We hope this quick survey of remaining theoretical puzzles in evolutionary psychology makes it abundantly clear that there are still many questions to be asked and many puzzles to be solved in modern evolutionary psychology. We both left sociology and became evolutionary psychologists in response to one sentence by Robert Wright in his 1994 book The Moral Animal: “For now, this is the state of evolutionary psychology: so much fertile terrain, so few farmers.”23 We became farmers and started tilling the fertile terrain. Wright’s observation for evolutionary psychology is much less true now in 2007 than it was in 1994, as a large number of young and talented graduate students in psychology, anthropology, and elsewhere choose to pursue evolutionary psychology, which is probably the fastest growing academic field today.
At the 17th Annual Conference of the Human Behavior and Evolution Society (the main academic organization of evolutionary psychologists) held in Berlin in 2004, the then HBES president Bobbi S. Low remarked that the number of people who were on the program committee, which successfully planned and organized the Berlin conference in 2004, was larger than the entire group of people who originally gathered only two decades earlier to form the academic organization that later became HBES. Many attendees of these early meetings slept on the floor of Low’s house when they met at the University of Michigan in the 1980s.24 Twenty years later, the 2005 HBES meetings were held in the Hyatt Regency in Austin, Texas, with nearly five hundred participants. We have a feeling that five hundred house guests would have stretched even Low’s enormous hospitality.
The growth of evolutionary psychology has also been international; in addition to the United States and the United Kingdom, where scientific research in every field is most active, evolutionary psychology has a particularly and disproportionately large following in Japan and Belgium. Yet we could always use more bright minds to help us solve the remaining theoretical puzzles in evolutionary psychology. Apply within.
Notes
Preface
1Miller and Kanazawa (2000).
Introduction
1Maynard Smith (1997).
2Ridley (1999, pp. 54–64).
3Pinker (2002).
4Scarr (1995).
[5]Wilson (2007) is a late exception.
6Moore (1903).
7Hume (1739).
8Davis (1978).
9Ridley (1996, pp. 256–8).
10Alexander et al. (1979); Kanazawa and Novak (2005).
11Calden, Lundy, and Schlafer (1959); Gillis and Avis (1980); Sheppard and Strathman (1989).
12Davis et al. (1993); Rand and Kuldau 1990).
Chapter 1
1Buss (1989); Daly and Wilson (1988).
2Barkow, Cosmides, and Tooby (1992).
3Ellis and Bjorklund (2005, p. x).
4Barkow (2006); Tooby and Cosmides (1992, pp. 24–49).
5Ellis (1996); Daly and Wilson (1988, pp. 152–6).
6Campbell (1999, p. 243).
7Pinker (2002).
8Ellis (1996).
9Cornwell, Palmer, and Davis (2000); Cornwell et al. (2001); Machalek and Martin (2004).
[10]In this section we present a brief introduction to the field of evolutionary psychology. Nonacademic readers who would like a more extensive introduction may consult David M. Buss’s The Evolution of Desire: Strategies of Human Mating (Buss 1994), Matt Ridley’s The Red Queen: Sex and the Evolution of Human Nature (Ridley 1993), and Robert Wright’s The Moral Animal: The New Science of Evolutionary Psychology (Wright 1994). Academic readers might want to consult Barkow, Cosmides, and Tooby (1992); Buss (1995, 1999); Cartwright (2000); Daly and Wilson (1988); and Kanazawa (2001a).
[11]We must define natural and sexual selection explicitly, because our usage may appear a bit unorthodox to anyone with some background in evolutionary biology. We define natural selection as the process whereby some individuals live longer than others, and sexual selection as the process whereby some individuals leave more offspring (or copies of their genes) than others. Natural selection is a matter of survival; sexual selection is a matter of reproductive success. This is how Darwin originally defined natural and sexual selection—as two separate processes. That is why he wrote two separate books—On the Origin of Species by Means of Natural Selection (1859) to explain natural selection, and The Descent of Man, and Selection in Relation to Sex (1871) to explain sexual selection. In the 1930s, however, biologists redefined natural selection to subsume sexual selection and began to contend that differential reproductive success was the currency of natural selection. This is now the orthodoxy in all biological textbooks, which claims that sexual selection is but one branch of natural selection (Cronin 1991, pp. 231–43).
In this book, we argue against this orthodoxy. We concur with Geoffrey F. Miller (2000, pp. 8–12), Anne Campbell (2002, pp. 34–5), and others in the current generation of evolutionary psychologists and believe that we should return to Darwin’s original definitions and treat natural and sexual selection as two distinct processes. This is still controversial and of the minority, but we firmly believe that the conceptual separation of natural and sexual selection will bring clarity in evolutionary biology and psychology.
