Cooperation, social norm internalization, and hierarchical societies

Abstract

Many animal and human societies exhibit hierarchical structures with different degrees of steepness. Some of these societies also show cooperative behavior, where cooperation means working together for a common benefit. However, there is an increasing evidence that rigidly enforced hierarchies lead to a decrease of cooperation in both human and non-human primates. In this work, we address this issue by means of an evolutionary agent-based model that incorporates fights as social interactions governing a dynamic ranking, communal work to produce a public good, and norm internalization, i.e. a process where acting according to a norm becomes a goal in itself. Our model also includes the perception of how much the individual is going to retain from her cooperative behavior in future interactions. The predictions of the model resemble the principal characteristics of human societies. When ranking is unconstrained, we observe a high concentration of agents in low scores, while a few ones climb up the social hierarchy and exploit the rest, with no norm internalization. If ranking is constrained, thus leading to bounded score differences between agents, individual positions in the ranking change more, and the typical structure shows a division of the society in upper and lower classes. In this case, we observe that there is a significant degree of norm internalization, supporting large fractions of the population cooperating in spite of the rank differences. Our main results are robust with respect to the model parameters and to the type of rank constraint. We thus provide a mechanism that can explain how hierarchy arises in initially egalitarian societies while keeping a large degree of cooperation.

On the interplay of hierarchies, conflicts, and cooperation: An experimental approach

“…The overall structure of the experiment resembles the theoretical model presented in ref. ( 30 ). Three treatments were implemented: egalitarian group, small hierarchy, and large hierarchy, which we describe in detail below.…”

“…In this paper, we study experimentally how individuals in a hierarchical setting behave in a cooperation dilemma when dyadic conflicts are possible. Our starting point is a recent agent-based model ( 30 ) that considers individuals, characterized by their rank, taking part in a collective action problem. Individuals can attack others for the resources they obtained from the common pool; individuals with a higher rank have more probabilities of winning and ranks are readjusted according to the outcome of the competition.…”

Indian caste names and cooperation in the Prisoner’s Dilemma

“…Cooperation across social groups is a prominent area of research in psychology, economics, and evolutionary psychology (Henrich & Muthukrishna, 2021). Although various cultures and diverse social classes across the world have been studied to understand their cooperative behaviour (Lozano et al., 2020; Masuda, 2012; von Rueden et al., 2019), we herein explored cooperation between social groups in a societal system with historically (virtually) hierarchically organised social groups; namely, the Indian caste system. Although past research on the caste system and normative behaviour has supported the long‐standing division of the groups (Brooks et al., 2018; Hoff et al., 2011; Sankaran et al., 2017; Waring, 2015), our preregistered, well‐powered study did not find support for a significant difference in cooperation in a one‐shot cooperation paradigm.…”

“…Cooperation across social groups is a prominent area of research in psychology, economics, and evolutionary psychology (Henrich & Muthukrishna, 2021). Although various cultures and diverse social classes across the world have been studied to understand their cooperative behaviour (Lozano et al, 2020;Masuda, 2012;von Rueden et al, 2019), we herein explored cooperation between social groups in a societal system with Figure 1 Plot displaying the probability of cooperation by the caste group when not controlled for further variables (A) with a member of the different caste group with a 95% confidence band, and (B) with a member of the same caste group with a 95% confidence band.…”

The ecology of wealth inequality in animal societies

“…In cooperation experiments with chimpanzees, bonobos, and cottontop tamarins, evidence suggests that species that divide the rewards of cooperation more equally are more likely to show cooperative behavior [62,63]. Theoretical and empirical studies of collective action problems (e.g., public goods game) suggest that inequality has complex and often unpredictable effects on cooperative behavior [64][65][66][67][68][69][70][71][72]. However, a rough pattern emerges in the literature suggesting that the effect of inequality on cooperation might depend on the type of wealth under consideration.…”