The Evolution of Generosity: How Natural Selection Builds Devices for Benefit Delivery

Darwin’s great scientific contribution was to reveal how a blind, mindless, purely physical process can cause the complex functional design we see all around us in the biological world. By introducing the concept of natural selection, Darwin explained how evolution builds devices. Here, we explain how natural selection can build devices whose function is to cause organisms to take actions that boost the welfare of other organisms, which we might call benefit-delivery devices. Benefit-delivery devices come in two broad types: (a) Those that evolve because the genes that assemble them during ontogeny increase the direct reproductive success of the organism in whom those genes reside, and (b) those that evolve because the genes that assemble them during ontogeny increase the reproductive success of exact replicas of those genes that reside in other organisms (most recognizably, in the organism’s genetic relatives). In this paper, we catalogue some of the benefit-delivery devices with which natural selection might have outfitted human beings and illustrate how they seem to work.