Does Cooperation Really Make It Happen?

What didn’t Sesame Street teach us? Working together (sometimes) makes things go easier—whether you're a part of a group of Muppets who want a community garden, or perhaps hunter-gatherers managing your existence. Humans are the only species to cooperate to the degree that we do, and this cooperation may have allowed for many other derived social traits related to group living to emerge, including generosity, sharing, teaching and learning, and shared intentionality. But how and why did cooperation emerge in the first place? A recent paper in Science by Hill, Walker, and colleagues investigates cooperation in the course of human social and cultural evolution by looking to contemporary hunter-gatherer groups for some of the answers.

Hunter-gatherer societies have long been present in human history. These groups are not static kin-based societies: ethnographic analysis by Hill et. al. show significant and varying shifts in residence patterns, with both male and female dispersal to other groups. The researchers present these findings to counter previously held assertions about the nature of group membership in hunter-gatherer societies:

Traditionally, anthropologists have suggested that hunter-gatherer co-residence is almost entirely bases on kinship [e.g., (15, 16)], and evolutionary psychologists have embraces this idea in order to develop "mismatch hypotheses" about cooperation among non-kin in modern societies (17) (1).

While John Hawks correctly notes that the definition of "traditionally" may be a bit specific in this case, the implications are interesting for social learning.

Alternative models of residence suggest that group benefits may favor non-kin associations. For example, several unaffiliated males between groups linked via the same female could experience decreased hostilities, open cross group visitation, and overall increased interaction between unrelated parties. Larger and more diverse group membership increases opportunities for introducing innovations and preserving these new ideas across generations:

When people reside together, they have frequent opportunities to observe innovations, evaluate their success, and imitate traits judged most successful or common. Our analyses suggest that the increased network size that follows a unique shift in ancestral human residential structure may have led to greater exposure to novel ideas worth copying, and may explain why humans, but not other animals, evolved costly social learning mechanisms (such as high-fidelity over-imitation or conformity-biased transmission) that may have resolved in cumulative cultural evolution (21) (2).

It seems that cooperation is the glue that binds societies together—or tears them apart if revolutions are properly understood. Cooperation then is not the byproduct of contact, but a necessary element to human sociality and relationships. However, we all know that cooperative efforts are far from perfect—too much depends on individual personalities and aspirations. Anyone who has attempted to get a work team to to a shared goal has surely experienced this first hand. That is not to say that there are not obviously differing priorities between corporate groups and hunter-gatherers, but the idea that individual personalities need to be managed should not be overlooked. While brief mention is made in the introductory remarks that "norm violators are punished," this paper would have been strengthened with a discussion on how non-cooperative group members are dealt with in these sorts of societies.

In their conclusions, the researchers also briefly touch upon a nagging point that lingered from the onset: the degree to which modern hunter-gatherer societies are related to ancestral groups is complex. We know that cultural contact changes these groups radically, and that for many, their traditions are fading fast or being transformed into theater for tourism groups. The authors acknowledge that:

Without causal models of residential association that consider the impacts of technology, warfare, cooperative hunting, territorial inheritance, depletion, and demographic crashes, we should be cautious about the use of specific modern groups as analogs for past patterns (3).

Still, they believe that the ethnographic account is robust enough to support their conclusions regarding the development of social structure in relation to cooperation. While we may never know the degree that cooperative tendencies have been impacted by modern contact—even if that contact is simply an awareness of an other—we do know that behaviors change over time as social dynamics shift. While it does seem that cooperation is necessary for group stability, it is unclear what factors decide which behaviors are adopted and which discarded. The correlation between group size and knowledge retention suggests a complex relationship that is not fully explained by cooperation—nonetheless, understanding how the dispersal of kin can impact group dynamics is certainly important in understanding how networks develop.

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Cited:

Hill, K., Walker, R., Bozicevic, M., Eder, J., Headland, T., Hewlett, B., Hurtado, A., Marlowe, F., Wiessner, P., & Wood, B. (2011). Co-Residence Patterns in Hunter-Gatherer Societies Show Unique Human Social Structure Science, 331 (6022), 1286-1289 DOI: 10.1126/science.1199071

HT: Thanks much to Philip Melton (@PEMelton) for sharing this paper and its supplements!

Notes:

1. Hill, Walker, et. al. (2011): 1286. | 2. Hill: 1288 | 3. Hill: 1288