Mothers and Others

by Sarah Blaffer Hrdy

  74. See Haig (1999) for a thoughtful reconstruction of this “deep history.”

  75. Most of the births were triplets, but rarely did more than two survive (McGrew and Barnett 2008).

  76. Data for this correlation derive from three of the best-studied species of Callitrichidae, the moustached tamarin (Saquinus mystax), common marmosets (Callithrix jacchus), and golden lion tamarins (Leontopithecus rosalia). Snowdon 1996; Bales et al. 2002; and Karen Bales, personal communication, January 2008. For detailed field observations on alloparental care and provisioning, see Bales et al. 2000; Baker et al. 2002.

  77. Killing of infants by females other than the mother has now been so frequently observed, both in captivity and the wild (e.g., Digby 2000; Saltzman and Abbott 2005; Saltzman et al. 2008; Bezerra et al. 2007) that Saltzman et al. 2008:282 propose that pregnant female marmosets “routinely” eliminate competitors to their own young.

  78. Digby 2000.

  79. Garber 1997; Porter and Garber (2008) also reported allomaternal food-sharing for Callimico goeldii.

  80. Garber 1997.

  81. Rapaport and Brown 2008; see also Cronin et al. 2005.

  82. Hauser et al. 2003; Cronin et al. 2005; Snowdon and Cronin 2007.

  83. Burkart et al. 2007; see also Burkart and van Schaik 2009 and ongoing research by these authors.

  84. Hauser et al. 2003.

  85. Ziegler et al. 2004, 2006.

  86. Schradin and Anzenberger 1999; Schradin et al. 2003.

  87. Johnson et al. 1991; Bardi et al. 2001. Except for information from macaque monkeys and ape mothers reared in captivity under conditions of social deprivation, there are almost no other observations of infant abuse or abandonment of full-term young among nonhuman primates.

  88. For more detailed examination of this topic, esp. the human evidence, see Hrdy 1999.

  89. Varki and Altheide 2005.

  90. See classic early paper by Lancaster and Lancaster 1987; see Kramer 2005b for a twenty-first-century update.

  91. Kaplan 1994; Kramer 2005a and personal communication, 2005.

  92. Van Schaik 2004; Knott 2001; Robson, van Schaik, and Hawkes 2006.

  93. For nonhuman primates, see Mitani and Watts 1997, Fig. 3; also Ross and MacLarnon 2000. For association between alloparental care and earlier weaning in humans, see Quinlan and Quinlan 2008, Fig. 2.

  94. See Whitten 1983 for the first empirical demonstration of greater feeding efficiency in mothers with help.

  95. See Partridge et al. 2005 on costs of reproduction. See Penn and Smith 2007 specifically for the human case. See Hawkes and Paine 2006 for general discussion.

  96. Coontz 1992. See also Stone 1977 for families in the English-speaking world. See Stack 1974 for mid-twentieth-century black communities in the United States. See Al Awad and Sonuga-Barke 1992 for contemporary Sudan. For traditional societies in South America and Africa see Weisner and Gallimore 1977; Hames 1988; LeVine et al. 1996. For children “at risk” see esp. Crnic et al. 1986; Durrett et al. 1984; Lyons-Ruth et al. 1990; Pope et al. 1993; Werner and Smith 1992; Spieker and Bensley 1994.

  97. Kertzer 1993; Hrdy 1999:371–372.

  98. Crittenden 2001:108–109; Pearse 2005; Rosenbloom 2006; Walker 2006.

  99. Spieker and Bensley 1994.

  100. Furstenberg 1976.

  101. Pope et al. 1993.

  102. Olds et al. 1986, 2002. See overview of many such interventions by Olds et al. 2007.

  103. Coutinho et al. 2005.

  104. Turke 1988; see also Hames 1988, another pioneer in this area.

  105. Flinn (1989) reported that nine Trinidadian mothers living in households with nonreproductive helpers (typically daughters) on hand had significantly higher reproductive success than 29 mothers without such help. See also Hames 1988 for an early study of “helpers at the nest” in tribal South America.

  106. Hawkes, O’Connell, and Blurton Jones 1989.

  107. Hawkes, O’Connell, and Blurton Jones 1997.

  108. Hawkes, O’Connell, et al. 1998.

  109. Hrdy 1999, 2002.

  110. Adovasio et al. 2007.

  111. Ivey 2000; see also Ivey Henry et al. 2005.

  112. Sear et al. 2000, 2002, reanalyzing data first collected in the mid-twentieth century by Dr. Ian McGregor and his collaborators.

