In very risky environments, altruists are favored by natural selection

Sorin Solomon

Hebrew University of Jerusalem, Racah Institute of Physicsh, Jerusalem, Israel

Altruism elicits in humans very powerful and diverse feelings. Its paradoxical nature makes it mysterious and challenging to understand.

It is difficult to understand why a rational being would sacrifice its own interests for somebody else especially if one's reproduction fitness depends on them. It is also difficult to believe that such a treat would survive natural selection. In fact it was shown by rigorous theorems in a wide range of conditions that the Nash stable strategy is to be selfish and not to share.

We show that the resources sharing phenotype is highly favored and wins natural selection dramatically if instead of incurring fixed gains and losses, the players gain or loose randomly fixed fractions of their current resources.

Thus the solution of the sharing paradox resides in recognizing the random multiplicative (rather then the usual game-theory "additive") character of the real life, society, economic and cultural "games".

In this talk I will present analytical and numerical results for different variations of the model along with results from intensive computer simulations that support and clarify these results.