Life History Theory has proven to be a powerful theoretical framework for understanding the trade-offs that humans face in the allocation of finite resources at developmental and evolutionary levels that shaped the characteristic course of the human life span with prolonged childhood and long life span after menopause ((Brumbach et al. Reference Brumbach, Figueredo and Ellis2009; Hawkes et al. Reference Hawkes, O'Connell, Blurton Jones, Kappeler and Pereira2003; Hill & Hurtado Reference Hill and Hurtado1996; Kaplan & Gangestad Reference Kaplan, Gangestad and Buss2005; Kramer Reference Kramer2005). Van Lange et al. add important perspectives to understanding violence in that the behavioral correlates of faster life histories in the CLASH model have the potential to generate aggression.
What the CLASH model overlooks in its parsimony is that adaptations to the threats posed by the key variables in the model – average temperature and seasonal variation – are mitigated by cultural institutions that increase predictability, reduce risks, and promote stability in human societies. There is no direct causal link between temperature, seasonal variation, and human behavior, because cultural institutions modify human responses to climactic conditions (Henrich Reference Henrich2015b). As Pinker (Reference Pinker2011) has shown, it is the development of cultural institutions over the last centuries that has greatly reduced violence.
I will draw on two examples to illustrate how cultural institutions structure fast or slow life strategies, time orientation, and self-control. The first comes from the Ju/'hoansi Bushmen of the Kalahari who live at 19.5°S. Temperatures are high for all but four months each year, environment is harsh, and resources highly variable in both time and space. The foraging way of life and unpredictable environment preclude storage of surplus for lean times. Cultural adaptations include networks formed by gift exchange partnerships that extend within a 200-km radius (Wiessner Reference Wiessner, Leacock and Lee1982). These involve relationships of mutual support and access to alternate residences that mitigate the risks that might favor a fast life history.
Exchange partnerships are based on marriage ties, as the Ju/'hoansi say: “Marriage is far too important to be left to the young.” Until recently, marriages were arranged before or around puberty to minimize aggressive male competition and build desired social ties, a practice widely found in hunter-gatherer societies. After the birth of the first child, divorce rates were low and extramarital affairs infrequent, for fear of damaging crucial social ties (Howell Reference Howell2000; Lee Reference Lee1979). Birth spacing was wide, allowing for substantial investment in children. Because peaceful relations were essential to mobility, Ju/'hoansi deplored violence of any kind and emphasized self-restraint. Most disputes were solved by talk or dispersal until tempers cooled (Wiessner Reference Wiessner, Leacock and Lee1982). Moreover, what appears to be present orientation and lack of efficiency in time use is misleading. The Ju/'hoan foraging economy does not allow for storage of food or wealth; people store in social ties. A great deal of leisure time was spent cultivating and maintaining such relationships in pursuit of life-long social security (Wiessner Reference Wiessner, Leacock and Lee1982). As in many traditional societies, “relationships structure time” time is taken to get essential relationships right. In Western societies, where people insure and advance themselves through storage or savings, time is money, and the converse is true. Time spent on social relationships may be rationed such that “time structures relationships.”
The Enga of highland Papua New Guinea, who live at 5.5°S in a temperate climate, provide another example. Resources are abundant and predictable, with minimal seasonal variation, allowing for substantial surplus production and aggressive status competition. Cultural institutions structure the trade-offs in Enga life. Until the past few decades, exogamous marriages were arranged to build social networks outside the clan; promiscuity was severely sanctioned. Separate men's and women's houses, crafted for politics, also allowed for female choice over reproduction, wide birth spacing, and high investment in children. Bouts of interclan warfare were frequent, though contained through institutions for peacemaking. Although violence was socially sanctioned in certain contexts, young men were strictly disciplined and controlled by elders through a series of initiations, as they were in many New Guinea cultures (Wiessner & Tumu Reference Wiessner and Tumu1998). Needs from birth to death were met by the clan, while wealth from outside the clan was obtained through female ties. Future orientation was expressed by investing in these long-term social relationships. Life history was slow.
Similar examples of the mitigation of risks related to climate and society through cultural institutions abound in anthropology, raising questions about the value of any model that directly links average temperature and seasonal variation in temperature to violence. The dissolution of many cultural institutions with colonization, missions, and involvement in the global economy has had a major impact on the trade-offs that individuals face in allocation of resources over the life span. For example, for the Enga the discontinuation of male initiations and the introduction of high-powered weapons has reversed the male age power hierarchy, resulting in reduced self-control and higher rates of rates of murder, rape, and other forms of crime, despite recent reduction in tribal fighting (Wiessner & Pupu Reference Wiessner and Pupu2012). Marriage traditions have broken down, fathers are often absent, women seek men with money, and sex is negotiated at an early age through mobile phones. These factors lead to a faster life history for some.
The turmoil in Enga resembles that occurring in many societies today. It is due partially to the gap created by the dissolution of traditional institutions without replacement by fully functioning democratic institutions, court systems, and culturally appropriate education. The association between climate and violence in the CLASH model may in part be the product of the history of the breakdown of indigenous cultural institutions and the degree of replacement by modern systems of governance. With notable exceptions, countries further from the equator, such as those in Europe, are further ahead in this process than countries closer to the equator, such as those in Central America and Middle Africa.
