From the gene's point of view, evolutionary success ultimately depends on leaving behind the maximum number of copies of itself in the population. A gene can also increase its evolutionary success by promoting the reproduction and survival of these related or otherwise similar individuals. This leads natural selection to favor organisms that would behave in ways that maximize their inclusive fitness. It is also true that natural selection favors behavior that maximizes personal fitness. There is substantial evidence that humans act generally more altruistically to close genetic kin compared to genetic non-kin