The previous chapters indicated that human sharing goes beyond the primate heritage. Evolutionary pressures can neither explain why sharing is so pronounced and wide among humans, nor the various forms in which it takes place. Rather, human sharing is in itself a complex phenomenon, more complex than usually imagined by those who are not participating in the economy of sharing on a daily basis. From the point of view of behavioural ecology, sharing is all about strategic individual decisions about how to allocate things. In Gurven’s view (2004: 543) this is what modelling sharing is all about:

Imagine a male forager with a fresh kill, or a female forager with a basket of fruits or roots. Each must decide (or have decided for them): (1) How much to give to others (depth); (2) How many families should receive a share (breadth), and (3) How much should be given to each of n other locally available individuals (equality)? Each model […] predict[s] when sharing should occur. These differ in the kinds of benefits returned to donors, and the manner in which these benefits are paid.