Food sharing hypothesis; Hunting hypothesis.
KeywordsNuclear Family Paternal Investment Sexual Division Dependent Offspring Good Hunter
The Male Provisioning Hypothesis (MPH) proposes that men have evolved to provision their mates and children and that this provisioning has resulted in significant changes to the evolution of human biology and life history.
Although the MPH has had many proponents, there have also been many detractors. This article reviews the theoretical underpinnings of the MPH and contrasts the hypothesis with commonly cited alternatives. In reviewing the evidence brought to bear on these alternatives, the article concludes that although male subsistence and provisioning efforts are significantly greater in humans compared to other mammals, the MPH is nonetheless insufficient as a sole explanation for the evolution of humans’ extended life histories and attendant adaptations. Rather, men’s investments in their children and wider communities are flexibly allocated. Human adaptations are more likely the result of a system of cooperative breeding in which any of a variety of possible caretakers subsidizes a lengthy and expensive period of child-rearing.
Provisioning Does Not Require Hunting and Hunting Does Not Require Provisioning
The MPH links together these features in an evolutionary scenario involving: (1) a sexual division of labor in which men primarily acquired meat and women primarily focused on gathering; (2) meat being used by men to provision their mates and biological offspring; (3) a “sex contract” (ibid.) by which women traded fertility for meat; leading to (4) monogamous unions and the establishment of the nuclear family (i.e., a man, his mate, and their dependent offspring) as the elementary human family form. Note that as stated here, the MPH does not require hunting, per se. In fact, in one of the earliest statements of the MPH, Isaac (1978) was careful to distinguish provisioning from hunting, indicating that meat was more likely to have been scavenged than hunted when proto-hominin males began provisioning their mates.
Nevertheless, the MPH has more often been associated with hunting than not (Dart 1953; Gurven and Hill 2009; Gurven and von Rueden 2006; Hill 1982; Kaplan, Hill, Lancaster, and Hurtado 2000; Washburn and Lancaster 1968). Indeed, although the term “male provisioning hypothesis” can be most closely attributed to Owen Lovejoy (1981), the model has its origins in various versions of the “hunting hypothesis” (HH) dating back at least to Westermarck (Westermarck 1903, cited in Kristen Hawkes 2004) and elaborated most influentially by Sherwood Washburn (Hawkes 2004). Washburn’s (Washburn and Lancaster 1968) original arguments foreshadow modern depictions of the MPH: in his view, hunting evolved alongside bipedalism and tool use, and with bigger brains, which reflected the increased skill associated with hunting as opposed to other forms of foraging. Larger brains would have necessitated the birth of immature offspring to avoid taxing the maternal pelvis. This, in turn, led to increased dependency of offspring on their mother and resulted in the need for male provisioning.
Following evidence that bipedalism, brain expansion, and big-game hunting are separated in the paleoarchaeological record by millions of years (Klein 2009), modern variants of the MPH have shifted emphasis away from the broader linkages envisioned by Washburn and others and toward its effects on the human life history, per se. In the most influential version of this argument, Kaplan and colleagues (Kaplan et al. 2000) have proposed that hunting allows for increased investment into “embodied capital” (i.e., skills, knowledge, health), which is accrued during a lengthy period of juvenile dependency, and pays off when skills-intensive foraging (i.e., hunting) increases the reproductive rate of provisioned females. In this view, male provisioning via hunting is the key to underwriting relatively rapid reproduction among human females, as mothers devote the surplus energy to reproduction and childcare rather than foraging (see also Lovejoy 1981). Females offer fidelity to men in exchange and pair-bonds (Gurven and Hill 2009) and nuclear families result (see also Lancaster and Lancaster 1983, 1987; Lovejoy 1981).
Although the MPH and HH are closely related and share certain features in common, it is important to distinguish between them for at least two reasons. First, male provisioning via hunting presumably requires more skill (if not risk) than scavenging or other forms of provisioning and therefore places a stronger emphasis on men’s increased capabilities as being ultimately responsible for shifts in human life histories. As discussed more fully below, this hypothesis continues to inspire debate over the extent to which hunting functions as a means of provisioning hunters’ families (Gurven and Hill 2009; Wood and Marlowe 2014) or whether it serves more commonly to signal status and high quality to nonkin (Bliege Bird and Bird 2008; Kristen Hawkes et al. 2014). Second, male provisioning, whether or not via hunting, is one means by which human allomothers contribute to childrearing. Delineating the factors that predict when and how men invest in children may be more fruitful to our understanding of the origins and maintenance of human life histories than a more narrow focus on hunting, per se.
