"Why we live in hierarchies: a quantitative treatise" https://arxiv.org/abs/1707.01744 https://arxiv.org/abs/1707.01744 might be a relevant read (Dunbar's Numbe

"Why we live in hierarchies: a quantitative treatise" https://arxiv.org/abs/1707.01744 https://arxiv.org/abs/1707.01744 might be a relevant read (Dunbar's Number does come up)