  113. Sear et al. 2000:1646.

  114. Sear et al. 2002.

  115. Sear and Mace 2008. How father-absence affected the Mandinka child’s psychological or emotional development is unknown. But for one of the few studies ever to address this issue (and conclude for Western children that the main effect would be closer attachment to the mother), see Golombok et al. 1997.

  116. Across wild populations of prosimians, New and Old World monkeys, and Great Apes, roughly half of all infants born die before adulthood. For example, 50 percent death rates in the first year of life are reported for wild slender loris (Radhakrishna and Singh 2004) and several species of wild tamarins (Wright 1984:71). Similarly high death rates over the first several years are reported for baboons (Altmann 1980:41; Altmann and Alberts 2003) and Great Apes (van Noordwijk and van Schaik 2005; Harcourt and Stewart 2007). Mean death rates in the first year are comparable for other apes and humans, around 22 percent. But mortality at older ages varies tremendously between forager groups. Only after the first year, as humans infants approach weaning and during their juvenile years, do we begin to see a lot of variation. The variation reveals interesting contrasts between humans and other apes, probably having to do with how variable post-weaning maternal and allomaternal provisioning can be in humans (Hill et al. 2001). Consider three samples from Central African foragers. At the low end, 14 percent of Efe infants died in the first year, 22 percent at older ages. By contrast 33 percent of Mbuti infants died in the first year, plus another 56 percent by age 15. Among the Aka, 20 percent of infants born during Hewlett’s fieldwork died in the first 12 months, 43 percent by age fifteen (Hewlett 1991b, 2001, and supplementary data in Marlowe 2001, Table A). See also Gurven and Kaplan 2007.

  117. Strassmann and Gillespie 2007.

  4. NOVEL DEVELOPMENTS

  1. Murray and Trevarthen 1986; Trevarthen 2005.

  2. Henning et al. 2005 and references therein.

  3. Personal communication, 2007. Those interested in this topic should look for forthcoming papers by the Japanese anthropologist Akira Takada at Kyoto University.

  4. Bakeman et al. 1990, Table 2, using data from Mel Konner’s pioneering fieldwork between 1969 and 1970, and during a six-month period in 1975.

  5. Bakeman et al. 1990, Fig. 3.

  6. For correlation with nutritional status, see esp. Valenzuela (1990), who used the Strange Separation test to measure attachment security in a population of low-income Chilean infants. See also Kermoian and Leiderman 1986 for Gusii horticulturalists in Kenya, and van IJzendoorn and Sagi 1999 for an overview.

  7. For example, Kermoian and Leiderman (1986:457) described high levels of childcare among the Gusii as “unusual,” and Ivey (2000:856) referred to the Efe as exemplifying a “unique” childcare system.

  8. Tronick et al. 1992; van IJzendoorn et al. 1992; Hrdy 1999, 2005a; Hewlett and Lamb, eds. 2005; Voland et al., eds. 2005.

  9. See Chisholm (2003) on the connection between theory of mind and the need for infants to cope with contingencies. See also Hrdy 2005a.

  10. I specify monkeys because there are no studies using apes reared with inanimate sources of security comparable to Harry Harlow’s mother-deprived rhesus macaques. And frankly, because of the cruelty such experiments entail, I cannot help but hope comparable studies are never done.

  11. Ainsworth 1978:436.

  12. See Rajecki, Lamb, and Obsmacher 1978, and esp. Ainsworth’s commentary there; Hennighausen and Lyons-Ruth 2005; Trevarthen 2005.

  13. Tronick et al. 1978. For an updated review of the vast literature regarding the infant’s quest for social responses see Thompson 2006.

  14. This phrase from Trevarthen,
cited in Bakeman et al. 1990, an analysis of !Kung infancy. See Trevarthen 2005 for Western children.

  15. Hamlin et al. 2007. The Yale experimenters were primarily interested in the implications of their findings for the development of morality, a topic far beyond the scope of this book. For an elegant and up-to-date discussion, see Hauser 2006.

  16. Tomasello 1999, esp. pp. 61–68; quotation from p. 61.

  17. Harlow’s discovery that “motherless” rhesus monkeys preferred soft, terrycloth-covered surrogates to wire ones with a milk bottle attached only served to confirm Bowlby’s convictions on this score (Bowlby 1971).

  18. See Rilling 2006 for up-to-date overview.

  19. Regarding sensitivity, see Murray and Trevarthen 1986; regarding contingent commitment, see Hrdy 1999, chs. 16, 17, 19 and 20; Hennighausen and Lyons-Ruth 2005, and esp. the writings of Jim Chisholm (1999, 2003).

