Kinship Without Words

Abstract

This article seeks to identify at what point in hominid evolution language would have become adaptive. It starts by recalling the distinction between kin-selected altruism and reciprocal altruism, noting that the former is characteristic of social insects while the latter is found among some species of social mammal. Reciprocal altruism depends on the exchange of information assuring partners of the other’s continued friendly intent, as in the iterated prisoner’s dilemma. The article focuses on species that practice “fission–fusion”: social behaviour, where the alternation between larger and smaller parties creates greater uncertainty as to individuals’ continued commitment to reciprocity. The greatest uncertainty arises in “atomistic” fission–fusion, where individuals leave and join foraging groups independently. Chimpanzees, bonobos, and human hunter–gatherers practice this type of social behaviour. There is less uncertainty where the smaller social unit is an extended family, as among vampire bats, chacma baboons, and savanna elephants. A comparison of the repertoire of calls and gestures among these species indicates that chimpanzees and bonobos have the largest repertoires. I then point out that, thanks to the higher proportion of meat in the diet, hunter–gatherers must live in far more dispersed communities than chimpanzees or bonobos, yet they practice more complex patterns of cooperation and reciprocity. This, I argue, created a social environment in which language became particularly adaptive. Homo heidelbergensis is identified as the key species in which language could have originated, during the transition between the Lower and Middle Paleolithic.