Parental Investment Flashcards
What is the definition of parental investment?
Any investment by a parent in an offspring that increases the chance that the offspring will survive.
In humans which sex invests more and give examples of what they invest?
- The woman invests more than the man in each offspring.
- FATHER: sperm.
- MOTHER: 9 months carrying, breast feeding, egg
How might the different investment leves affect the parents ability to invest in futher offspring?
When mother is preganant she cannot invest in having more children whereas the male can. Parents do not invest alturistically but rather to invcrease the chances of passing on their genes.
What differences in gametes may explain differences i parental investment.
- female gametes are far less numerous and more costly to produce than sperm so women have to be careful what happens to them.
- In terms of mate selection, therefore, males go for quantity whilst females go for quality.
- Because of this, women tend to invest more in their offspring whilst men tend to invest more in trying to attract a mate.
Why do women not tend to mate randomly?
- because the risk of getting pregnant without a commited male to protect and provide is too great.
- A high level of post-natal ivestment (eg breastfeeding) from the mother is required so they need to ensire they choose the best man possible.
Why are men often keen to invest less in their offspring?
Becasue of the risk of investing in someone elses genes. Whilst a woman can be 100% sure the baby is theirs, a man always runs a chance of being cuckolded.
However, why might men invest a lot of resources in their offspring?
They want to ensure that the infant survives and this is especially true if they are certain that the child is theirs.
What did Buss find relating to sex differences in parental investment (note: different study to sexual selection one!)
- American students
- Males more concerned about a parteners sexual infidelity whilst females are more concerned about emotional infidelity.
- Supports PI as women are more concerned that a nam will invest time and money in another woman whilst men are worried that they may be cuckolded.
- These findings were supported by brain scans which showed strong physiological responces - scientific credebility
- However, only students used who are unlikely to have the same barriers as older people in long term relationships.
What did Marlowe et al find?
- As paternal resembelance and certainty of mate fidelity increased for men, so did the reported paternal investment.
- Supports PI as men do not want to risk investing in a child that isn’t theirs.
- However, third variables such as quality of relationship with mother.
Give details of three situations that PI can explain.
- mor single mums than dads as female makes greater investement so more likeluy to be let with baby.
- Historically more sperm donors than egg donors as sperm is unlimited but finite number of eggs.
- Noe law change so cannot give soerm anonymously so kids can trace biological fathers, Guys scared they will be foreced to inest.
Why is this their socially sensitive?
Evolutionary idea suggests men are promiscuous and unreliabe whiulst women are gold-digging. Also implies that investment is selfish and merely about securing survival of genes.
What can the theory not explain?
- Farthers for Justice
- adoption
- step parents investing
- vasectomy
List three typical critiscisms of evolutionary theories like PI.
- REDUCTIONIST: gene survival is only explanation of parental investment. Humanistic? Copying parents? Pass on beliefs? Investment is rewarding?
- CANNOT FALSITY: No way to test adaptions caused by eviolution thousands of hyears ago - lacks scientific credebility.
- DETERMINISTIC: our genes dictate how and when we will invest and ignored our free will. Surely humans have control over their actions and can choose whether or not to invest?