  20. Draghi-Lorenz et al. 2001; Reddy 2003, 2007. For more on the importance of emotions like pride and shame for the developing sense of self, see Fonagy et al. 2002:25ff.

  21. The only exceptions include some prosimians, such as galagos and ruffed lemurs, who leave their babies in a nest (e.g., Pereira, Klepper, and Symons 1987).

  22. Bowlby 1971; Harlow et al. 1966. For the first experiments designed to test Bowlby’s theories about attachment using rhesus macaques, see Spencer-Booth and Hinde 1971a; 1971b. The first stages of infant distress will be all too familiar for researchers who use Mary Ainsworth’s Strange Situation test, described further in Chapter 9, n. 27.

  23. Robert Hinde, personal communication 1996.

  24. Bowlby 1971. For infant-initiated adoption of new caretakers in a nonhuman primate model, langur moneys, see Dolhinow and Taff 1993.

  25. See Dolhinow 1980 for langur monkey infants separated from mothers. For indiscriminate attachment in emotionally deprived or orphaned human children, see Hennighausen and Lyons-Ruth 2005; O’Connor et al. 2000; and esp. Albus and Dozier 1999.

  26. Thompson et al. 2005; Leckman et al. 2005 and references therein.

  27. Ainsworth 1978:436.

  28. See Fleming and Gonzalez 2009 and references therein for up-to-date review.

  29. Trevarthen and Aitken 2001.

  30. Hrdy 1999, chs. 19 and 20.

  31. Bowlby 1969 (1971 edition).

  32. Bard, Myowa-Yamakoshi, et al. 2005; Keller et al. 1988; Keller 2004.

  33. Lavelli and Fogel 2002:30. See also Papousek and Papousek 1977, who considered this possibility.

  34. Bard, Myowa-Yamakoshi, et al. 2005.

  35. Kaye and Fogel 1980; Locke 1993. See Kojima 2001 for humans. See Hrdy 1977a for monkeys.

  36. Kojima 2001:193.

  37. Kojima 2001.

  38. For the best available descriptions of babbling in pygmy marmosets see Elowson, Snowdon, and Lazaro-Perea 1998a; 1998b. For descriptions of infant vocalizations among wild Goeldi’s monkey (Callimico goeldi) see Masataka 1982.

  39. June 3, 2003, SBH interview with Jeff French.

  40. Elowson et al. 1998b.

  41. For example, Bard 2004, in her discussion of the rarity of “colicky” crying in chimps. Kojima 2001:195, and esp. Nishimura 2006.

  42. Falk 2004a. For background on motherese see Fernald et al. 1989.

  43. Falk 2004b:530, in response to critics pointing out that foraging mothers rarely set babies on the ground.

  44. According to ethnographer Barry Hewlett, when Aka parents take infants with them on hunting expeditions, either parent may briefly put the baby down while actually jumping on netted prey (personal communication 2008).

  45. Strier 1992:84.

  46. Falk 2004a. See related explanation for language origin in Locke and Bogin 2006. The best starting point for readers interested in the primate origins and subsequent evolution of language is Hauser et al. 2002. See also Hauser 1996 for general introduction.

  47. Although outside the scope of this book, there exists an extraordinarily rich—and contentious—literature on when, how, and why language took on its distinctively human properties. Falk (2004a) and I (Hrdy 2005a) rely on a fairly conventional chronology which places the emergence of human language between 50,000 (Klein and Edgar 2002) and 150,000 or so years ago (McBrearty and Brooks 2000). See also Bickerton 2004; Lieberman 2007. Other anthropologists and linguists place the emergence of language earlier and view it as more tightly correlated with babbling.

  48. Scientific accounts of biparental care in titi monkeys and shared care in langurs began to be presented at meetings and to appear in the literature by the 1960s (e.g., Jay 1963; Mason 1966).

  49. Tronick et al. 1992:568; van IJzendoorn, Sagi, and Lambermon 1992. Outside of developmental psychology, attachment theory also had its share of criticism from feminists and others concerned with its implications for mothers, but that is another story, told elsewhere (Hrdy 1999, ch. 22).

  50. Bowlby 1988:2; see esp. also Rutter 1974.

  51. Lamb, Thompson, et al. (1985) following Hinde (1982) were among the first to critique our failure to study the effects of multiple caretakers per se. See also van IJzendoorn, Sagi, and Lambermon 1992 and Ahnert et al. 2006, and references therein.

  52. NICHD Early Child Care Research Network 1997; McCartney 2004. See also ongoing analyses available online (www.nichd.nih.gov, www.excellence-earlychildhood.ca).

