This questionnaire study sheds light on the psychological component of kin selecting tendencies predicted by Hamilton's (1964b) inclusive fitness theory of discriminatory altruistic behavior based on genetic similarity. Participants rated donations of assistance aiding survival and material wealth as more rational and ethical when these actions were performed for closer relatives. Participants also felt a greater obligation to perform these acts for a close relation. A comparison condition where assistance was unlikely to affect survival or reproductive success did not exhibit these tendencies.
Speculation on altruism reflects on the fundamental character of human nature. Philosophers throughout the ages have debated the question of whether humans actually intend to perform actions that are beneficial to others and costly to themselves, without any clear resolution (Cialdini, Brown, Lewis, Luce & Neuberg, 1997). Social psychologists continue this debate. Although some argue that the experience of empathy for others leads to truly altruistic actions (Batson, Sager, Garst, Kang, Rubchinsky & Dawson, 1997), others believe that conditions leading to empathic concern lead also to a greater sense of self-other overlap (Cialdini et al., 1997). Thus, helping others leads to a more favorable mental state because it is at least partially self-directed.
Helping and altruism may also be approached through the framework of evolutionary theory. Classical (Darwinian) fitness is the probability that individuals will successfully reproduce by passing on their genes to future generations through direct offspring. Members of a species who sacrifice their resources for the benefit of others beyond spouses and offspring would, on average, have fewer successful descendants - thus an inherited tendency for this behavior would not spread through the population. Hamilton's inclusive fitness theory (1964b) expanded the basis of reproductive success to include close relatives who become ancestors of offspring with similar genetic material.
A genetically influenced tendency to favor relatives with assistance is likely to spread across a population when the cost in reproductive fitness to the donor is less than the product of the fitness benefit to the recipients) and the proportion (designated "r") of genes not common to the species that the donor and recipients) share. Identical twins have an r of 1.0, an individual's siblings, parents, and offspring have an r of 0.5, aunts, uncles, nephews, and nieces have an r of .025, first cousins, grandparents and grandchildren have an r of 0.125, etc.
Altruist advocates define altruism as a motivational state with the ultimate goal of increasing another s welfare, (Batson, 1991 p. 6). Hamilton's (1964a) inclusive fitness theory undermines this definition, because genetic self-interest includes someone who shares a high percentage of genetic information. Despite Herbert Spencer's catch phrase survival of the fittest, the ultimate criterion that determines if a genetic tendency for altruism spreads is whether it benefits the genes themselves, not whether it benefits the bearer of the genes (Hamilton, 1964a). Altruist advocates admit that evolutionary theorists have been useful in revealing how self-sacrificial behavior can be consistent with the theory of natural selection; however, they are more concerned with the driving mental motivation of the helper (Batson, 1991). Felt oneness or empathy could arise as a consequence of attachment-related cues that signaled relatively high genetic commonality in the environment of our evolutionary adaptation. An action benefiting genes could be altruistic in terms of the cost to the helping individual.
The existence of kin selecting behaviors, selectively favoring relatives with assistance, is well established in other members of the animal kingdom, but the mental aspects of kin selection are relatively unknown. Some claim that no clear evidence exists for processes enhancing inclusive fitness in humans (e. …