The male provisioning hypothesis has been at the center of one of the most enduring recent debates in evolutionary anthropology. Although this debate takes different forms, the heart of it concerns (i) the relative contributions to subsistence by males and females and (ii) other possible motivations for male hunting. These two issues have different implications for understanding more generally how men contribute to the evolution of human life history. Undermining the significance of provisioning as a motive for hunting need not imply that men do not or have not in the past chosen to provision their mates. Nor does it need to imply that hunting has lacked an impact on the human life history; even if meat was not used as a form of direct provisioning and was instead widely shared, it would still have been associated with increased energy that could be allocated by women to reproduction instead of foraging (Kaplan et al. 2000; Marlowe 2000). On the other hand, if hunting is not primarily a means of provisioning mates, then pair-bonding and nuclear families do not automatically follow. Moreover, if females are able to supply most of the calories they need in order to subsist, then the degree to which hunting adds to energy reserves is called into question.
Kristen Hawkes (2004) has been perhaps the most vocal critic of the MPH and has provided evidence that supports (i) a stronger role for women in contributing to the diet of hunter-gatherers; and (ii) more self-centered motivations for male hunting than a provisioning model would imply. With respect to (i), evidence suggests that there is more overlap in men’s and women’s subsistence strategies in foraging societies than previously recognized (e.g., Bliege Bird and Bird 2008). This finding is bolstered by cross-cultural evidence of female self-sufficiency in the absence of male support (e.g., Brown 1970; Quinlan and Flinn 2005) and by quantitative evidence of more consistent returns from female rather than male foraging efforts in contemporary hunter-gatherer populations (Bliege Bird and Bird 2008). All of this is not to say that men’s hunting provides negligible dietary input – men contribute as much as 65 % of the calories and 85 % of the protein in forager diets (Cordain et al. 2000; Kaplan et al. 2000) – but it does speak to a more nuanced and flexible system of subsistence than typically advocated by the MPH.
With respect to point (ii), Hawkes and colleagues continue to argue that men’s hunting targets large game that is both widely shared and unpredictably acquired and therefore that men hunt as a means of “showing off” rather than as a form of provisioning (Hawkes and Bliege Bird 2002; Hawkes 1991; Hawkes et al. 2014). In this view, hunting serves as a costly signal that attracts potential mates and allies to good hunters. Meat is not provisioned, but is instead a publicly shared good. Men benefit reproductively from being good hunters, not by investing directly in their wives and children, but by acquiring more or higher-quality mates and allies. Hungry foragers make for an eager audience and the women who contribute to good hunters’ reproductive success also stand to gain, albeit indirectly (e.g., genetically).
Proponents of the show-off model have furnished a variety of evidence in support of its main predictions, including direct evidence that hunters’ wives and children do not receive more shares of hunted meat than do other foragers and by indirect evidence that pair-bond stability is more sensitive to the intensity of male mating competition than by “father effects” related to provisioning (Blurton Jones et al. 2000). Still, data have also supported increased provisioning during critical periods (e.g., lactation) when women are at reduced capacity to meet their own needs (Marlowe 2003) and contradictory interpretations of hunting data from the same society (Kristen Hawkes et al. 2014; Wood and Marlowe 2014), confound resolution. Solving these empirical conflicts will require more data and clarification of the sources of variability in meat apportionment across hunter-gatherer societies. Regardless, the benefits to females of bonding with males are more than just dietary (Scelza 2013), and human males invest significantly in their offspring in a wide variety of contexts (Gray and Anderson 2010), suggesting that these views are not mutually exclusive.
Determinants of Male Parental Investment
Challenges to the hunting hypothesis and earlier iterations of the MPH are sometimes depicted as a more general challenge to the importance of male provisioning in human family systems, but this should not be so. Although the degree to which men help is variable across cultures and less consistent than maternal investment, it is nonetheless significant in relation to the majority of nonhuman primates (Hill 1982 and Fig. 1). Several hypotheses explain when and how intensively men invest in their children, and a wide body of empirical literature has tested these hypotheses (see Gray and Anderson 2010 for review). These tests indicate that fathers invest frequently and significantly under a wide variety of circumstances and even in cultures where the significance of their role is downplayed (Mattison et al. 2014). It is also clear that the means of caring for their children extend far beyond provisioning, including both direct and indirect care (Marlowe 2000) and in relation to the support provided by other caretakers (Gurven and Hill 2009; Kokko and Jennions 2008; Marlowe 2003). Critically, however, the support that fathers provide is sensitive to the subsistence base (Hewlett 1988; Mattison et al. 2014), such that it would be unwise to extend the relationship between paternal investment, monogamy, and nuclear families seen in many contemporary Western societies back into a proto-hominin past.