  53. See Hewlett 1991a:172 for one of the first discussions of this topic in the context of paternal care among foragers.

  54. See Lamb 1977a for father-infant interactions in the first year of life; 1977b for the second year.

  55. These figures derive from comparison of U.S. “time diaries” kept by four samples of men from 1965, 1975, 1985, and 1998. The average time fathers spent with infants in 1998 was more than twice that of the preceding decades, starting from a low average of 17 minutes a day in the 1960s. (Sayer et al. 2004; see also Lamb 1981; Lamb et al. 1987).

  56. Even among other forest-dwelling hunter-gatherers like the Efe, the proportion of time fathers hold infants is around 2.6 percent. The figure for the veldt-dwelling !Kung is 1.9 percent of daytime. See West and Konner 1976 for the !Kung; Winn et al. 1989 for Efe; see also Hewlett 1988, esp. Tables 16.4 and 16.6; Hewlett 1991b, Table 5; Hewlett 2001; also Katz and Konner 1981.

  57. Werner 1984 and esp. Rutter and O’Connor 1999 for discussion of some of the early practical implementations of this dawning awareness that it was neither unusual nor harmful for children to form several attachments; van IJzendoorn et al. 1992; Sagi et al. 1995.

  58. Van IJzendoorn et al. 1992:5.

  59. Van IJzendoorn et al. 1992. Similar flexibility allowing children to be securely attached to a mother and insecurely attached to an allomother, and vice versa, has since been reported by Lieselotte Ahnert and her coworkers among children in German daycare (Ahnert 2007 and personal communication, 2007, regarding a manuscript in preparation). Assessments of secure vs. insecure attachments rely on Mary Ainsworth’s Strange Situation test, described in Chapter 9, n. 27.

  60. Van IJzendoorn et al. 1992; Sagi et al. 1995.

  61. Specifically, the researchers found less concordance in the child’s relationships across caretakers. This finding from kibbutzim is consistent with U.S. and German studies suggesting that a secure attachment to the mother provides a critical foundation for forging other relationships (Grossmann and Grossmann 2005; Ahnert 2007).

  62. Barry Hewlett, personal communication 2007; Hewlett 2007. See also McKenna et al. 1993; Small 1998.

  63. Fite, French, et al. 2003.

  64. Oppenheim et al. 1990; van IJzendoorn et al. 1992.

  65. For example, Gusii infants securely attached to child caretakers scored significantly higher on the Bayley Mental Development Index than anxiously attached ones (Kermoian and Leiderman 1986:467–468 and Table 3).

  66. Van IJzendoorn and Sagi 1999:723.

  67. For example, the kind of integration Sagi and van IJzendoorn reported was less evident to Ahnert and colleagues (2006) in their study of children
in German daycare centers.

  68. Hewlett and Lamb 2005; Barry Hewlett, personal communication 2008.

  69. Emde et al. 1992; Davis et al. 1994.

  70. Zahn-Waxler, Radke-Yarrow, et al. 1992; Zahn-Waxler, Robinson, and Emde 1992; Warneken and Tomasello 2006.

  71. Draghi-Lorenz et al. 2001; Reddy 2003.

  72. Although “nonbasic emotions” such as pride, shame, or guilt are not thought to emerge until the second year of life, Reddy (2003) and others (Draghi-Lorenz et al. 2001) have argued that they emerge much earlier.

  73. See Nesse 2001, 2007.

  74. Bowlby 1971. See Fonagy et al. 2002 for update on how attachment theorists today view the development of the sense of self.

  75. On forager views of their environment as a “giving place” see Bird-David 1990.

  76. Quotations from Bird-David 1990:190, who reviews this literature based on her own work and that of other ethnographers.

  77. Darnton 1984.

  78. Hewlett, Lamb, et al. 2000, quotation from p. 288.

  79. Hewlett, Lamb, et al. 2000, esp. Tables 1–3.

  80. Clarke-Stewart 1978; Gottlieb 2004:148–164.

  81. See Kramer 2005a for the most detailed empirical study available, based on timed observations in addition to interviews, of how farming shapes patterns of childcare.

  82. Perner, Ruffman, and Leekam 1994.

  83. Harris 2000:54–55ff.

  84. From a study of Han children in a large eastern Chinese city, Fu and Lee 2007, discussed by Burkart 2009.

  85. Perner et al. 1994; Lewis et al. 1996; Ruffman et al. 1998.

  86. Meins et al. 2002.

  87. For the best available introduction to this topic, see Tomasello 1999, esp. pp. 21ff.

  88. Fonagy et al. 2002, quotation from p. 4.

  89. Beuerlein and McGrew 2007.

  90. As in, for example, “the child’s experience of the environment is what counts” (Fonagy et al. 2002:114).