5. WILL THE REAL PLEISTOCENE FAMILY PLEASE STEP FORWARD?
1. For an evocative account of the era, see Hewlett and West 1998. For historical overview, see Coontz 1992, 2005.
2. Popenoe 1996:191; see also Blankenthorn 1995:220.
3. Popenoe 1996:175; Sylvia Hewlett and Cornel West 1998:159–160 echo the same point when they write that paternal certainty “is the most important precondition for paternal investment”; cf. Symons 1979; Gaulin and Schlegel 1980.
4. For important exceptions see Werner 1984; Werner and Smith 1992; Rutter 1974; Rutter and O’Connor 1999; Ahnert 2005.
5. Quotations from La Barre’s The Human Animal (1967:104). See also the prominently published overview on the “origin of man” published in Science (Lovejoy 1981).
6. Popenoe 1996; Blankenthorn 1995. See also Commission on Children at Risk 2003.
7. On the family, see Moynihan 1986; Graglia 1998; Westman 2001.
8. For quotation, see Carey 2005. For more about “Marriage Protection Week” and former President Bush’s proclamation in support of the family see www.whitehouse.gov/news/release/2003/10/20031003-12.html. These views continue to be widely expressed, as by the founder of Focus on the Family, James Dobson, who told an audience that years of social research “indicates that children do best co-raised by their married mother and father” (quoted in Seelye 2007).
9. “California girl with lesbian parents expelled,” New York Times, Sept. 24, 2005.
10. The case was Lofton v. Secretary of Florida Department of Children and Families, No. 04-478 (Greenhouse 2005).
11. Lancaster and Lancaster 1987; Lee and Kramer 2002 and references therein.
12. For history and critical overview of the hunting hypothesis see O’Connell et al. 2002; Hawkes 2004b.
13. Quotation from Lovejoy 1981:341. Lovejoy was in turn building on classic papers by Washburn and Hamburg 1968. For critical overview see Hawkes 2004b.
14. Quotation from Lovejoy 1981:341. Updated versions of this hypothesis can still be found in the best textbooks evolutionary anthropology has to offer, for example, Boyd and Silk 1997:435.
15. Lee 1979; Hewlett 1991b.
16. Lawrence and Nohria 2002; see p. 182 for quotation about “true family values.”
17. Tyre and McGinn 2003.
18. Buss 1994a; Pinker 1997. My own opinion is that the pursuit of wealthy men has more to do with more recent history—post-Pleistocene social and economic transformations that gave men in patriarchal societies control over the resources women need to reproduce (Hrdy 1999, 2000).
19. See letters in response to Lovejoy 1981 published in subsequent issues by Cann and Wilson 1982, and others; Hrdy and Bennett 1979; Hawkes, O’Connell, and Blurton Jones 2001; Hawkes 2004b.
20. O’Connell et al. 2002:862 and throughout.
21. O’Connell et al. 2002:838.
22. Regarding the 96 percent failure rate, see Hawkes, O’Connell, and Blurton Jones 2001.
23. See Bliege Bird’s (2007) lovely case study on women’s preferences for “reliable fish” over “big fish” among the Meriam of Australia’s Torres Straits.
24. Bruce and Lloyd 1997. For more on the political and ecological pressures contributing to increasing numbers of single-parent households, see Lancaster 1989.
25. Engle and Breaux 1998.
26. Data from 2001, in Dominus 2005. See also Engle and Breaux 1998 for South America; Associated Press 1994.
27. For a rich and impressive literature on this subject, begin with Bruce, Lloyd, et al. 1995; Engle 1995; Engle and Breaux 1998; Ramalingaswami, Jonsson, and Rodhe 1996.
28. Marlowe 2005b.
29. Chagnon 1992:177 for the Yanomamo; Hewlett 1991a for the Aka, 1991b for preindustrial societies.
30. In their 2008 overview of 45 mostly natural fertility, natural mortality populations, Sear and Mace calculate that the presence of fathers had no impact on the survival of young children (usually under age five) in 53 percent of them. This estimate rose to 68 percent when they included data from supplementary societies for which information was less complete. Given how variable paternal impact is, and how much depends on who else is around and willing to help, these percentages should be cited with caution and caveats. See Chapter 8 for further discussion.
31. Johnson and Earle 2000:170.
32. Hill and Hurtado 1996; Marlowe 2001, 2005b; Wood 2006.
33. Hill and Kaplan 1988; Hill and Hurtado 1996:375ff. The minimal role alloparents play in infant care among the Ache may be a factor.
