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Unformatted text preview: Problems of Kinship Inclusive fitness theoryimportant in evolutionary psychology Altruismorganism incurs a cost to itself in order to benefit someone else Are there adaptations for providing benefits to others? YES, look at theories! [Inclusive Fitness Theory]William D. Hamilton (1936-2000) Recall the gist of Darwins Theory of Natural Selection: Individuals whose heritable traits are helpful to their own survival [Hamiltons Inclusive Fitness Theory] aka Kin Selection Theory Classical Darwinian Fitness : a traits effect on the Reproductive Success of its bearer Inclusive Fitness (aka: Hamiltons Fitness) : Classical Fitness + a traits effects on the RS of its neighbors E.g. if youre helping your sisters reproductive success, its added to your fitness E.g. if you give a kidney to your sister, it has a larger impact on your inclusive fitness than if you gave it to your first cousin As the degree of genetic relatedness gets lessened, your inclusive fitness is degraded [Hamiltons Rule: rb > c] = Defines how a gene for altruism can spread. r= genetic relatedness between actor and the recipient b= fitness benefit (in terms of the recipients extra offspring production) c= fitness cost (in terms of the actors loss of its own offspring) Altruism can evolve if the fitness benefit to the recipient (b), weighed by its relatedness to an actor (r), outweighs the fitness cost to actor (c). E.g. rb > c Altruism at the individual level is actually selfishness at the gene level. Kin selection includes parental care (special case of altruism towards genetic relatives) as well as altruism towards non-descendant kin. [Theoretical Implications of Hamiltons Rule] Evolved psychological mechanisms for each type of kinship relationship For an adaptation to evolve, it must follow 1) Parenting special case of evolved kinship adaptations 2) Sibship cooperation and competition among siblingsgenetic relatedness of . 50 a. They can compete for access to mates (E.g. two men can become intrasexual rivals for the same woman). So if your brother gets the woman, he is only passing on .25 of your genes! So youre only related to your nephew (.25) but if you succeed in mating with the woman, youre related to your son (.50) so it is to your advantage....
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This note was uploaded on 11/03/2008 for the course PSY 334E taught by Professor Buss during the Spring '08 term at University of Texas at Austin.
- Spring '08
- Evolutionary Psychology