12Williams (1966).
13Barash (1982, pp. 144–7).
14Daly, Wilson, and Weghorst (1982).
15Gaulin, McBurney, and Brakeman-Wartell (1997).
16Cerda-Flores et al. (1999).
17Baker and Bellis (1995, p. Conclusion, box 8.4).
18Buss (1988, 2000); Buss and Shackelford (1997).
19White (1981); Buunk and Hupka (1987).
20Buss, Larsen, and Westen (1992); Buss et al. (1999).
21Harris (2003); DeSteno et al. (2002).
[22]Pietrzak et al. (2002). As one of the deans of modern evolutionary psychology, David M. Buss, points out (Buss, Larsen, and Western 1996), evolutionary psychologists (Daly, Wilson, and Weghorst 1982; Symons 1979, pp. 226–46) predicted the existence of these sex differences in romantic jealousy on the basis of evolutionary logic alone more than a decade before any systematic data existed.
23Betzig (1997a).
24van den Berghe (1990, p. 428).
25Endorsement on the cover of Betzig (1997b).
26Bowlby (1969).
27Kanazawa (2002, 2004b).
28Kanazawa (2002).
29Buss (1988).
30Crawford (1993); Symons (1990); Tooby and Cosmides (1990).
31Kanazawa (2004a).
Chapter 2
1Blum (1997); Mealy (2000); Moir and Jessel (1989); Pinker (2002, pp. 337–71).
2Connellan et al. (2000).
3Alexander and Hines (2002).
4Brown (1991); Pinker (2002, appendix, pp. 435–9).
5Alexander et al. (1979); Daly and Wilson (1988, pp. 140–2).
[6]Actually, as we argue in chapter 4, all human societies at all times are polygynous. They practice either simultaneous polygyny, allowing some men to have multiple wives simultaneously, as happens in Muslim and African tribal societies; or serial polygyny, allowing some men to have multiple wives sequentially through divorce and remarriage. The only truly and strictly monogamous societies prohibit simultaneous polygyny, divorce and remarriage, or extramarital affairs. No human societies known to anthropologists belong to this category (Betzig 1989) and thus more men than women always remain mateless in every society, given a roughly 50–50 sex ratio.
[7]The figure most often cited for the total number of children sired by Moulay Ismail the Bloodthirsty, taken from the 1976 edition of the Guinness Book of World Records (McWhirter and McWhirter 1975), is 888. However, according to the 1995 edition of the same book (Young 1994, p. Chapter 1), it is at least 1,042.
8Betzig (1986).
9Campbell (1999, 2002).
10Clutton-Brock and Vincent (1991).
11Trivers (1972).
12Harris (1974).
13Chomsky (1957).
14Pinker (1994).
15van den Berghe (1990, p. 428).
16Freeman (198
3, 1999).
17Chagnon (1968).
18Nance (1975).
19Hemley (2003).
20Ridley (1996, pp. 213–5).
Chapter 3
1Buss (1989).
2Bloch (1994, pp. 1–13).
3Abdollahi and Mann (2001).
4Crawford, Salter, and Jang (1989).
5Kanazawa and Still (2000b).
6Etcoff (1999, pp. 89–129); Mesko and Bereczkei (2004).
7Etcoff (1999, pp. 122–6).
8Singh (1993); Singh and Young (1995); Singh and Luis (1995).
9Jasienska et al. (2004).
10Symons (1995, p. Chapter 4).
11Cartwright (2000, pp. 153–4).
12Marlowe (1998).
13Jasienska et al. (2004).
14Rich and Cash (1993).
15Bloch (1994, pp. 1–13).
16Wall (1961).
17Ramanchandran (1997).
18Feinman and Gill (1978).
19van den Berghe and Frost (1986).
20Wong and Ellis (1984).
21Feinman and Gill (1978).
22Ridley (1993, pp. 293–5).
23Feinman and Gill (1978).
24Kenrick and Keefe (1992).
25Hess (1975); Hess and Polt (1960).
26Feinman and Gill (1978, p. Chapter 2, table 1).
27Cunningham, Druen, and Barbee (1997).
28Wagatsuma and Kleinke (1979).
29Bernstein, Tsai-Ding, and McClellan (1982); Cross and Cross (1971).
30Cunningham et al. (1995).
31Jones (1996); Jones and Hill (1993).
32Maret and Harling (1985).
33Morse and Gruzen (1976).
