SYNOPSIS
Kin Selection: This hypothesis argues that all individuals of species serve only to propagate their own genes and compete with those of all others proportionally to the degree that those genes differ. This is prescribed by the role of reproduction in preserving the same genes in close relatives including collateral ones, such as uncles or cousins, while more distant relatives are treated as competitors. It appears superficially to be a pure expression of Darwinian evolution. It is ingenious, but that is about all that can be said for it. Darwin himself never made such a proposal and indeed gave great emphasis to the role of emotions in guiding animal and human behavior. Although kin selection has become a dogma, experience gained over the last half century has failed to find support for it either intuitively or through observation. Group Selection: This hypothesis proposes that genes adapt to the group of social species rather than to each individual. Certainly, mutations that are favorable to multiple animals can diffuse throughout the herd by promoting cooperation. However, the limitation of this interpretation is that it does not explain how the genes cause this action and therefore does not advance our understanding of sociality in the real world. Emotions: It has become customary in some circles to evaluate animal actions as being precisely directed towards favorable outcomes, but that is not how nature works. Their and our brains are instead guided towards anticipated or realized pleasurable feelings and away from aversive or painful ones. These are expressed as emotional signals which are controlled by hormones. Sociality itself is no more complicated than a pleasurable sensation of the presence of other familiar animals nearby, which may extend to close or distant relatives as well as unrelated individuals and is evidenced by the formation of herds. Hormones: The two hormones that control sociality in mammals and birds are testosterone and estradiol. These are well recognized for contributing to the attraction of opposite genders, but their decline or absence causes them to reward proximity to the same sex. So these sex hormones account for competitive reproduction during the mating season and for collegiality in the rest of the year. The latter property is essential for animals to collaborate and undertake tasks that would otherwise be beyond their reach. The evidence that sociality correlates inversely with the output of androgens or estrogens is very strong since it is precisely observed in many different species of mammal or bird, many types of association and in both genders. Human Sociality: A special case is that of species such as humans who breed at any time during the year, because both their sexual and social qualities need to be expressed simultaneously. Sexual orientation develops initially in the maturing brains of embryos. There is good evidence that individuals of either gender may elicit reverse sexuality at this stage which leads to homosexuality. It is very likely that individuals of each gender exhibit their own biased continuum of sexual orientation. In this way, both sexuality and sociality may coexist in all individuals at different levels which benefits the whole population and is the essential component of human civilization. Read the full article












