PSY 375 final exam
life history perspective - ANS-- life history/parental care adaptations evolve to produce
the optimal number of offspring that could survive or compete socially, not the maximum
number of offspring
- turtles: slow life history but don't really invest in the baby
adaptations - ANS-onset of menstruation in women, frequency of twinning (Lemurs)
mothers in better conditions (more body fat) are more likely to have _______ - ANS--
twins
- though tradeoffs are made, human twins faced heightened risks for many medical
problems
women spend ____ to ____ times more than men in infant care - ANS-10 to 20 times
overall, the impact of the father is _______, but the mother's impact is still _______
(when it comes to investing in the baby) - ANS-large; larger
Trivers' theory of parental investment
(why do mothers do more?) - ANS-- there are sex differences in initial investment
(sperm v. egg) therefore there will be differences in the operational sex ratio (the ratio of
males and females that are interested in mating)
- once there is an unequal OSR, there will be differences in mating competition/mate
choice
contexts affecting investment - ANS-- natural selection favors the evolution of
mechanisms in parents that favor offspring who are likely to have a higher reproductive
return on investment
3 contexts affecting investment - ANS-1) genetic relatedness to offspring
2) ability of offspring to convert parental care into fitness
3) alternative use of resources (should i invest in this kid or invest in future kids, nieces,
or focus on more mating opportunities)
ability to transform parental investment into RS - ANS-- if a child is badly malformed/sick
it's unlikely they will be able to have good RS (parents may have evolved tendencies to
not invest in such children)
, - if a child is healthy it will make sense to invest in them heavily
- one unit of parental effort expended on the 2nd fittest child could have greater payoff
to parent' RS than their investment in their most fit child
Platek et al (2002)
[genetic relatedness] - ANS-- asked men how much they would invest in different
children after viewing each child's face
- the men had previously had their picture taken and the experimenter's partially
morphed some of the child's faces to slightly resemble the men
- results: the men generally indicated they would invest more in the children that looked
more like themselves although they had no knowledge of the self-resemblance
Daly & Wilson (1982)
[genetic relatedness] - ANS-- reviewed videotapes of pos-birth scenes and documented
utterances about who the baby was said to resemble
- 80% of the time remarks were made about the baby's resemblance to their father
- they also sent out surveys about who new babies seemed to resemble and found
similar results: mothers 80% and mothers' 66% said the baby was similar to the putative
father
Beaulieu & Bugental (2008)
[ability to transform parental investment into RS] - ANS-- examined how much 60 moms
invested in low-risk babies (typical) and high-risk babies (premature)
- mothers with low resources showed greater investment in low-risk than high-risk
babies & mothers with higher resources showed greater investment in high-risk than
low-risk babies
- this indicates that evolved mechanism interact with environmental input
Daly & Wilson (1988)
[alternative uses of parental investment] - ANS-- Canadian women would commit
infanticide more frequently when they were young
- evolutionary logic: younger women may not wish to be parents yet if they anticipate
being in a better position in the future and for older women its "now or never"
- also predicted: infanticide would occur more among unmarried women than married
women, this was true at almost every age; logic = women will prefer to delay having
children until they are married
Trivers's theory of parent-offspring conflict (1971) - ANS-the genetic interests of parents
and their offspring are generally in alignment (ex: the mother wants the chicks to survive
and so do the chicks)
life history perspective - ANS-- life history/parental care adaptations evolve to produce
the optimal number of offspring that could survive or compete socially, not the maximum
number of offspring
- turtles: slow life history but don't really invest in the baby
adaptations - ANS-onset of menstruation in women, frequency of twinning (Lemurs)
mothers in better conditions (more body fat) are more likely to have _______ - ANS--
twins
- though tradeoffs are made, human twins faced heightened risks for many medical
problems
women spend ____ to ____ times more than men in infant care - ANS-10 to 20 times
overall, the impact of the father is _______, but the mother's impact is still _______
(when it comes to investing in the baby) - ANS-large; larger
Trivers' theory of parental investment
(why do mothers do more?) - ANS-- there are sex differences in initial investment
(sperm v. egg) therefore there will be differences in the operational sex ratio (the ratio of
males and females that are interested in mating)
- once there is an unequal OSR, there will be differences in mating competition/mate
choice
contexts affecting investment - ANS-- natural selection favors the evolution of
mechanisms in parents that favor offspring who are likely to have a higher reproductive
return on investment
3 contexts affecting investment - ANS-1) genetic relatedness to offspring
2) ability of offspring to convert parental care into fitness
3) alternative use of resources (should i invest in this kid or invest in future kids, nieces,
or focus on more mating opportunities)
ability to transform parental investment into RS - ANS-- if a child is badly malformed/sick
it's unlikely they will be able to have good RS (parents may have evolved tendencies to
not invest in such children)
, - if a child is healthy it will make sense to invest in them heavily
- one unit of parental effort expended on the 2nd fittest child could have greater payoff
to parent' RS than their investment in their most fit child
Platek et al (2002)
[genetic relatedness] - ANS-- asked men how much they would invest in different
children after viewing each child's face
- the men had previously had their picture taken and the experimenter's partially
morphed some of the child's faces to slightly resemble the men
- results: the men generally indicated they would invest more in the children that looked
more like themselves although they had no knowledge of the self-resemblance
Daly & Wilson (1982)
[genetic relatedness] - ANS-- reviewed videotapes of pos-birth scenes and documented
utterances about who the baby was said to resemble
- 80% of the time remarks were made about the baby's resemblance to their father
- they also sent out surveys about who new babies seemed to resemble and found
similar results: mothers 80% and mothers' 66% said the baby was similar to the putative
father
Beaulieu & Bugental (2008)
[ability to transform parental investment into RS] - ANS-- examined how much 60 moms
invested in low-risk babies (typical) and high-risk babies (premature)
- mothers with low resources showed greater investment in low-risk than high-risk
babies & mothers with higher resources showed greater investment in high-risk than
low-risk babies
- this indicates that evolved mechanism interact with environmental input
Daly & Wilson (1988)
[alternative uses of parental investment] - ANS-- Canadian women would commit
infanticide more frequently when they were young
- evolutionary logic: younger women may not wish to be parents yet if they anticipate
being in a better position in the future and for older women its "now or never"
- also predicted: infanticide would occur more among unmarried women than married
women, this was true at almost every age; logic = women will prefer to delay having
children until they are married
Trivers's theory of parent-offspring conflict (1971) - ANS-the genetic interests of parents
and their offspring are generally in alignment (ex: the mother wants the chicks to survive
and so do the chicks)
