The Social Brain Hypothesis and Human Evolution

2016 ◽  
Author(s):  
Robin I. M. Dunbar
Keyword(s):  
Group Size ◽  
Brain Size ◽  
Dual Process ◽  
Human Cognition ◽  
Social Brain ◽  
Behavioral Complexity ◽  
Cognitive Component ◽  
Hominin Evolution ◽  
The Social ◽  
Primate Sociality

Primate societies are unusually complex compared to those of other animals, and the need to manage such complexity is the main explanation for the fact that primates have unusually large brains. Primate sociality is based on bonded relationships that underpin coalitions, which in turn are designed to buffer individuals against the social stresses of living in large, stable groups. This is reflected in a correlation between social group size and neocortex size in primates (but not other species of animals), commonly known as the social brain hypothesis, although this relationship itself is the outcome of an underlying relationship between brain size and behavioral complexity. The relationship between brain size and group size is mediated, in humans at least, by mentalizing skills. Neuropsychologically, these are all associated with the size of units within the theory of mind network (linking prefrontal cortex and temporal lobe units). In addition, primate sociality involves a dual-process mechanism whereby the endorphin system provides a psychopharmacological platform off which the cognitive component is then built. This article considers the implications of these findings for the evolution of human cognition over the course of hominin evolution.

Social Brain, Distributed Mind

2010 ◽  
Keyword(s):  
Material Culture ◽  
Distributed Cognition ◽  
Small World ◽  
Human Cognition ◽  
Social Brain ◽  
Social Lives ◽  
Hominin Evolution ◽  
Language Technology ◽  
The Social ◽  
Spatially Distributed

To understand who we are and why we are, we need to understand both modern humans and the ancestral stages that brought us to this point. The core to that story has been the role of evolving cognition — the social brain — in mediating the changes in behaviour that we see in the archaeological record. This volume brings together two powerful approaches — the social brain hypothesis and the concept of the distributed mind. The volume compares perspectives on these two approaches from a range of disciplines, including archaeology, psychology, philosophy, sociology and the cognitive and evolutionary sciences. A particular focus is on the role that material culture plays as a scaffold for distributed cognition, and how almost three million years of artefact and tool use provides the data for tracing key changes in areas such as language, technology, kinship, music, social networks and the politics of local, everyday interaction in small-world societies. A second focus is on how, during the course of hominin evolution, increasingly large spatially distributed communities created stresses that threatened social cohesion. This volume offers the possibility of new insights into the evolution of human cognition and social lives that will further our understanding of the relationship between mind and world.

scholarly journals Assessing sources of error in comparative analyses of primate behavior: Intraspecific variation in group size and the social brain hypothesis

2016 ◽  
Vol 94 ◽  
pp. 126-133 ◽  
Author(s):  
Aaron A. Sandel ◽  
Jordan A. Miller ◽  
John C. Mitani ◽  
Charles L. Nunn ◽  
Samantha K. Patterson ◽  
...  
Keyword(s):  
Group Size ◽  
Intraspecific Variation ◽  
Primate Behavior ◽  
Social Brain ◽  
Comparative Analyses ◽  
Sources Of Error ◽  
The Social

The Social Brain

2021 ◽  
pp. 109-122
Author(s):  
Susan D. Healy
Keyword(s):  
Twentieth Century ◽  
Problem Solving ◽  
Social Intelligence ◽  
Brain Size ◽  
Social Brain ◽  
Social Intelligence Hypothesis ◽  
The Social ◽  
Intellectual Abilities ◽  
Main Driver ◽  
Machiavellian Intelligence

The first discussion of a relationship between sociality and intelligence came in the middle of the twentieth century, especially by Humphrey who suggested that living socially demanded intellectual abilities above and beyond those required by an animal’s ecology. This led to the Social Intelligence Hypothesis, and then the Machiavellian Intelligence Hypothesis, both proposing that sociality was the main driver of the superior intellect of primates, especially humans. Two key challenges for this hypothesis are that sociality is difficult to quantify and cognition is not well tested by problem solving. More importantly, as data from more species have been examined, the analyses increasingly fail to show that sociality explains variation in brain size, even in primates. I conclude that appealing as this hypothesis is, it does not do a very compelling job of explaining variation in brain size.

