The eminent evolutionary biologist William D. Hamilton once told me a new hypothesis he had developed: that some ants had religion, of a sort. His idea was that unicoloniality, the development of massive super-colonies spanning hundreds of kilometers where every ant was accepted as colony-mate by every other, was caused by infection with a virus that caused them to lose their ability to recognize kin. The virus would benefit through increased spread, and the ants could benefit from enhanced large-scale cooperation among themselves. Everyone wins – except of course ants that are uninfected.
Hamilton's hypothesis may be more metaphor than reality, but it raises intriguing questions about similarities between humans and social insects. Years later, I wrote an article entitled “The Insectan Apes” (Crespi Reference Crespi2014), which drew together the evidence regarding convergences between humans and social insects that may help explain their shared, spectacular ecological and evolutionary successes. Most of the similarities apply to human hunter-gatherer groups, within which we have spent most of our evolutionary history, and many are economic. They include: (1) life in cooperative groups with unique identities (semiochemicals or culture); (2) central place foraging; (3) extensive food sharing within groups; (4) highly diversified, and high-quality, foods; (5) divisions of labor, including extensive non-maternal care; (6) increased reproduction by females; relative to ancestral forms; (7) collective, cooperative decision making within groups; and (8) the group itself becoming a basic, necessary, social-ecological resource that enhances survival and reproduction.
What these remarkable similarities show is that human groups were behaviorally, ecologically, and economically similar to social insects well before the spread of agriculture. During the agricultural revolutions of humans and social insects, as described by Gowdy & Krall (G&K), further similarities ensued: Both groups developed larger colony sizes, with more-extensive divisions of labor and interdependencies among workers. These convergences indicate that humans and social insects have shared a broadly overlapping suite of selective pressures for millennia, especially with regard to colony-level selection, which corresponds, in humans, to selection among different cultural groups (Aunger & Greenland Reference Aunger and Greenland2014; Crespi Reference Crespi2014; Kesebir Reference Kesebir2012).
Ant religions aside, humans are also divergent from social insects in several fundamental ways that must temper comparisons. First, as noted by G&K, human agriculture led to decreased food sharing, and reduced collectivity in decisions, due in large part to hierarchies of power and wealth. The key difference here is that social-insect divisions of labor, especially in large-colony forms like ants and termites with agriculture, are virtually purely cooperative; by contrast, human divisions of labor are driven predominantly by competition. Social insects cooperate due to coincidence of genetic interest between workers and the queen, through whom all colony members reproduce (Alexander et al. Reference Alexander, Noonan, Crespi, Sherman, Jarvis and Alexander1991). This social-insect economy thus resembles a utopian mix of Marxism and monarchy, with minimal or no incentives, or ability, to engage in selfish reproductive cheating. Where such cheating is possible, it is normally suppressed by policing: For example, in honeybees, if a worker lays an egg, it will almost invariably be eaten by other workers, who gain (as does the colony) by such “moral” behavior. It is only when human groups are threatened from outside, by culturally different groups, that their interests so strongly converge.
Competitive divisions of labor, unlike cooperative divisions of labor in ants and termites, lead directly to inequalities in resources and reproduction, as exemplified by the unbridled reproductive extremes of early city-state rulers (e.g., Betzig Reference Betzig2014). But such inequalities are themselves inequitable, applying more to male than female humans. Herein we find a second key divergence of humans from social insects: Insect queens can evolve greatly increased fecundity by making many, tiny juveniles that are reared by workers, but humans, as mammals, are severely constrained in reproductive potential. Human females have evolved higher fecundity than other great apes, mainly through a halving of inter-birth interval combined with alloparental care (Crespi Reference Crespi2014), but it pales in comparison to ant or termite queens; human juveniles also appear much more expensive to rear than juveniles of other apes.
