General Directives of The Family Unit Humans are “genetically disposed to form families that display several common features”, including: 1.Greater parental investment by women than men 2.Differential investment in offspring based on projected reproductive potential 3.Tendency for women to marry men with the greatest resources

Societal Conditioning of Offspring One parental responsibility is to socially and morally condition offspring for maximum success in society Different societies have different social and moral codes. Ex: – Western culture: get a good job, buy a house on a cul-de-sac, join local country club, etc – Yanomamo tribe of Brazil: kill rival tribesman = get laid vs

Parental Investment Conflict Inter-family conflict is common, despite it being true that acting altruistically towards one another is in the best interest Parents with one offspring direct 100% of their resources towards it When another offspring is born, resources are shifted towards the newborn From the view of the first offspring, this is NOT beneficial

Parental Investment Conflict cont. Given that siblings have a relatedness coefficient of 0.5, it will benefit the first born child to have the mother invest in it until the point when the benefit to the new sibling is twice the cost to herself Conflict arises when the firstborn attempts to divert parental resources to itself – This often materializes in the form of temper-tantrums

Reproductive Suppression For a mother having one offspring of childbearing age, genetic cost-benefit analysis concludes that inclusive fitness is maximized by the mother having another child, NOT by the offspring having a child

Reproductive Suppression cont. Benefits: 1.Inclusive fitness is maximized 2.Best utilization of limited resources Note: In this case it is the fitness of the MOTHERS genes that are maximized – Coefficient of relatedness for child: 0.5 (1 vs 2 and 1 vs 3) – Coefficient of relatedness for grandchildren: 0.25 (1 vs 4) This is true until the mother is no longer of childbearing age. At this point, genetic utility will be maximized by having grandchildren

In Summary The family unit is genetically predispositioned to have several general traits One role of parents is to ensure their offspring fit well into the social framework of their society Conflict in the family can arise from siblings competing for parental resources It is genetic benefit is immediately maximized by mothers having more children, NOT by having grandchildren

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