Chapter 8 Flashcards
(34 cards)
Altruism, as used here, is defined by two conditions:
(1) incurring a cost to the self
(2) provide a benefit to the other person.
evolvability constraint
Only those genes that code for traits that fulfill Hamilton’s rule can spread throughout the population and hence evolve to become part of the species-typical repertoire.
genetic relatedness
the probability of sharing a particular focal gene with another individual over and above the average population frequency of the gene
Another important aspect of kinship is whether a sib is a full or a half sib. Given a common mother, for example, do you and your sibling share a father?
This distinction is theoretically important because full sibs are genetically related by 50 percent on average, whereas half sibs are genetically related by only 25 percent on average. In an intriguing study of ground squirrels, Holmes and Sherman (1982) discovered that full sisters were far more likely than half sisters to cooperate in the mutual defense of their young.
“grandmother hypothesis”
The fact that modern women often live well beyond menopause has led to the hypothesis that menopause
itself evolved as a means of ceasing direct reproduction in order to invest in children and then grandchildren
Daly et al. (1997) outline a set of hypotheses about the universal aspects of the psychology of kinship:
(1) they suggest that ego-centered kin terminology will be
universal.
(2) all kinship systems will make critical distinctions along the lines of sex.
(3) generation is also critical.
(4) kin relationships will be universally arrayed on a dimension of closeness, and closeness will be highly linked with genetic relatedness.
(5) the degree of cooperation and solidarity between kin will be a function of their degree of genetic relatedness.
(6) the elder members of an extended kin family will encourage the younger members to behave more altruistically and cooperatively toward collateral kin.
(7) one’s position within an extended kin network will be core components of the self-concept.
(8) despite differences across cultures in the exact kin terms used, people everywhere will be aware who their “real” relatives are.
(9) kinship terms will be used to persuade and influence other people
The predator confusion hypothesis
The alarm call might function to confuse the predator
by creating a mad scramble, in which all the ground squirrels rush around for safety. This confusion might help the squirrels, including the alarm caller, to escape.
The parental investment hypothesis
Although the alarm caller is placed at greater risk by
sounding the signal, perhaps children are more likely to survive as a result. In this way, the alarm call might function as a form of parental investment.
Inclusive fitness hypothesis
Although the signaler might suffer premature death, the squirrel’s aunts, uncles, brothers, sisters, father, mother, and cousins all benefit. According to this hypothesis, the signal alerts the “vehicles” that contain copies of the squirrel’s genes, providing an inclusive fitness benefit.
The critical test comes with female ground squirrels that do not have daughters or other children around but do have other genetic relatives in the vicinity. Do they still alarm call
when they spot a predator?
The answer is yes. Females without their own children still sound the alarm, as long as they have sisters, nieces, and aunts in the area.
kin classifcation systems
specific terms that describe types of kin such as mother, father, sister, brother, uncle, aunt, nephew, niece, and grandmother.
Genealogical distance
refers to how close (e.g., parents and siblings) or distant (second-degree or third-degree cousins) the kin are.
Social rank
refers to relative age, with the older being more highly ranked than the younger.
Group membership
distinguishes different clumps of kin, such as maternal versus paternal kin or same-sex versus opposite-sex
siblings.
physical similarity or phenotypic resemblance
similarity between your face or body and the faces and bodies of others. Evidence supports the hypothesis
that people do indeed use facial resemblance as a cue to kinship relatedness
Can humans also detect kinship among strangers or groups of other people to whom they are not related?
Evidence suggests they can—also based on facial resemblance
In sum, humans have at least four ways of identifying kin:
(1) through association; (2) through odor; (3) through kin classifcation generated by a universal grammar of three
cognitive building blocks; and (4) through facial similarity or phenotypic resemblance.
Researchers studied helping among 300 adult women from Los Angeles, ages 35 to 45. The predictions:
(1) Among kin, helping will increase as a function of genetic relatedness.
(2) among kin, helping will increase as the recipient’s reproductive value increases.
Helping should decrease as a function of the age of the recipient. In studies to test these hypotheses, researchers distinguished between two types of helping:
(1) helping that is substantial, such as acts that afect whether the recipient will live or die
(2) helping that is relatively trivial, such as giving someone a little spare change.
Kinship has a strong influence over ___________________ in many cultures
sharing food resources
Two other indications of emotional closeness are:
the frequency of contact and doing favors
Because of the critical importance of success in the mating game, it would be surprising if individuals were indifferent to the mating relationships of their kin. A study tested two hypotheses:
(1) Individuals will maintain greater vigilance over the mating relationships of their close than distant kin
(2) individuals will maintain greater vigilance over the mating of their female than male kin
Which living situation showed the most amount of cortisol in children?
1. Children living in nuclear families with both parents
2. Children living only with a single mother
3. Children living only with a single mother but with other close kin in the house
4. Children in households with a stepfather and half sibs
Children in households with a stepfather and half sibs
Smith, Kish, and Crawford (1987) tested three predictions about patterns of inheritance:
(1) People will leave more of their estates to genetically related kin and spouses than to unrelated people.
(2) People will leave more to close kin than to distantly related kin.
(3) People will leave more to offspring than to siblings, even though the average genetic relatedness is the same
in these two types of relationships.
