To what degree does increasing life span tend to favor further increases in life span due to an enhanced effect of cooperative, altruistic behavior? Can this create runaway extension of life span in species with greater levels of such behavior? Our own species is the example in mind when asking these questions, as illustrated by the Grandmother hypothesis as an explanation for the exceptional longevity of humans in comparison to other primate species. Our intelligence makes us better at cooperation, which allows natural selection to operate at ever older ages, because individuals in later life contribute to the success of their descendants.
Equally, we can ask whether longevity is necessary for cooperative, altruistic behavior to be selected. If species are too short-lived perhaps there is less selection pressure for the emergence of cooperative behaviors. The authors of this paper mount the argument that species without long periods of overlapping shared experience will tend to be less likely to evolve altruism, but – inconveniently – this doesn’t appear in nature in any long-lived species. This makes it hard to argue any of the points in this paper on the basis of evidence rather than model-based speculation.
Many primate species