The Dawn of Everything: A New History of Humanity

by David Graeber

The most basic social unit is the pair-bonded family, with shared investment in offspring. To provide for themselves and dependants, these nuclear units are obliged (or so the argument goes) to cluster together in ‘bands’ made up of five or six closely related families. On ritual occasions, or when game is particularly abundant, such bands coalesce to form ‘residential groups’ (or ‘clans’) of roughly 150 persons, which – according to Dunbar – is also around the upper limit of stable, trusting relationships we are cognitively able to keep track of in our heads. And this, he suggests, is no coincidence. Beyond 150 (which has come to be known as ‘Dunbar’s Number’) larger groups such as ‘tribes’ may form – but, Dunbar asserts, these larger groups will inevitably lack the solidarity of smaller, kin-based ones, and so conflicts will tend to arise within them.2