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Life History Theory has proven to be a powerful theoretical framework for understanding the trade-offs that humans face in the allocation of finite resources at developmental and evolutionary levels that shaped the characteristic course of the human life span with prolonged childhood and long life span after menopause ((Brumbach et al. Reference Brumbach, Figueredo and Ellis2009; Hawkes et al. Reference Hawkes, O'Connell, Blurton Jones, Kappeler and Pereira2003; Hill & Hurtado Reference Hill and Hurtado1996; Kaplan & Gangestad Reference Kaplan, Gangestad and Buss2005; Kramer Reference Kramer2005). Van Lange et al. add important perspectives to understanding violence in that the behavioral correlates of faster life histories in the CLASH model have the potential to generate aggression.
What the CLASH model overlooks in its parsimony is that adaptations to the threats posed by the key variables in the model – average temperature and seasonal variation – are mitigated by cultural institutions that increase predictability, reduce risks, and promote stability in human societies. There is no direct causal link between temperature, seasonal variation, and human behavior, because cultural institutions modify human responses to climactic conditions (Henrich Reference Henrich2015b). As Pinker (Reference Pinker2011) has shown, it is the development of cultural institutions over the last centuries that has greatly reduced violence.
I will draw on two examples to illustrate how cultural institutions structure fast or slow life strategies, time orientation, and self-control. The first comes from the Ju/'hoansi Bushmen of the Kalahari who live at 19.5°S. Temperatures are high for all but four months each year, environment is harsh, and resources highly variable in both time and space. The foraging way of life and unpredictable environment preclude storage of surplus for lean times. Cultural adaptations include networks formed by gift exchange partnerships that extend within a 200-km radius (Wiessner Reference Wiessner, Leacock and Lee1982). These involve relationships of mutual support and access to alternate residences that mitigate the risks that might favor a fast life history.
Exchange partnerships are based on marriage ties, as the Ju/'hoansi say: “Marriage is far too important to be left to the young.” Until recently, marriages were arranged before or around puberty to minimize aggressive male competition and build desired social ties, a practice widely found in hunter-gatherer societies. After the birth of the first child, divorce rates were low and extramarital affairs infrequent, for fear of damaging crucial social ties (Howell Reference Howell2000; Lee Reference Lee1979). Birth spacing was wide, allowing for substantial investment in children. Because peaceful relations were essential to mobility, Ju/'hoansi deplored violence of any kind and emphasized self-restraint. Most disputes were solved by talk or dispersal until tempers cooled (Wiessner Reference Wiessner, Leacock and Lee1982). Moreover, what appears to be present orientation and lack of efficiency in time use is misleading. The Ju/'hoan foraging economy does not allow for storage of food or wealth; people store in social ties. A great deal of leisure time was spent cultivating and maintaining such relationships in pursuit of life-long social security (Wiessner Reference Wiessner, Leacock and Lee1982). As in many traditional societies, “relationships structure time” time is taken to get essential relationships right. In Western societies, where people insure and advance themselves through storage or savings, time is money, and the converse is true. Time spent on social relationships may be rationed such that “time structures relationships.”
The Enga of highland Papua New Guinea, who live at 5.5°S in a temperate climate, provide another example. Resources are abundant and predictable, with minimal seasonal variation, allowing for substantial surplus production and aggressive status competition. Cultural institutions structure the trade-offs in Enga life. Until the past few decades, exogamous marriages were arranged to build social networks outside the clan; promiscuity was severely sanctioned. Separate men's and women's houses, crafted for politics, also allowed for female choice over reproduction, wide birth spacing, and high investment in children. Bouts of interclan warfare were frequent, though contained through institutions for peacemaking. Although violence was socially sanctioned in certain contexts, young men were strictly disciplined and controlled by elders through a series of initiations, as they were in many New Guinea cultures (Wiessner & Tumu Reference Wiessner and Tumu1998). Needs from birth to death were met by the clan, while wealth from outside the clan was obtained through female ties. Future orientation was expressed by investing in these long-term social relationships. Life history was slow.
Similar examples of the mitigation of risks related to climate and society through cultural institutions abound in anthropology, raising questions about the value of any model that directly links average temperature and seasonal variation in temperature to violence. The dissolution of many cultural institutions with colonization, missions, and involvement in the global economy has had a major impact on the trade-offs that individuals face in allocation of resources over the life span. For example, for the Enga the discontinuation of male initiations and the introduction of high-powered weapons has reversed the male age power hierarchy, resulting in reduced self-control and higher rates of rates of murder, rape, and other forms of crime, despite recent reduction in tribal fighting (Wiessner & Pupu Reference Wiessner and Pupu2012). Marriage traditions have broken down, fathers are often absent, women seek men with money, and sex is negotiated at an early age through mobile phones. These factors lead to a faster life history for some.
The turmoil in Enga resembles that occurring in many societies today. It is due partially to the gap created by the dissolution of traditional institutions without replacement by fully functioning democratic institutions, court systems, and culturally appropriate education. The association between climate and violence in the CLASH model may in part be the product of the history of the breakdown of indigenous cultural institutions and the degree of replacement by modern systems of governance. With notable exceptions, countries further from the equator, such as those in Europe, are further ahead in this process than countries closer to the equator, such as those in Central America and Middle Africa.