Reproduction by all females precludes human reproductive division of labor, and indeed, human groups almost certainly benefit at the cultural group level from high fecundity of their female members (Crespi Reference Crespi2014). But competitive reproduction among females as well as males, like competitive divisions of labor, decreases the potential for cooperation within groups. Moreover, human groups exhibit much lower within-group relatednesses than do social insects, and relatedness among interactants drops precipitously with agriculture-driven increases in group sizes. What is an insectan ape to do?
Enter culture, our human-evolutionary trump card, and re-enter religion. Primary effects of religious cognition, behavior, and institutions include the generation of psychological kinship, the unification of within-group interests, and the establishment of moral codes to suppress cheating (Aunger & Greenland Reference Aunger and Greenland2014; Crespi & Summers Reference Crespi and Summers2014). With the emergence of agriculture, human groups increased greatly in size, and religions and gods also got big, as monotheistic, highly moralizing religions supplanted their predecessors (Norenzayan Reference Norenzayan2013). After agriculture, human nation-states, and monotheistic religions became well established, humans also began to adopt a new cultural means of suppressing inequalities: socially imposed monogamy (Alexander Reference Alexander1987).
What is interesting about religion, and imposed restriction of reproduction, is that they represent forms of prosocial, social-insectan adaptation. The first is a marker and driver for group unity, cooperation, altruism, large-scale “kinship,” and colony membership, just like a colony odor in ants, termites, or bees. The second is a reproductive leveler, that reduces competition within both families and human cultural groups (Bowles Reference Bowles2006; Henrich et al. Reference Henrich, Boyd and Richerson2012), like policing in social insects; human families also thus become more similar to the enlarged nuclear-family structure that typifies insect sociality (Alexander et al. Reference Alexander, Noonan, Crespi, Sherman, Jarvis and Alexander1991).
How many human social ills can further be alleviated by emulating the ants and termites underfoot? G&K are to be applauded for their synthesis of economics with social behavior and human history. We are fortunate to differ from social insects in this final key trait: the ability to think, create, plan, and lead, and thus determine our fates.
The eminent evolutionary biologist William D. Hamilton once told me a new hypothesis he had developed: that some ants had religion, of a sort. His idea was that unicoloniality, the development of massive super-colonies spanning hundreds of kilometers where every ant was accepted as colony-mate by every other, was caused by infection with a virus that caused them to lose their ability to recognize kin. The virus would benefit through increased spread, and the ants could benefit from enhanced large-scale cooperation among themselves. Everyone wins – except of course ants that are uninfected.
Hamilton's hypothesis may be more metaphor than reality, but it raises intriguing questions about similarities between humans and social insects. Years later, I wrote an article entitled “The Insectan Apes” (Crespi Reference Crespi2014), which drew together the evidence regarding convergences between humans and social insects that may help explain their shared, spectacular ecological and evolutionary successes. Most of the similarities apply to human hunter-gatherer groups, within which we have spent most of our evolutionary history, and many are economic. They include: (1) life in cooperative groups with unique identities (semiochemicals or culture); (2) central place foraging; (3) extensive food sharing within groups; (4) highly diversified, and high-quality, foods; (5) divisions of labor, including extensive non-maternal care; (6) increased reproduction by females; relative to ancestral forms; (7) collective, cooperative decision making within groups; and (8) the group itself becoming a basic, necessary, social-ecological resource that enhances survival and reproduction.
What these remarkable similarities show is that human groups were behaviorally, ecologically, and economically similar to social insects well before the spread of agriculture. During the agricultural revolutions of humans and social insects, as described by Gowdy & Krall (G&K), further similarities ensued: Both groups developed larger colony sizes, with more-extensive divisions of labor and interdependencies among workers. These convergences indicate that humans and social insects have shared a broadly overlapping suite of selective pressures for millennia, especially with regard to colony-level selection, which corresponds, in humans, to selection among different cultural groups (Aunger & Greenland Reference Aunger and Greenland2014; Crespi Reference Crespi2014; Kesebir Reference Kesebir2012).
