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‘Dunbar’s number’ deconstructed

Citation

Lindenfors, Patrik; Wartel, Andreas; Lind, Johan (2021), ‘Dunbar’s number’ deconstructed, Dryad, Dataset, https://doi.org/10.5061/dryad.ghx3ffbnn

Abstract

A widespread and popular belief posits that humans possess a cognitive capacity that is limited to keeping track of and maintaining stable relationships with approximately 150 people. This influential number, ‘Dunbar’s number’, originates from an extrapolation of a regression line describing the relationship between relative neocortex size and group size in primates. Here we test if there is statistical support for this idea. Our analyses on complementary datasets using different methods yield wildly different numbers. Bayesian and GLS phylogenetic methods generate approximations of average group sizes between 70–107 and 0-42, respectively. However, enormous 95% confidence intervals (4–508 and 0–336, respectively) imply that specifying any one number is futile. A cognitive limit on human group size cannot be derived in this manner.

Methods

Data collected from the literature. Sources included in table.

Funding

Knut and Alice Wallenberg Foundation, Award: KAW 2015.005

Knut and Alice Wallenberg Foundation, Award: KAW 2015.005