Theory of mind in autism, schizophrenia, and in-between

2008 ◽  
Vol 31 (3) ◽  
pp. 261-262 ◽  
Author(s):  
Ahmad Abu-Akel
Keyword(s):  
Theory Of Mind ◽  
Human Cognition ◽  
Brain Disorders ◽  
Social Brain ◽  
The Social ◽  
And Performance ◽  
Cognition Impairment

AbstractAutism and schizophrenia are presented as the extremes of disorders affecting the social brain. By viewing human cognition impairment in terms of competence and performance, a variety of social brain disorders can be identified along the autistic-psychotic continuum.

scholarly journals Understanding primate brain evolution

2007 ◽  
Vol 362 (1480) ◽  
pp. 649-658 ◽  
Author(s):  
R.I.M Dunbar ◽  
Susanne Shultz
Keyword(s):  
Life History ◽  
Path Analysis ◽  
Group Size ◽  
Brain Size ◽  
Brain Evolution ◽  
Primate Brain ◽  
The Social ◽  
Large Brain ◽  
Brain Data ◽  
The Relationship

We present a detailed reanalysis of the comparative brain data for primates, and develop a model using path analysis that seeks to present the coevolution of primate brain (neocortex) and sociality within a broader ecological and life-history framework. We show that body size, basal metabolic rate and life history act as constraints on brain evolution and through this influence the coevolution of neocortex size and group size. However, they do not determine either of these variables, which appear to be locked in a tight coevolutionary system. We show that, within primates, this relationship is specific to the neocortex. Nonetheless, there are important constraints on brain evolution; we use path analysis to show that, in order to evolve a large neocortex, a species must first evolve a large brain to support that neocortex and this in turn requires adjustments in diet (to provide the energy needed) and life history (to allow sufficient time both for brain growth and for ‘software’ programming). We review a wider literature demonstrating a tight coevolutionary relationship between brain size and sociality in a range of mammalian taxa, but emphasize that the social brain hypothesis is not about the relationship between brain/neocortex size and group size per se ; rather, it is about social complexity and we adduce evidence to support this. Finally, we consider the wider issue of how mammalian (and primate) brains evolve in order to localize the social effects.

scholarly journals Coevolution of cultural intelligence, extended life history, sociality, and brain size in primates

2017 ◽  
Vol 114 (30) ◽  
pp. 7908-7914 ◽  
Author(s):  
Sally E. Street ◽  
Ana F. Navarrete ◽  
Simon M. Reader ◽  
Kevin N. Laland
Keyword(s):  
Life History ◽  
Social Learning ◽  
Group Size ◽  
Social Group ◽  
Brain Volume ◽  
Brain Size ◽  
Research Effort ◽  
Human Cognition ◽  
Primate Species ◽  
Brain Expansion

Explanations for primate brain expansion and the evolution of human cognition and culture remain contentious despite extensive research. While multiple comparative analyses have investigated variation in brain size across primate species, very few have addressed why primates vary in how much they use social learning. Here, we evaluate the hypothesis that the enhanced reliance on socially transmitted behavior observed in some primates has coevolved with enlarged brains, complex sociality, and extended lifespans. Using recently developed phylogenetic comparative methods we show that, across primate species, a measure of social learning proclivity increases with absolute and relative brain volume, longevity (specifically reproductive lifespan), and social group size, correcting for research effort. We also confirm relationships of absolute and relative brain volume with longevity (both juvenile period and reproductive lifespan) and social group size, although longevity is generally the stronger predictor. Relationships between social learning, brain volume, and longevity remain when controlling for maternal investment and are therefore not simply explained as a by-product of the generally slower life history expected for larger brained species. Our findings suggest that both brain expansion and high reliance on culturally transmitted behavior coevolved with sociality and extended lifespan in primates. This coevolution is consistent with the hypothesis that the evolution of large brains, sociality, and long lifespans has promoted reliance on culture, with reliance on culture in turn driving further increases in brain volume, cognitive abilities, and lifespans in some primate lineages.

