HC 5 Flashcards
Why Do Mothers Provide More Parental Care Than Fathers?
- Paternity Uncertainty Hypothesis
- Mating Opportunity Cost Hypothesis
• Paternity Uncertainty Hypothesis – Females are 100 percent sure of genetic relatedness of offspring – Males are never sure: • There is always some probability that another male has fertilized the female’s egg
• Mating Opportunity Cost Hypothesis
– Missed additional matings as a direct result of effort devoted to offspring
– Sex ratio as moderator (e.g., China)
Parental Favoritism
– Investment in offspring should favor some offspring over others
– Selection will favor investment in offspring who are likely to provide higher reproductive return
• Genetic relatedness of the offspring
• Ability of offspring to convert parental care into fitness
Genetic Relatedness of Offspring
Parental love and resources are substantially less likely to be directed toward children that are not biologically related
A man has at least two sources of information to consider the likelihood that he is the genetic father of a given child:
– Information about his partner’s sexual fidelity during the period in which she conceived
– Perceptions of the child’s resemblance to him (Daly & Wilson,1988)
Genetic Relatedness of Offspring
– Three predictions:
- Men will allocate more resources to their genetic children than to their stepchildren
- Men who are uncertain about whether children are genetically their own will invest less than men who are certain the children are their own
- Men will invest more in children when the child’s mother is their current mate than they will in children from former mateships
Who Are Newborn Babies Said to Resemble?
When the baby was said to resemble either parent, the mother’s remarks about the resemblance to the father were four times as frequent (80 percent) as her remarks about the baby’s resemblance to her (20 percent)
Facial resemblances impact in fathers and mothers?
- Fathers of children whose faces resembled their own reported being much more “emotionally close” to them compared to those lacking resemblance
- In contrast, mother’s facial resemblance to the child was unrelated to how emotionally close they felt
Offspring’s Ability to Convert Parental Care into Reproductive Success
> reaction mother on how healthy the child is (3)
- The health status of the child would affect the degree of positive maternal behavior
- When the infants were four months old, roughly half the mothers directed more positive maternal behavior toward the healthier infants
- By the time the infants were eight months old, however, every single one of the mothers directed more positive maternal behavior toward the healthier infant
The Trivers-Willard Hypothesis
Investment in Sons versus Daughters: The Trivers-Willard Hypothesis
– Parents will produce more sons and invest more in sons when the parents are in good condition and hence have a chance of producing a son who will be highly successful in the mating game (Trivers & Willard, 1973)
– Conversely, if the parents either are in poor condition or have few resources to invest, then they should invest more in daughters
The Theory of Parent
–Offspring Conflict
Parents would want to allocate equal resources among her children, but each child would want more for him or herself Conflicts over: – Weaning – Investment in other siblings – Helping parents
Parent’s (hidden) agenda for you
• Attractiveness of partner is more important for you than your parents
Parents protect their reproductive interests:
• Socialize children in gender roles
• Build alliances with other families through the marriage of their children
• Boost their social status
• Not bring shame to the family
• Maintain connections (important for grand parenting)
• Receive care in old age
Family Conflicts
• Sibling Conflict
• Parent-Offspring Conflict
• Mother-Father Conflict
• Sibling Conflict – Compete with each other for access to parental resources • Parent-Offspring Conflict – Parents attempt to invest “equally” – Children desire more for themselves • Mother-Father Conflict – Conflict over how much to invest to offspring within the family
Inclusive Fitness
The effects of an individual’s actions on the reproductive success of genetic relatives weighted by the degree of genetic relatedness
Explain Altruistic Behavior
Altruism could evolve if the cost to self was outweighed by benefit to recipient multiplied by the probability that the recipient carried a copy of genes
Hamilton’s Rule
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