Machiavellian strategist or cultural learner? Mentalizing and learning over development in a resource-sharing game.

Adam Baimel,Joseph Henrich,Susan Birch,Myriam Juda

doi:10.1017/ehs.2021.11

Abstract

Theorists have sought to identify the key selection pressures that drove the evolution of our species' cognitive abilities, life histories and cooperative inclinations. Focusing on two leading theories, each capable of accounting for many of the rapid changes in our lineage, we present a simple experiment designed to assess the explanatory power of both the Machiavellian Intelligence and the Cultural Brain/Intelligence Hypotheses. Children (aged 3-7 years) observed a novel social interaction that provided them with behavioural information that could either be used to outmanoeuvre a partner in subsequent interactions or for cultural learning. The results show that, even after four rounds of repeated interaction and sometimes lower pay-offs, children continued to rely on copying the observed behaviour instead of harnessing the available social information to strategically extract pay-offs (stickers) from their partners. Analyses further reveal that superior mentalizing abilities are associated with more targeted cultural learning - the selective copying of fewer irrelevant actions - while superior generalized cognitive abilities are associated with greater imitation of irrelevant actions. Neither mentalizing capacities nor more general measures of cognition explain children's ability to strategically use social information to maximize pay-offs. These results provide developmental evidence favouring the Cultural Brain/Intelligence Hypothesis over the Machiavellian Intelligence Hypothesis.

Highlights

What are the origins and nature of human sociality and social psychology, and how can we explain this from an evolutionary perspective? Unravelling this puzzle is challenging because evidence from paleontology, archaeology and genetics suggests that our lineage has transformed substantially over the last few million years, including a roughly 3-fold increase in brain size (Bailey & Geary, 2009; Schoenemann, 2006), greater reliance on tools and a substantial shift in our life history with the emergence of middle childhood and a long post-reproductive period prior to senescence (Boyd & Silk, 2012)
To facilitate the application of strategic reasoning in social interactions – game-theoretic thinking – this view holds that humans have evolved greater abilities to represent others’ mental states – mentalizing – and employ these abilities to exploit or manipulate conspecifics (e.g. Byrne & Whiten, 1991).We note that Byrne and Whiten’s (1988) original conceptualization of the Machiavellian Intelligence Hypothesis was broader than what we have presented here including, for example, primates’ skills in managing coalitions; we focus more narrowly on the part of the hypothesis capable of generating the necessary runaway dynamics
We contrasted this analysis with how well children’s behaviour fit the predictions derived from the Machiavellian Intelligence Hypothesis. This approach to analysing our data allows for the possibility that we could find mixed evidence, with the data supporting both sets of predictions and theories

Summary

Introduction

Unravelling this puzzle is challenging because evidence from paleontology, archaeology and genetics suggests that our lineage has transformed substantially over the last few million years, including a roughly 3-fold increase in brain size (Bailey & Geary, 2009; Schoenemann, 2006), greater reliance on tools and a substantial shift in our life history with the emergence of middle childhood and a long post-reproductive period prior to senescence (Boyd & Silk, 2012) Accompanying these rapid changes were energetically costly modifications to the female pelvis, permitting the birthing of large-headed infants, and a reduction in the length of gestation that made human births relatively premature from the perspective of other primates (Boyd & Silk, 2012). We find little support for the formally modelled version of the Machiavellian Intelligence Hypothesis (McNally and Jackson, 2013), which when applied to humans proposes that our cognitive abilities, along with other anatomical changes, were driven by an arms race in strategic social reasoning

Methods

Results

Conclusion