scholarly journals Why Humans Aren’t Just Great Apes

2008 ◽  
Vol 3 (3) ◽  
pp. 15-33 ◽  
Author(s):  
Robin I.M. Dunbar
Keyword(s):  
Great Apes ◽  
Story Telling ◽  
Social Brain ◽  
The Past ◽  
Natural Development ◽  
The Social ◽  
The World ◽  
Primate Sociality

Although we share many aspects of our behaviour and biology with our primate cousins, humans are, nonetheless, different in one crucial respect: our capacity to live in the world of the imagination. This is reflected in two core aspects of our behaviour that are in many ways archetypal of what it is to be human: religion and story-telling. I shall show how these remarkable traits seem to have arisen as a natural development of the social brain hypothesis, and the underlying nature of primate sociality and cognition, as human societies have been forced to expand in size during the course of our evolution over the past 5 million years.

scholarly journals When Individuals Do Not Stop at the Skin

2010 ◽  
Author(s):  
Alan Barnard
Keyword(s):  
Social Networks ◽  
Group Size ◽  
Collective Consciousness ◽  
Social Brain ◽  
Evolution Of Language ◽  
Hunter Gatherers ◽  
Theoretical Concepts ◽  
The Social ◽  
Three Phases

This chapter examines contemporary hunter-gatherer societies in Africa and elsewhere in light of the social brain and the distributed mind hypotheses. One question asked is whether African hunter-gatherers offer the best model for societies at the dawn of symbolic culture, or whether societies elsewhere offer better models. The chapter argues for the former. Theoretical concepts touched on include sharing and exchange, universal kin classification, and the relation between group size and social networks. The chapter offers reinterpretations of classic anthropological notions such as Wissler's age-area hypothesis, Durkheim's collective consciousness and Lévi-Strauss's elementary structures of kinship. Finally, the chapter outlines a theory of the co-evolution of language and kinship through three phases (signifying, syntactic and symbolic) and the subsequent breakdown of the principles of the symbolic phase across much of the globe in Neolithic times.

scholarly journals Absolute, not relative brain size correlates with sociality in ground squirrels

2016 ◽  
Vol 283 (1827) ◽  
pp. 20152725 ◽  
Author(s):  
Jan Matějů ◽  
Lukáš Kratochvíl ◽  
Zuzana Pavelková ◽  
Věra Pavelková Řičánková ◽  
Vladimír Vohralík ◽  
...  
Keyword(s):  
Body Mass ◽  
Life History Traits ◽  
Brain Size ◽  
Empirical Support ◽  
Ground Squirrels ◽  
Single Family ◽  
Social Brain ◽  
The Social ◽  
Tightly Coupled ◽  
Relative Brain Size

The social brain hypothesis (SBH) contends that cognitive demands associated with living in cohesive social groups favour the evolution of large brains. Although the correlation between relative brain size and sociality reported in various groups of birds and mammals provides broad empirical support for this hypothesis, it has never been tested in rodents, the largest mammalian order. Here, we test the predictions of the SBH in the ground squirrels from the tribe Marmotini. These rodents exhibit levels of sociality ranging from solitary and single-family female kin groups to egalitarian polygynous harems but feature similar ecologies and life-history traits. We found little support for the association between increase in sociality and increase in relative brain size. Thus, sociality does not drive the evolution of encephalization in this group of rodents, a finding inconsistent with the SBH. However, body mass and absolute brain size increase with sociality. These findings suggest that increased social complexity in the ground squirrels goes hand in hand with larger body mass and brain size, which are tightly coupled to each other.

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