34Thakerar and Iwawaki (1979).
35Langlois et al. (1987); Samuels and Ewy (1985).
36Slater et al. (1998).
37Langlois, Roggman, and Rieser-Danner (1990).
38Symons (1995).
39Little et al. (2002).
40Gangestad, Thornhill, and Yeo (1994); Mealey, Bridgstock, and Townsend (1999); Perrett et al. (1999).
41Bailit et al. (1970); Møller (1990, 1992); Parsons (1992).
42Parsons (1990).
43Gangestad and Buss (1993).
44Langlois and Roggman (1990); Rubenstein, Langlois, and Roggman (2002).
45Langlois and Roggman (1990).
46Thornhill and Gangestad (1993).
47Thornhill and Møller (1997, pp. 528–33).
48Langlois et al. (2000); Shackelford and Larsen (1999).
49Hönekopp, Bartholomé, and Jansen (2004).
50Henderson and Anglin (2003).
51Al-Eisa, Egan, and Wassersub (2004).
52Kalick et al. (1998).
53Grammer and Thornhill (1994).
54Langlois et al. (1994).
55Trivers (1972).
56Pérusse (1993, pp. 273–4).
57Pérusse (1993, p. 273).
58Buss and Schmitt (1993).
59Ellis and Symons (1990).
60Buss and Schmitt (1993).
61Salmon and Symons (2001, 2004).
62Symons (1979, pp. 170–84).
63Ellis and Symons (1990).
64Buss and Schmitt (1993).
65Hejl, Kammer, and Uhl (Forthcoming).
66Carroll (1999); Gottschall et al. (2004); Thiessen and Umezawa (1998); Wilson (1998, pp. 210–37).
67Buss (1989).
68Kenrick and Keefe (1992).
69Kenrick and Keefe (1992).
70Abbey (1982).
71Kanazawa (2006a); Liedtke (2000); Pate (2001); Ream (2000).
72Haselton (2003); Haselton and Buss (2000).
73Yamagishi, Jin, and Kiyonari (1999).
[74]If you are familiar with elementary statistics, you recognize the false-positive and false-negative errors as “Type I” and “Type II” errors.
75Haselton and Buss (2000, p. Chapter 4); Haselton and Nettle (2006).
76Yamagishi et al. (Forthcoming).
77Guthrie (1993).
78Boyer (2001).
Chapter 4
1Emlen (1995).
2Smith (1984, p. 604, figure 1A).
3Smith (1984, p. 609).
4Cerda-Flores et al. (1999); Gaulin, McBurney, and Brakeman-Wartell (1997).
5White (1988).
6Chisholm and Burbank (1991).
7Bellis and Baker (1990); Birkhead and Møller (1991).
8Cartwright (2000, p. References, table 8.1).
9Gallup et al. (2003, p. 278).
10Gallup et al. (2003, p. 278).
11Gallup et al. (2003).
12Baker and Bellis (1995).
13Barash and Lipton (2001).
14Alexander et al. (1979); Leutenegger and Kelly (1977).
15Alexander et al. (1979, pp. 428–30, table 15-3).
16Mealey (2000, p. 306).
17Alexander et al. (1979); Leutenegger and Kelly (1977).
18Kanazawa and Novak (2005).
19Silventoinen et al. (2001).
20Biro et al. (2001); Frisch and Revelle (1970); Helm, Münster, and Schmidt (1995); Jaruratanasirikul, Mo-suwan, and Lebel (1997); Nettle (2002); Okasha et al. (2001).
[21]There is a third, even newer explanation of the evolution of sexual dimorphism in size (Kanazawa 2005a), although not of the relationship between polygyny and sexual dimorphism. The application of the generalized Trivers-Willard hypothesis (see “Boy or Girl? What Influences the Sex of Your Child?” in chapter 5) suggests that tall and heavy parents (both mothers and fathers) are more likely to have sons, and short and light parents are more likely to have daughters, because large body size is more adaptive for men than for women. Available empirical evidence supports this prediction of the generalized Trivers-Willard hypothesis. Body size(height and weight) are substantially heritable. Sexual dimorphism in size may therefore have evolved through this mechanism in addition to the effect of polygyny on the age of puberty.
22Kirkpatrick (1987); Small (1993); Trivers (1972).
23Kanazawa and Still (1999).
24Shaw (1957, p. 254).
25Dawkins (1986).
[26]Davies (1989); Orians (1969); Searcy and Yasukawa (1989); Verner (1964); Verner and Willson (1966). Borgerhoff Mulder (1990) is an earlier application of the polygyny threshold model to human society.
