Discrete hierarchical organization of social group sizes

By Wei‐Xing Zhou, Didier Sornette, R. A. Hill, Robin I. M. Dunbar. Proceedings of the Royal Society of London. Biological Sciences, 2004

530 citations recorded by the source corpus.

The ‘social brain hypothesis’ for the evolution of large brains in primates has led to evidence for the coevolution of neocortical size and social group sizes, suggesting that there is a cognitive constraint on group size that depends, in some way, on the volume of neural material available for processing and synthesizing information on social relationships. More recently, work on both human and non–human primates has suggested that social groups are often hierarchically structured. We combine data on human grouping patterns in a comprehensive and systematic study. Using fractal analysis, we identify, with high statistical confidence, a discrete hierarchy of group sizes with a preferred scaling ratio close to three: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3–5, 9–15, 30–45, etc. Such discrete scale invariance could be related to that identified in signatures of herding behaviour in financial markets and might reflect a hierarchical processing of social nearness by human brains.

Subfields: Ecology, Evolution, Behavior and Systematics, Social Psychology, Sociology and Political Science

View Paper: https://www.semanticscholar.org/paper/38b1f195756a8347924b6ed5fed299f579d9a958

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Citations in the corpus

From opportunistic networks to opportunistic computing (2010, background): “In more detail, experimental evidence from real measurements presented in [ 17 ] (and confirmed by several other studies) highlights at least four well-identified shells.”
The “online brain”: how the Internet may be changing our cognition (2019, background): “…ticularly females) spent more time on social media and smartphones have a greater prevalence of mental health problems, including depression, than those who spent more time on “nonscreen” activities 116 , with greater than 5 hrs/day (versus 1 hr/day) associated with 66% increased risk of one…”
Activity Spaces, Biographies, Social Networks and their Welfare Gains and Externalities: Some Hypotheses and Empirical Results (2005, result): “It is also consistent with the group size scaling laws proposed in Zhou et al. (2005).”
The burden of proof for a cultural group selection account (2014, background): “Even in contexts where no common culture exists, individuals develop social ties (Zhou et al. 2005) that make cooperation possible, such as trust relationships.”
Perspective-taking and memory capacity predict social network size (2007, background): “In a recent analysis, Zhou et al. (2003) were able to show that these various grouping levels form a hierarchically clustered sequence with a consistent scaling ratio of 3.”
Do online social media cut through the constraints that limit the size of offline social networks? (2016, background): “An important feature of natural social networks in both humans [19,20,25] and non-human primates [31] is that they are structured into a distinctive series of hierarchically inclusive layers that have a natural scaling ratio of approximately 3.”
Clarifications to questions and criticisms on the Johansen–Ledoit–Sornette financial bubble model (2011, methodology): “It is worthwhile to mention that there are other procedures implemented systematically in the more recent Refs.”
Ventromedial prefrontal volume predicts understanding of others and social network size (2011, background): “Personal social networks consist of a series of concentric layers that include progressively more individuals, with the size of the layers scaling with each other with a constant scaling ratio of about 3 (Hill & Dunbar 2003; Zhou et al. 2005; Hamilton et al. 2007).”
Safebook: A privacy-preserving online social network leveraging on real-life trust (2009, background): “As the strength of a relation is not the same for all links [7], in Safebook each user associates a particular trust level to each of”
Mind the gap; or why humans are not just great apes (2008, background): “These circles of acquaintanceship seem to have a very consistent structure: each annulus includes about twice as many people as the one immediately inside it, so that the cumulative numbers of individuals included in successive circles exhibit a constant scaling ratio of approximately 3 (Zhou et al.”
Exploring variation in active network size: Constraints and ego characteristics (2009, background): “…of intimacy and level of interaction between ego and alter decreases (Hill and Dunbar, 2003; Mok et al., 2007) suggests that there are constraints on the number of relationships ego can maintain at a given level of intensity (Zhou et al., 2005; Roberts, 2009; see also Bernard and Killworth, 1973).”
Twitter as Data (2018, background): “maintain, however, exist in approximately three groups of increasing intimacy (Zhou et al., 2005).”