34. See Daly and Wilson 1984, 1999 for overviews; Hill and Hurtado 1996:375ff for Ache case.
35. The 87 percent figure derives from the period when the Ache still lived full-time as forest nomads (Hill and Kaplan 1988, Part I; Hill and Hurtado 1996:424 and Table 13.1).
36. Hill 2002:112.
37. Hawkes’s ideas were developed in the course of fieldwork with the Ache as well as the Hadza (Hawkes 1991).
38. Marlowe 2001.
39. See Otterbein 1968 for the Marquesan Islanders in the Pacific; Hakansson 1988 for densely populated areas of Kenya; Sangree 1980 and Guyer 1994, esp. pp. 231–232, for other African cases; Leacock 1980 for Montagnais-Naskapi; Kjellström 1973 for Eskimos; Goodale 1971 for Tiwi of Australia; Sommer 2005 for Qing China; Prince Peter 1963 and Hua 2001 for people of Tibetan origin; and many others reviewed in Hrdy 2000 and in Beckerman and Valentine 2002, esp. the volume’s introduction.
40. Briefly summarized in Hrdy 2000. In addition to references there, see Sommer 2005 for very poor in Qing Dynasty China; Freeman 1979:99–100, 131–132 for Indian “untouchables.”
41. For case studies see McAdoo 1986 for the United States; Brown 1973 for the Dominican Republic; Stack 1974 for the American South; Bolles 1986 for urban Jamaica; and esp. Borgerhoff Mulder 2009 for the contemporary Tanzanian Pimbe.
42. Lancaster 1989; Hrdy 1999, ch. 10.
43. Carneiro n.d.; Crocker and Crocker 1994; anthology compiled by Beckerman and Valentine (2002). For descriptions of the less bellicose, “gentler,” and less polygynous Yanomamo living in highland areas on the periphery of the Yanomamo heartland, see Chagnon 1992:101–111, writing about fieldwork he did late in his career, after 1991.
44. For early report on Yanomamo polyandry see Peters and Hunt 1975; Peters 1982.
45. In the human case, romantic feelings as well as sexual jealousy may also be involved, e.g., Shostak 1976; Jankowiak 1995; Leckman et al. 2005.
46. Beckerman et al. 1998; Hill and Hurtado 1996.
47. For the Canela see Crocker and Crocker 1994. For the Kulina, Pollock 2002. For matrilineal vs. patrilineal interests, see Hrdy 1999, ch. 10.
48. Pollock 2002:53. For more on “the optimal number of fathers” see Hrdy 2000.
49. Pollock 2002:54.
50. Haig 1999. According to Ely et al. 2006, a few chimpanzee twin sets are born with different fathers. Twinning in humans, and presumably chimerism as well, may increase under certain ecological conditions (e.g., Hrdy 1999:202–203), but nothing like the frequency of chimeras found in marmosets ever occurs in humans.
51. “Who’s your daddy?” Med Headlines, March 9, 2008 (www.medheadlines.com).
52. Leacock 1980:31.
53. The full quotation reads, “Our early semi-human ancestors would not have practiced infanticide or polyandry. For the instincts of the lower animals are never so perverted as to lead them to regularly destroy their own offspring or to be quite devoid of jealousy” (Darwin 1974:45); this view that polyandrous mating by women could not be other than exceedingly rare because otherwise men would never invest was an early tenet of evolutionary psychology (e.g., Symons 1982) and persists today (e.g., Pinker 1997).
54. Regarding motivation and hunting as “parental effort,” see Marlowe 1999b. For meat allocations, see Marlowe 2005b. Data were for children eight years old or younger.
55. Smuts 1985; Palombit 1999, 2001; Palombit et al. 2001; and esp. Alberts 1999.
56. See Charpentier
et al. 2008 for this first-ever demonstration of other-than-genetically transmitted “paternal effects” in a nonhuman primate.
57. Anderson 2006.
58. Hrdy 1979; van Schaik and Dunbar 1990. The relationship between infanticide and male care has been well worked out and tested with comparative evidence from primates (Paul et al. 2000). For an up-to-date review of the now vast literature on primate infanticide, see van Schaik and Janson 2000.
59. Kleiman and Malcolm 1981; Taub 1984; Wright 1984; Paul et al. 2000.
60. For overview, see Marlowe 2001 and references therein.
61. Hewlett 1988, see esp. Tables 16.4 and 16.6. See also Konner 2005 for overview.
62. Hewlett 1992.
63. Reviewed in Hrdy 1999, chs. 7 and 8.
64. Meehan 2005, and personal communication 2007.
65. In addition to the Hadza and Aka case studies discussed here, Meehan has recently extended her fieldwork to include Ngandu horticulturalists living near the Aka (Meehan 2008). Winking and Gurven (2007) also report comparable patterns among Tsimane forager-horticulturalists in Bolivia.
