Evolutionary psychology of kin selection and family

Kin selection is a crucial aspect to Evolutionary Psychology, and the understanding of concepts such as Altruism, Inclusive Fitness, and Hamilton’s Rule. Kin selection is the process of natural selection between kin or nonkin, evaluating the genetic possibilities and values of another organism. Kin selection is seen as a social behavior and is a cost/benefit relationship: the animal that sacrifices something for kin experiences the cost while the receiving kin benefits. This selection often occurs between parent and offspring relationships, but can extend further creating the idea of altruism within species. Species are more apt to showing altruism to their blood relatives versus species that are less related to them. Chapais, Savard, and Gauthier show in their study the many factors responsible for determining group living. Evolutionary Psychologists examine which psychological traits are evolved adaptations from the EEA (Environment of Evolutionary Adaptedness). Therefore it is beneficiary to look at physiological mechanisms in a functional manner. The mind is thought to have a modular structure similar to the body, with different adaptations serving different functions. Therefore, kin selection serves an important purpose in the adapted brain because it favors actions that support genetic relatives. Using Hamilton's rule to determine how group-living individuals should allocate altruism among their various categories of kin has proven extremely difficult.
Hamilton's Rule
W. D. Hamilton introduced Inclusive Fitness, referring to the fitness that includes contributions from kin, and individuals sharing genes.
Parental care of offspring is an altruistic behavior directed to related individuals because they share 50% of genes. This displays the idea that people would cooperate with close kin, for example siblings, before cousins or people who are not related to the individual. This idea also includes the cost and benefit consideration of evolution.
The evolutionary principle of kin selection depicts why it is adaptive for animals to differentiate kin from non-kin. This idea is present in the idea of unrelated young with the example of stepchildren, a common family structure in today’s society. In Archers study of violence it was found that there is a higher rate of violence between families without genetic relations, likely because of the kin relation and altruism effect. From the gene's point of view, evolutionary success ultimately depends on leaving behind the maximum number of copies of itself in the population. In 1964 W. D. Hamilton proved mathematically that, because close relatives of an organism share some identical genes, a gene can also increase its evolutionary success by promoting the reproduction and survival of these related or otherwise similar individuals. Hamilton claimed that this leads natural selection to favor organisms that would behave in ways that maximize their inclusive and personal fitness.
*Hamilton's rule describes mathematically whether or not a gene for altruistic behavior will spread in a population:
<code>rB > C</code>
where
:r = the genetic relatedness of the recipient to the actor, often defined as the probability that a gene picked randomly from each at the same locus is identical by descent.
:B = the additional reproductive benefit gained by the recipient of the altruistic act,
:C = the reproductive cost to the individual performing the act.
With Hamilton's Rule in mind, why would the Foster Care system work? If caretakers are taking in non-kin and treating them as their own, would the genetic relatedness factor still apply? Timmer addresses this in her article by analyzing the social exchange theory. Timmer argues that the perceived costs and benefits of parenting foster children influence the parental investment in the children. Analyses showed that nonkin caregivers rated their foster children's behavior problems as significantly more severe than kin caregivers, but rated themselves as significantly less stressed. The authors discuss the implications of these findings for foster children's placement stability and long-term success of both children and foster parents.
Altruism
A behaviour that increases the direct fitness of the actor is mutually beneficial if the recipient also benefits, and selfish if the recipient suffers a loss. A behaviour that reduces the fitness of the actor is altruistic if the recipient benefits, and spiteful if the recipient suffers a loss. This classification was first proposed by Hamilton in 1964. Altruism is a puzzle in biology and the social sciences because an individual behaves in ways to benefit another even though it comes at a cost to the individual performing the altruistic action. This was originally solved by Hamilton, as mentioned above, because kinship patterns are not necessarily built on blood ties.
*A fundamental principle of natural selection also applies to synthetic organisms when these have heritable properties. This was shown through conducted simulations of foraging robots. The costs and benefits of altruism were manipulated to see the conditions under which altruism evolves suggests that genes and culture co-evolved together to allow social patterns to develop including altruism and selfishness.
Stewart- William's research suggests that, due to evolutionary principles, there will be differences in the nature of altruism directed toward kin vs. non-kin. Consistent with an evolutionary analysis, his study showed that as the cost of helping increases, kin receive a larger share of the help given (from the altruist), whereas nonkin received a smaller share. For low-cost help, people helped friends more than they helped siblings; for medium-cost help, they helped siblings and friends equally; and for high-cost help, they expressed a greater willingness to help siblings in comparison to friends. This shows how even though people are more willing to assist direct blood lines rather than acquaintances in varying degrees of cost, help is given to non-relatives when the costs to the altruist are low.

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