- Oxford Library of Psychology
- Oxford Library of Psychology
- About the Editors
- Toward Bridging Gaps: Finding Commonality between Evolutionary and Comparative Psychology
- Why Behaviorism Isn't Satanism
- Confronting Language, Representation, and Belief: A Limited Defense of Mental Continuity
- Evolved Cognitive Adaptations
- Convergent Evolution of Cognition in Corvids, Apes and Other Animals
- Social Complexity and Intelligence
- Cephalopod Intelligence
- Cold-Blooded Cognition: Reptilian Cognitive Abilities
- Cetacean Cognitive Specializations
- Socio-Cognitive Specializations in Nonhuman Primates: Evidence from Gestural Communication
- The Evolution of Canine Cognition
- Episodic Memory and Planning
- Comparative Mental Time Travel: Is There a Cognitive Divide between Humans and Animals in Episodic Memory and Planning?
- Animal Models of Human Cognition
- Metacognition across Species
- Symbolic Communication in the Grey Parrot
- Communication in Nonhuman Primates
- Female Preference Functions Provide a Window into Cognition, the Evolution of Communication, and Speciation in Plant-Feeding Insects
- Apes and the Evolution of Language: Taking Stock of 40 Years of Research
- The Phylogeny and Ontogeny of Prosocial Behavior
- The Ontogeny and Phylogeny of Cooperation
- Culture and the Evolution of Human Sociality
- The Evolution of Morality: Which Aspects of Human Moral Concerns Are Shared With Nonhuman Primates?
- The Evolutionary and Comparative Psychology of Social Learning and Culture
- Cognitive Imitation: Insights into the Development and Evolution of Social Learning
- The Ecology and Evolution of Social Behavior and Cognition in Primates
- The Evolution of a Cooperative Social Mind
- Darwin, Tinbergen, and the Evolution of Comparative Cognition
- Comparative Evolutionary Psychology: A United Discipline for the Study of Evolved Traits
Abstract and Keywords
The social brain hypothesis (SBH) offers a framework for integrating evolutionary and social psychological perspectives on human social complexity. SBH offers an explanation for the evolution of unusually large brains among primates and we outline briefly the background theory and evidence. SBH predicts a natural community size of ∼150 for modern humans, and there is now considerable evidence confirming that this is the typical size of both personal social networks and key types of human community. Human communities are highly structured, with a distinct signature of grouping levels that scale with a ratio of ∼3 (i.e., layers at 5, 15, 50, 150, etc.). We argue that the layering arises from a trade-off between the costs of maintaining relationships (a linear function of time spent interacting) and the benefits that accrue from a particular level of investment (an asymptotic function of time). We suggest that trust is a particularly important mechanism in the stability and functionality of relationships.
R. I. M. Dunbar, Institute of Cognitive Evolutionary Anthropology, Oxford University, UK.
A. G. Sutcliffe, Manchester Business School, Manchester, UK.
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