66. Literature reviewed in Konner 2005; Crittenden and Marlowe 2008, Table 1.
67. Crittenden and Marlowe 2008.
68. Marlowe 2005b, Fig. 8.3.
69. Marlowe 2005b:184–185, esp. Fig. 8.2. See also Blurton Jones, Hawkes, and O’Connell 2005a.
70. For a particularly careful recent study of such maneuvering, see Sugiyama and Chacon 2005.
71. Shostak 1976. For more on help from older brothers, see Hagen and Barrett 2007.
72. Draper and Howell 2005.
73. Sugiyama and Chacon 2005.
74. Barron and Lee 2007.
75. Hewlett 1991a:137.
76. Carlson, Russell, et al. 2006; Mota and Sousa 2000; Schradin and Anzenberger 1999; Schradin et al. 2003. For more on endocrine monitoring see French, Bales, et al. 2003.
77. For changes in prolactin and cortisol levels linked to changes in the mother, see Storey et al. 2000. For cortisol’s role in mother-infant attachment, see Fleming and Corter 1988; Fleming et al. 1997.
78. Bronte-Tinkew et al. 2007.
79. Reported from a preliminary study by Hewlett and Alster (n.d., cited in Hewlett 2001).
80. Delahunty et al. 2007; see also Fleming, Corter, Stallings, and Steiner 2002.
81. For increased secretion of prolactin in birds of both sexes engaged in care of nestlings, see Schoesch 1998 and Schoesch et al. 2004. For mammals and general discussion of prolactin “as the hormone of paternity” see Schradin and Anzenberger 1999. For overview see Ziegler 2000; Wynne-Edwards 2001; Gray et al. 2002; Storey, Delahunty, et al. 2006.
82. Storey et al. 2000; Wynne-Edwards and Reburn 2000.
83. See Wynne-Edwards and Timonin 2007 and Almond, Brown, and Keverne 2006 for experiments with various animal models that fail to show any direct causal relationship between prolactin and caring in males.
84. Two decades of this research are summarized in Fleming and Gonzalez 2009.
85. Stallings et al. 2001.
86. Fleming, Corter, et al. 2002; Fleming 2005. My guess is that nurturing potentials will be found among boys as well as men, but boys have not been studied yet.
87. Gray, Kahlenberg, et al. 2002, and references therein.
88. Silk et al. 2005; Silk 2007; Cheney and Seyfarth 2007.
89. Ziegler 2000.
90. Prudom et al. 2008.
91. When Shur et al. 2008 analyzed fecal samples from wild olive baboon males spending time in close association with former consorts, they found that testosterone levels declined during periods when the female was near term or lactating.
92. I rely heavily here on an excellent overview by Wynne-Edwards (2001). Jones and Wynne-Edwards (2001) undertook the key experiments demonstrating the role of prolactin in promoting male responsiveness to displaced pups among highly paternal Djungarian hamsters but not among relatively nonpaternal Siberian hamsters. Unfortunately we do not yet know much about hormonal changes in other apes in response to cues from pregnant females or infants. However, I would expect hormone levels in chimps to be affected, albeit not nearly so much as in men.
93. Bales, Dietz, et al. 2000.
94. Bales, French, and Dietz 2002.
95. Fite et al. 2005.
96. Russell et al. 2004; social opportunism is also typical of other highly social primates, even those who don’t exhibit the same high levels of alloparental care that marmosets do.
97. Dixson and George 1982.
6. MEET THE ALLOPARENTS
1. For example, a sign at the Human Evolution exhibit at the American Museum of Natural History reads: “We owe our creative success to the human brain . . . symbolic consciousness gives us a capacity for spirituality and a shared sense of empathy and morality” (May 15, 2007).
2. Wilson 1975. It’s worth noting that the first meeting of sociobiologists, organized by Richard Alexander and held in Ann Arbor, Michigan, in 1976, was largely devoted to the topic of alloparental care in animals. That organization subsequently morphed into the Human Behavior and Evolution Society (www.HBES.com).
3. Skutch 1935.
4. Reviewed in Hrdy 1976; Packer et al. 1992.
5. Wilson 1975; Ligon and Burt 2004.
6. This estimate for birds is based on 852 species out of 5,143 for which patterns of parental care are actually known (Cockburn 2006: Table 1). This new estimate, based on better field data, is three times higher than the old 3 percent figure cited for so long in the literature (Ligon and Burt 2004; Arnold and Owens 1998). The 3 percent estimate for mammals (see Russell 2004 for a recent review) includes a number of mammals like pine voles and prairie voles that have shared care but do not engage in shared provisioning of young. At the same time, the estimate leaves out many primates with shared care but no provisioning. This is a problem because, on the one hand, ornithologists and entomologists consider shared provisioning an integral part of the definition of “alloparental care,” so voles, etc., should not be included. This makes the 3 percent figure too high. However, if the definition (just shared care) used by those who study voles is used, the current figure, leaving out all the primates that share care, is way too low. Obviously, there is a desperate need for an updated review and standardized terminology. In the interim, “full-fledged cooperative breeding” is used here to describe mammal species with both shared care and extensive provisioning.
