
Chapter 21: The Pervert’s Lament
1. Dixson (1998), p. 145.
2. Both these interviews appear on NPR’s This American Life, Episode #220. Available via free download at iTunes or at www.thislife.org.
3. According to Reid (1989), it was considered wise and healthful for young Chinese men to share their abundant sexual energies with older women, who would benefit from absorbing the energy released by male orgasm; likewise, it was felt that young women’s orgasms would infuse older men with increased vitality. The same pattern is found in some foraging societies, as well as among some South Pacific island cultures.
4. One example among many: Dabbs et al. (1991,1995) found, “Offenders high in testosterone committed more violent crimes, were judged more harshly by the parole board, and violated prison rules more often than those low in testosterone.”
5. Gibson (1989).
6. One wonders about the long-term social repercussions of widespread sexual frustration in adolescent males. To what extent, for example, is this frustration a contributing factor to the misogynistic rage many men experience? How does this frustration affect young men’s willingness to fight wars or join street gangs? While we don’t agree with arguments like those advanced by Kanazawa (2007) claiming that Islam sanctions polygyny in order to increase the male sexual frustration that creates a pool of available suicide bombers, it’s hard to dismiss the notion that intense frustration will often be expressed as misdirected rage.
7. Georgia has a serious problem with oral sex. Until 1998, it was illegal—even between a married couple in their own bedroom—and punishable by up to twenty years in prison.
8. For example, http://www.npr.org/templates/story/story.php?storyId= 102386952&ft=1&f=1001.
9. Fortenberry (2005).
10. All quotes from this section are taken from Prescott (1975).
11. See Elwin (1968) and Schlegel (1995).
12. “Some Thoughts on the Science of Onanism,” a speech delivered to the Stomach Club, a society of American writers and artists.
13. Money (1985).
14. See http://www.cirp.org/library/statistics/USA/.
15. Money (1985), pp. 101–102.
16. These men believed that any spices or strong flavors excited sexual energies, so they recommended bland diets to dampen the libido. Graham crackers and unsweetened breakfast cereal were originally marketed to parents of adolescent boys as foods that would help them evade the evils of masturbation. For a fictionalized—though largely accurate— depiction of these men and their movement, see Boyle (1993).
17. Interestingly, Freud’s nephew, Edward Bernays, is considered one of the founders of public relations and modern advertising. Among his many famous ad campaigns was the first to associate cigarettes with increased autonomy for women. In the 1920s, Bernays staged a legendary publicity stunt still taught in business classes today. He arranged to have fashion models march in New York’s Easter parade, each with a lit cigarette and wearing a banner calling it a “torch of liberty.” For more on this, see Ewen (1976/2001).
18. Farmers know that in order to get a bull to mate with the same cow more than a few times, the bull has to be tricked into thinking it’s a different cow. They do this by rubbing a blanket on another cow to absorb her scent and then throwing it on top of the cow to be mated. If the bull isn’t fooled into it, he’ll simply refuse—no matter how attractive the cow may be.
19. Sprague and Quadagno (1989).
20. See, for example, the documentary film “Rent a Rasta,” written and directed by J. Michael Seyfert: www.rentarasta.com, or the feature film “Heading South,” directed by Laurent Cantet,
21. The New Yorker, July 6 and 13, 2009, p. 68.
22. Additionally, the so-called Westermark effect appears to strongly dissuade sex between close familiars.
23. See, for example, Gray et al. (1997 and 2002) and Ellison et al. (2009).
24. See, for example, Glass and Wright (1985).
25. Roney et al. (2009), but also see Roney et al. (2003, 2006, and 2007).
26. Davenport (1965).
27. Kinsey et al. (1948), p. 589.
28. Symons (1979), p. 232.
29. Bernard (1972/1982).
30. Berkowitz and Yager-Berkowitz (2008).
31. Symons (1979), p. 250.
32. See, for example, Roney et al. (2003). Regular aerobic exercise, lots of garlic, stress avoidance, and plenty of sleep are also good ways to “keep it up.” We should note that despite the anecdotal evidence, few scientists have risked ridicule by applying for grants to study the hormonal changes in philanderers. The phenomenon is well documented in other mammals, however (see, for example, Macrides et al., 1975). It’s possible the effect may be mediated not by actual intercourse so much as by pheromones, which might explain the bulusela shops where Japanese men purchase girls’ vaccum-packed (but used) panties from vending machines. Enterprising graduate students might want to consider research similar to Wedekind’s “Sweaty T-shirt study,” but with women’s panties instead of men’s shirts in the plastic bags, to see whether exposure to novel women’s genital pheromones alone is enough to affect testosterone blood concentrations in men.
33. For example, for depression: Shores et al. (2004); heart disease: Malkin et al. (2003); dementia: Henderson and Hogervorst (2004); mortality: Shores et al. (2006).
34. Squire quoted by Phillip Weiss in his provocative article in New York magazine: “The affairs of men: The trouble with sex and marriage.” May 18, 2008. Available here: http://nymag.com/relationships/sex/47055.
Chapter 22: Confronting the Sky Together
1. Wilson (1978), p. 148.
2. Holmberg (1969), p. 258.
3. “Is There Hope for the American Marriage?” Caitlin Flanagan Time, July 2, 2009. http://www.time.com/time/nation/article/0,8599,1908243,00 .html.
4. These quotes from Druckerman were taken from a review of her book in The Observer, July 8, 2007.
5. Jaynes (1990), p. 67.
6. “What does marriage mean?” Dan Savage. In Salon.com, July17, 2004: http://www.salon.com/mwt/feature/2004/07/17/gay_marriage/index.html.
7. Squire quoted by Weiss in New York magazine: “The affairs of men: The trouble with sex and marriage.” May 18, 2008. Available here: http://
nymag.com/relationships/sex/47055.
8. “Only You. And You. And You. Polyamory—relationships with multiple, mutually consenting partners—has a coming-out party.” By Jessica Bennett. Newsweek (Web Exclusive) July 29, 2009. http://www .newsweek.com/id/209164.
9. Hrdy (2001), p. 91.
10. “Scenes from a group marriage.” By Laird Harrison. Salon.com. http://mobile.salon.com/mwt/feature/2008/06/04/open_marriage/index.html.
11. http://andrewsullivan.theatlantic.com/the_daily_dish/2009/01/ted-haggard-a-1.html.
12. McElvaine (2001), p. 339.
13. Perel (2006), p. 192.
14. Gould (2000), pp. 29–31.
15. After all, in the 1970s, somebody bought nearly four million copies of Open Marriage, by Nena and George O’Neill.
16. Perel (2006), pp. 192–194.
17. Burnham and Phelan (2000), p. 195.
18. Perel (2006), p. 197.
19. Bergstrand and Blevins Williams (2000).
20. Easton and Liszt (1997).
21. You can hear the press conference at www.thisamericanlife.org/Radio_Episode.aspx?episode=95.
22. We first learned of this striking sun/moon relation in Weil (1980), a fascinating book on the consciousness-altering potential of everything from solar eclipses to perfectly ripe mangoes.