Humans
umansLETTER
Katharina Hamann1, Felix Warneken2, Julia R. Greenberg3 & Michael Tomasello1
doi:10.1038/nature10278
Collaboration encourages equal sharing in children but not in chimpanzees
Humans actively share resources with one another to a much greater degree than do other great apes, and much human sharing is governed by social norms of fairness and equity1–3. When in receipt of a windfall of resources, human children begin showing tendencies towards equitable distribution with others at five to seven years of age4–7. Arguably, however, the primordial situation for human sharing of resources is that which follows cooperative activities such as collaborative foraging, when several individuals must share the spoils of their joint efforts8–10. Here we show that children of around three years of age share with others much more equitably in collaborative activities than they do in either windfall or parallel-work situations. By contrast, one of humans’ two nearest primate relatives, chimpanzees (Pan troglodytes), ‘share’ (make food available to another individual) just as often whether they have collaborated with them or not. This species difference raises the possibility that humans’ tendency to distribute resources equitably may have its evolutionary roots in the sharing of spoils after collaborative efforts. Among great apes, only humans are true collaborative foragers8,9,11. Other apes forage in small parties, but they do not actively work together jointly to produce food—the only exception being chimpanzee grouphunting of monkeys12,13. In contrast, humans in all societies produce significant portions of their food through collaborative efforts, even bringing the results of their labour back to some central location to share with other group members14,15. After group-hunting, chimpanzees mostly share only under pressure of harassment by others16 or else reciprocally with coalition partners17. Human children actively share valuable resources with others to
Katharina Hamann1, Felix Warneken2, Julia R. Greenberg3 & Michael Tomasello1
doi:10.1038/nature10278
Collaboration encourages equal sharing in children but not in chimpanzees
Humans actively share resources with one another to a much greater degree than do other great apes, and much human sharing is governed by social norms of fairness and equity1–3. When in receipt of a windfall of resources, human children begin showing tendencies towards equitable distribution with others at five to seven years of age4–7. Arguably, however, the primordial situation for human sharing of resources is that which follows cooperative activities such as collaborative foraging, when several individuals must share the spoils of their joint efforts8–10. Here we show that children of around three years of age share with others much more equitably in collaborative activities than they do in either windfall or parallel-work situations. By contrast, one of humans’ two nearest primate relatives, chimpanzees (Pan troglodytes), ‘share’ (make food available to another individual) just as often whether they have collaborated with them or not. This species difference raises the possibility that humans’ tendency to distribute resources equitably may have its evolutionary roots in the sharing of spoils after collaborative efforts. Among great apes, only humans are true collaborative foragers8,9,11. Other apes forage in small parties, but they do not actively work together jointly to produce food—the only exception being chimpanzee grouphunting of monkeys12,13. In contrast, humans in all societies produce significant portions of their food through collaborative efforts, even bringing the results of their labour back to some central location to share with other group members14,15. After group-hunting, chimpanzees mostly share only under pressure of harassment by others16 or else reciprocally with coalition partners17. Human children actively share valuable resources with others to