…‘natural’ parental behavior is often surprisingly flexible, and there are multiple pathways to successful parenting. (Sear 2016, p. 101)
The Male Provisioning Hypothesis in its most virile form has more or less been laid to rest – that is to say, it is no longer generally accepted that men’s hunting alone can explain the adaptive suite that separates humans from nonhuman primates. The current debate centers instead on the relative contributions of fathers, grandmothers, and other kin to the origins and maintenance of our extended life history and relatively rapid reproduction. Whereas it is undeniable that paternal investments in different forms of care (both direct and indirect) underwrite these costs in societies when men benefit reproductively from doing so, it is equally clear that many other care-takers are often as, or more, important (Sear and Mace 2008).
At the same time, the significance of men’s hunting in human evolution is not in doubt. It is now “…largely accepted that successful hunters (1) contribute valuable protein and fats to the diet, (2) gain prestige and social status, and (3) tend to have higher reproductive success than poor hunters” (Gurven and von Rueden 2006, p. 81). In light of the available evidence, it seems likely that hunting involves a variety of functions of which provisioning is only one (see Gurven and Hill 2009). This does not diminish the importance of hunted meat as a source of nutrients for hunter-gatherers, but it would seem to weaken the link between hunting, monogamy, and nuclear family formation.
The MPH and the HH, if questionable in their specifics, have nonetheless been useful frameworks to understand how the support of different caretakers might affect the evolution of human life histories. Indeed, the recognition that provisioning and cooperation have played central roles in extending our life history has led to sophisticated applications of the cooperative breeding hypothesis to understand how various care-providers navigate the costs and benefits of providing care under different circumstances (Sear 2016). And unlike the MPH and HH, the cooperative breeding hypothesis implies nothing about universals in the sexual division of labor or the importance of specific care-takers. Rather, it emphasizes our vast flexibility in caring for our unusually dependent offspring.
- Bliege Bird, R., & Bird, D. W. (2008). Why women hunt: Risk and contemporary foraging in a Western Desert Aboriginal Community. Current Anthropology, 49(4), 655–693. doi:10.1086/587700.Google Scholar
- Blurton Jones, N. G., Marlowe, F. W., Hawkes, K., & O’Connell, J. F. (2000). Paternal investment and hunter-gatherer divorce rates. In L. Cronk, N. Chagnon, & W. Irons (Eds.), Adaptation and human behavior: An anthropological perspective (pp. 69–90). New York: Aldine de Gruyter.Google Scholar
- Dart, R. A. (1953). The predatory transition from ape to man. International Anthropological and Linguistic Review, 1, 201–217.Google Scholar
- Gray, P. B., & Anderson, K. G. (2010). Fatherhood: Evolution and human paternal behavior. Cambridge, MA: Harvard University Press.Google Scholar
- Hawkes, K. (2004). Mating, parenting, and the evolution of human pair bonds. In Kinship and behavior in primates (pp. 443–473). Oxford/New York: Oxford University Press.Google Scholar
- Hewlett, B. S. (1988). Sexual selection and parental investment among Aka Pygmies. In L. Betzig, M. Borgerhoff Mulder, & P. Turke (Eds.), Human reproductive behaviour (pp. 263–276). Cambridge: Cambridge University Press.Google Scholar
- Lancaster, J. B., & Lancaster, C. (1987). The watershed: Change in parental-investment and family-formation strategies in the course of human evolution. In Parenting across the life span: Biosocial dimensions (pp. 187–205). New York: A. de Gruyter.Google Scholar
- Lancaster, J. B., & Lancaster, C. S. (1983). Parental investment: The hominid adaptation. In D. Ortner (Ed.), How humans adapt: Biocultural odyssey (pp. 33–56). Washington, D.C.: Smithsonian Institution Press.Google Scholar
- Washburn, S. L., & Lancaster, C. S. (1968). The evolution of hunting. In R. B. Lee & I. DeVore (Eds.), Man the hunter (pp. 293–303). Chicago: Aldine.Google Scholar