7. Hrdy 2005b:69. See esp. König 1994 for more on the facultative reproductive strategies of mice.
8. For correlations of good help with more mouthfuls of food per minute, see Whitten 1983 for primates. For more increased survival of breeding adults see DuPlessis 2004. For correlations of help with reproductive success for breeders, see reviews in Chapters 3 and 5 for primates, and extensive literature for other animals reviewed in Clutton-Brock, Russell, et al. 2001 as well as in the volume edited by Koenig and Dickinson 2004, esp. the chapter by Russell. For adults with help who live longer, see Arnold and Owens 1998; Rowley and Russell 1990. For correlations between calf survival and number of allomothers in the family unit see Lee 1987; Payne 2003.
9. Gittleman 1986.
10. See Jennions and Macdonald 1994, Table 1, and Russell 2004 for reviews of mammalian cases; Koenig and Dickinson 2004 for birds.
11. Reviewed in Pruett-Jones 2004; Clutton-Brock et al. 2003; Heinsohn 1991.
12. Wilson 1975; see also Wilson and Hölldobler 2005:13371.
13. Emlen (1995, 1997) follows in a venerable ornithological tradition of borrowing terminology from human families to describe their flighty study subjects. For an early critique and further discussion of Emlen’s foray into the human family, see Davis and Daly 1997. As yet there has been little response from behavioral scientists who actually study family relations.
14. For example, Solomon and French’s ground-breaking compilation (Cooperative Breeding in Mammals, 1997) does not include humans. Nor do humans appear on the list of cooperatively breeding mammals
in Russell’s 2004 overview. For interesting exceptions see Schaller’s comparisons between early hominins and savanna-dwelling social carnivores like lions and wild dogs (1972:263), or McGrew 1987 for comparisons between the family lives of humans and marmosets, and of course the work of early human sociobiologists like Turke, Flinn, and Hames described in Chapter 3.
15. Hrdy 1999.
16. Clutton-Brock 2002. Today such comparisons are increasingly mentioned at the end of grant proposals for work on the Callitrichidae.
17. African meerkats provide some of the best-documented cases of alloparents that only volunteer when they can afford to (e.g., Russell, Sharpe, et al. 2003).
18. Hrdy 1977a, ch. 7.
19. König 1994; Drea and Frank 2003. On co-suckling specifically involving grandmothers, see Lee 1987 as well as Gadgil and Vijayakumaran Nair 1984 for elephants; Mills 1990 for brown hyenas. Sperm whales may also have communal suckling (Whitehead and Mann 2000:239).
20. König 1994.
21. Creel and Creel 2002.
22. Macdonald 1980; Malcolm and Marten 1982; Moehlman 1983; Asa 1997; Lacey and Sherman 1997. Pregnant females may also be provisioned.
23. Lacey and Sherman (1997) provide an excellent introduction to the extensive literature on naked mole rats.
24. Of the 261 passerine birds, 217 did not ever breed cooperatively, 10 occasionally did so, while 34 species were frequently cooperative. Duration of postfledging nutritional dependence was more than twice as long for those that bred cooperatively than for noncooperators, while the occasional cooperators fell between the two extremes (Langen 2000, Fig. 1).
25. Contrast Langen (2000), who argues the former, with E. Russell (2000), who suspects the latter. Keep in mind however that the two views are not necessarily mutually exclusive.
26. Langen 1996; Rowley 1978.
27. Boran and Heimlich 1999; Rapaport 2006; Rapaport and Brown 2008; Burkart and van Schaik 2009.
28. Malcolm and Marten 1982; Creel and Creel 2002, esp. p. 165; cf. Bogin 1997:72.
29. Thornton and McAuliffe 2006; quotation appears on page 228. See Rapaport 2006 for pied babbler case.
30. Wilson 1971b; Hölldobler and Wilson 1990.
31. For example, see Sherman et al. 1995; Lacey and Sherman 1997. Even though the idea of a “eusociality continuum” remains controversial among some entomologists, I use it here because as Lacey and Sherman (2005) point out, the concept is helpful for facilitating potentially revealing cross-taxonomic comparisons. Such comparisons are a main objective of this chapter.
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