Ant religions aside, humans are also divergent from social insects in several fundamental ways that must temper comparisons. First, as noted by G&K, human agriculture led to decreased food sharing, and reduced collectivity in decisions, due in large part to hierarchies of power and wealth. The key difference here is that social-insect divisions of labor, especially in large-colony forms like ants and termites with agriculture, are virtually purely cooperative; by contrast, human divisions of labor are driven predominantly by competition. Social insects cooperate due to coincidence of genetic interest between workers and the queen, through whom all colony members reproduce (Alexander et al. Reference Alexander, Noonan, Crespi, Sherman, Jarvis and Alexander1991). This social-insect economy thus resembles a utopian mix of Marxism and monarchy, with minimal or no incentives, or ability, to engage in selfish reproductive cheating. Where such cheating is possible, it is normally suppressed by policing: For example, in honeybees, if a worker lays an egg, it will almost invariably be eaten by other workers, who gain (as does the colony) by such “moral” behavior. It is only when human groups are threatened from outside, by culturally different groups, that their interests so strongly converge.
Competitive divisions of labor, unlike cooperative divisions of labor in ants and termites, lead directly to inequalities in resources and reproduction, as exemplified by the unbridled reproductive extremes of early city-state rulers (e.g., Betzig Reference Betzig2014). But such inequalities are themselves inequitable, applying more to male than female humans. Herein we find a second key divergence of humans from social insects: Insect queens can evolve greatly increased fecundity by making many, tiny juveniles that are reared by workers, but humans, as mammals, are severely constrained in reproductive potential. Human females have evolved higher fecundity than other great apes, mainly through a halving of inter-birth interval combined with alloparental care (Crespi Reference Crespi2014), but it pales in comparison to ant or termite queens; human juveniles also appear much more expensive to rear than juveniles of other apes.
Reproduction by all females precludes human reproductive division of labor, and indeed, human groups almost certainly benefit at the cultural group level from high fecundity of their female members (Crespi Reference Crespi2014). But competitive reproduction among females as well as males, like competitive divisions of labor, decreases the potential for cooperation within groups. Moreover, human groups exhibit much lower within-group relatednesses than do social insects, and relatedness among interactants drops precipitously with agriculture-driven increases in group sizes. What is an insectan ape to do?
Enter culture, our human-evolutionary trump card, and re-enter religion. Primary effects of religious cognition, behavior, and institutions include the generation of psychological kinship, the unification of within-group interests, and the establishment of moral codes to suppress cheating (Aunger & Greenland Reference Aunger and Greenland2014; Crespi & Summers Reference Crespi and Summers2014). With the emergence of agriculture, human groups increased greatly in size, and religions and gods also got big, as monotheistic, highly moralizing religions supplanted their predecessors (Norenzayan Reference Norenzayan2013). After agriculture, human nation-states, and monotheistic religions became well established, humans also began to adopt a new cultural means of suppressing inequalities: socially imposed monogamy (Alexander Reference Alexander1987).
What is interesting about religion, and imposed restriction of reproduction, is that they represent forms of prosocial, social-insectan adaptation. The first is a marker and driver for group unity, cooperation, altruism, large-scale “kinship,” and colony membership, just like a colony odor in ants, termites, or bees. The second is a reproductive leveler, that reduces competition within both families and human cultural groups (Bowles Reference Bowles2006; Henrich et al. Reference Henrich, Boyd and Richerson2012), like policing in social insects; human families also thus become more similar to the enlarged nuclear-family structure that typifies insect sociality (Alexander et al. Reference Alexander, Noonan, Crespi, Sherman, Jarvis and Alexander1991).
How many human social ills can further be alleviated by emulating the ants and termites underfoot? G&K are to be applauded for their synthesis of economics with social behavior and human history. We are fortunate to differ from social insects in this final key trait: the ability to think, create, plan, and lead, and thus determine our fates.