27Lenski (1966, pp. 308–18).
28Kanazawa and Still (2001).
29Betzig (1986).
30Kanazawa (2003a); Pérusse (1993, 1994).
31Kanazawa and Still (1999).
32Katzev, Warner, and Acock (1994); Morgan, Lye, and Condran (1988).
33Draper and Harpending (1982).
34Thornhill (1976).
35Sozou and Seymour (2005).
36Gangestad and Simpson (2000).
37Draper and Harpending (1982).
38Trivers (1972).
39Gangestad and Thornhill (1997).
40Rhodes, Simmons, and Peters (2005).
41Gangestad and Simpson (2000, p. 583).
Chapter 5
1Daly and Wilson (1985).
2Daly and Wilson (1999).
3Trivers and Willard (1973).
4Betzig (1986).
5Betzig and Weber (1995).
6Cronk (1989).
7Voland (1984).
8Moore (1990, pp. 326–7, figures 1–2).
9Mueller (1993).
10Kanazawa (2006c).
11Ellis and Bonin (2002); Freese and Powell (1999); Keller, Nesse, and Hofferth (2001).
12Cronk (1991); Gaulin and Robbins (1991); Kanazawa (2001d); Trivers (2002, pp. 120–2).
13Kanazawa (2005a, 2006b, 2007); Kanazawa and Vandermassen (2005).
14Baron-Cohen (1999, 2002, 2003); Baron-Cohen and Hammer (1997); Baron-Cohen, Lutchmaya, and Knickmeyer (2004).
15Kanazawa and Vandermassen (2005).
[16]The regression equations in Kanazawa and Vandermassen (2005, p. 595, table 1) include control variables for the respondent’s education and income (to control for the effect of parental socia
l class predicted in the original Trivers-Willard hypothesis), as well as age, age at first marriage, race, and current marital status. Then, controlling for the number of children of the opposite sex, having a systemizing occupation increases the number of sons by 0.3498 ( p < 0.01), and having an empathizing occupation increases the number of daughters by 0.3981 ( p < 0.01).
Let SO = the mean number of sons among the general population, DO = the mean number of daughters among the general population, SE =the mean number of sons among engineers and other systemizers, and DN =the mean number of daughters among nurses and other empathizers.
For our computation of SE, assume DO = DE = 1. Then, SO = 1.0500, and SE = 1.0500 +.3498 = 1.3998. For our computation of DN, assume SO = SE = 1. Then, DO = 0.9524, and DN = 0.9524 + 0.3981 = 1.3505. We thank Jouni Kuha for help with these computations.
17Kanazawa (2005a).
18Chagnon (1997).
19de Waal (1982).
20Kanazawa (2006b).
21Kanazawa (2007).
22Kanazawa (2007); Takahashi et al. (2006).
23Christenfeld and Hill (1995).
24McLain et al. (2000).
25Brédart and French (1999); Bressan and Grassi (2004).
26Daly and Wilson (1982); McLain et al. (2000); Regalski and Gaulin (1993).
27McLain et al. (2000).
28Kanazawa and Still (2000a, p. Chapter 1, appendix).
29Liss (1987, p. 781).
30US Bureau of the Census (1995, p. Introduction, table B).
31Bellis et al. (2005).
32Kanazawa and Still (2000a).
33Daly and Wilson (1988, pp. 62–3).
34Campbell (1988); Fischer and Oliker (1983); Marsden (1987).
35Smith-Lovin and McPherson (1993); Munch, McPherson, and Smith-Lovin (1997).
36Smith-Lovin and McPherson (1993, pp. 234–5).
37Kanazawa (2001b).
38Draper and Harpending (1982, 1988); Ellis et al. (1999).
39Ellis et al. (2003); Quinlan (2003).
40Ellis (2004, pp. 922–4).
41Kaprio et al. (1995); Rowe (2002).
42Ellis (2004).
43Draper and Harpending (1982, 1988).
44Quinlan (2003).
45Bailey et al. (2000); Kanazawa (2001c).
46Kanazawa (2001c).
47Herman-Giddens et al. (1997); Lemonick (2000).
48Ellis (2002).
Chapter 6
1Daly and Wilson (1988).
2Brown (1991).
3Pinker (2002, pp. 435–9, appendix).
4Kanazawa (2006c).
5International Criminal Police Organization (various years).
Why Beautiful People Have More Daughters: From Dating, Shopping, and Praying to Going to War and Becoming a Billionaire–Two Evolutionary Psychologists Explain Why We Do What We Do Page 19