Cooperation in a Larger World

This chapter has three aims. First: it presents a positive account of the origins of multi-level society in human social life, for even the simplest forager bands are nested units in larger communities, and those bands are open, with quite free movement in and out, and with individuals having social allies in other bands. This makes possible cooperation in various guises at larger social and spatial scales. Great ape bands, and hence very likely early hominin bands, were closed, with an individual’s residential group being his/her whole social world. Second, it introduces the reader to group selection models of the evolution of human cooperation. Third, it argues against the view that human social life in the Pleistocene was structured by regular intergroup conflict and by its permanent threat.

The Pleistocene Social Contract

This chapter has three aims (i) it introduces the reader to the evolutionary puzzle of cooperation: why it is relatively rare despite its potential profits; (ii) it offers an account of the transition from the dominance-structured social world of the great apes and earliest hominins to a much more egalitarian and cooperative social order of the small mobile forager band of early to mid-Pleistocene hominins. Their cooperation mostly took the form of immediate return mutualism, and the chapter explains why this form of cooperation is more easily stabilized that reciprocation-dependent cooperation. (iii) It then offers an account of the transition from immediate return mutualism to cooperation through reciprocation: more efficient, potentially more profitable. But less inherently stable. The chapter connects the expansion of cultural learning to the stability of cooperation based on reciprocation.

Cooperation in Hierarchical Communities

This chapter has three interrelated aims: to explain the origins of settled society and farming; the relationship between settled society and the emergence of large and persistent inequalities and the surprising stability of cooperation despite the fact that farming societies tend to become increasingly unequal. That is surprising because of the strength of egalitarian forager norms in the cultures from which farming emergences, because these initially unequal societies have not yet established coercive institutions controlled by elites and because the unequal distribution of resources is clearly against the interests of those outside the elite groups. The chapter offers an account of how elite claims for privilege have initial credibility, and of the erosion of options of collective resistance.

Epilogue: Why Only Us?

The last four chapters have charted the development in our lineage of a coevolutionary loop linking intergenerational information flow and ecological/economic cooperation. The upshot has transformed both human lifeways and the world in which we live. That leaves us with an inevitable question. Once defection is controlled, the profits of information sharing, collective action, the division of labour and exchange are immense. So why have so few species of vertebrates evolved the capacity to exploit those profits? With marginal exceptions, sustained, expensive and extensive cooperation is confined to the hominins. The problem seems to be with the initial establishment of cooperation. As this book shows, once a fairly modest platform of informational and ecological cooperation is built, there are positive feedback loops that can stabilize that cooperation, and in some circumstances expand it. While there is no guarantee that this loop will kick in, once rudimentary cultural learning and cooperation were linked in our lineage, it was not difficult to explain their stabilization and expansion. But cooperative niches are difficult to enter. There are, for example, remarkably few well attested examples of direct reciprocation amongst animals in nature (that is, between animals that are not closely related), even though theory suggests that the conditions under which direct reciprocation are stable should be fairly widespread. All that is necessary is that the two individuals have a high probability of regular future interaction in which each could benefit from the other, plus an environment in which help is cheap to give and valuable to receive (like reciprocal childcare)....

Building Cumulative Culture

This chapter begins with a discussion of methodological issues about historical reconstruction and scenario-building. To what extent can a theory of the emergence of human social behaviour be empirically constrained? What is known (and what is not known) of the behaviour of early humans? The chapter then turns to a substantive project: developing an account of the gradual expansion of cultural learning in the hominin lineage, and of the archaeological signatures of a gradual increase in bandwidth and reliability of that learning. The emphasis in this chapter is the importance of cultural learning in making cooperation increasingly profitable.