all in the family many issues related to family life, particularly dealing with children, related...
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All in the FamilyAll in the Family
Many issues related to family life, particularly dealing with children, related to parental investment theory (Trivers, 1972)
Many issues related to family life, particularly dealing with children, related to parental investment theory (Trivers, 1972)
Mothers provide more parental care than fathers. Why?
Mothers provide more parental care than fathers. Why?
Some maternal investment is obligatory Paternity uncertainty hypothesis Abandonability hypothesis Mating opportunity cost hypothesis
Some maternal investment is obligatory Paternity uncertainty hypothesis Abandonability hypothesis Mating opportunity cost hypothesis
Investing in ChildrenInvesting in Children
Allocating resources to an infant not only limits one’s own ontogeny and mating efforts, but also compromises opportunities to invest in other offspring, both those born and unborn
What factors influence decisions people make about investing in their offspring?
Allocating resources to an infant not only limits one’s own ontogeny and mating efforts, but also compromises opportunities to invest in other offspring, both those born and unborn
What factors influence decisions people make about investing in their offspring?
Childrearing in the Ancient Past: The Role of Alloparents
Childrearing in the Ancient Past: The Role of Alloparents
Alloparenting refers to the provisioning of care to children by individuals other than the genetic mother
Alloparenting is not unique to humans Communal suckling is often found in animals who live in
matrilineal groups, e.g., elephants, lions, cebus monkeys, and bats In traditional societies childrearing is performed by an
interconnected group of mainly female relatives Among the Ache, of eastern Paraguay, mothers with young
children forage less than women without children, but the deficit is made up through the efforts of other women, most (but not all) of them blood relatives
In many societies, “baby sitting” is done by pre-adolescent girls (often older siblings) and grandmothers
Alloparenting refers to the provisioning of care to children by individuals other than the genetic mother
Alloparenting is not unique to humans Communal suckling is often found in animals who live in
matrilineal groups, e.g., elephants, lions, cebus monkeys, and bats In traditional societies childrearing is performed by an
interconnected group of mainly female relatives Among the Ache, of eastern Paraguay, mothers with young
children forage less than women without children, but the deficit is made up through the efforts of other women, most (but not all) of them blood relatives
In many societies, “baby sitting” is done by pre-adolescent girls (often older siblings) and grandmothers
The Calculus of Maternal InvestmentThe Calculus of Maternal Investment
Mothers will invest most in children who have the greatest chance of reaching reproductive age, and thus carrying forth the mother’s genes
Mothers who are adept at identifying cues to a child’s future reproductive success are more likely to invest the most time, energy, and resources in those children
Mothers will invest most in children who have the greatest chance of reaching reproductive age, and thus carrying forth the mother’s genes
Mothers who are adept at identifying cues to a child’s future reproductive success are more likely to invest the most time, energy, and resources in those children
Reduced maternal care can take many formsReduced maternal care can take many forms
Neglect/abuse Receiving less attention, medical care, and food than they
might need Fostering out the child with relatives Oblation (leaving the child in the custody of some religious
institution) Abandonment
Infanticide/Filicide
Neglect/abuse Receiving less attention, medical care, and food than they
might need Fostering out the child with relatives Oblation (leaving the child in the custody of some religious
institution) Abandonment
Infanticide/Filicide
Factors Influencing amount of maternal investment
Factors Influencing amount of maternal investment
Child’s health Child’s age Mother’s reproductive status Social support Parent-child conflict
Child’s health Child’s age Mother’s reproductive status Social support Parent-child conflict
Child’s health Child’s health
Children with mental retardation or who have other congenital defects, such as Down’s syndrome, spina bifida, cystic fibrosis, or cleft palate, are abused at rates two to ten times higher than are nonafflicted children
Mann (1992) looked at maternal investment in seven pairs of premature and extremely low-birth weight twins in the United States
At 8-months (but not at 4): Every single one of the mothers demonstrated more positive behavior toward the healthier of the two infants, support for “healthy baby hypothesis”
Infanticide: The intentional killing or abandonment of children who were deformed or seriously ill was noted in 21 of the 35 traditional societies
Children with mental retardation or who have other congenital defects, such as Down’s syndrome, spina bifida, cystic fibrosis, or cleft palate, are abused at rates two to ten times higher than are nonafflicted children
Mann (1992) looked at maternal investment in seven pairs of premature and extremely low-birth weight twins in the United States
At 8-months (but not at 4): Every single one of the mothers demonstrated more positive behavior toward the healthier of the two infants, support for “healthy baby hypothesis”
Infanticide: The intentional killing or abandonment of children who were deformed or seriously ill was noted in 21 of the 35 traditional societies
Child’s ageChild’s age The reproductive value of a child increases with age, with the implication that mothers should be more likely to invest in older versus younger children
In traditional societies, when a child was born to a situation of scarce resources, he/she was more likely to be killed at birth. In situations involving an older sibling, the younger of the two was always the one put to death
Infanticide rare in modern societies, but does occur When an infant is killed, a natural parent is 7 times more likely to
be the perpetrator than a nonrelative, and the mother is more likely to commit the homicide than the father (especially neonatalcide)
The probability of a child being killed by a parent decreases sharply after the first year and continues to fall until young adulthood, when it is effectively zero
The reproductive value of a child increases with age, with the implication that mothers should be more likely to invest in older versus younger children
In traditional societies, when a child was born to a situation of scarce resources, he/she was more likely to be killed at birth. In situations involving an older sibling, the younger of the two was always the one put to death
Infanticide rare in modern societies, but does occur When an infant is killed, a natural parent is 7 times more likely to
be the perpetrator than a nonrelative, and the mother is more likely to commit the homicide than the father (especially neonatalcide)
The probability of a child being killed by a parent decreases sharply after the first year and continues to fall until young adulthood, when it is effectively zero
Children’s risk of homicide by a natural parent in relation to age (from Daly & Wilson,1988)
Children’s risk of homicide by a natural parent in relation to age (from Daly & Wilson,1988)
0
5
10
15
20
25
30
35
40
0 1-4 5-8 9-12 13-16 17
Child Age
Homicides per million children
Nonrelatives
Natural Parent
Mother’s reproductive statusMother’s reproductive status
As a woman’s reproductive years diminish, the cost of abandoning a child increases
Maternal age in U.S. is predictor of child abuse and infanticide
Canadian date for 1974 and 1983: teenage mothers were more than four times as likely to kill their infants as are mothers in their 20s
As a woman’s reproductive years diminish, the cost of abandoning a child increases
Maternal age in U.S. is predictor of child abuse and infanticide
Canadian date for 1974 and 1983: teenage mothers were more than four times as likely to kill their infants as are mothers in their 20s
Social supportSocial support
Mothers should only attempt to raise a child alone when conditions are favorable, such as having plentiful economic resources
When a mother lacks appropriate support or resources, lower parental investment in children is predicted
a mother’s marital status can be regarded as a cue to her availability of resources, and thus unmarried women would be expected, on average, to have less social support and limited access to resources
Single mothers are much more represented among infanticidal mothers than would be expected by chance
Although the magnitude is the greatest for teenage mothers, the difference does not disappear at later ages
Mothers should only attempt to raise a child alone when conditions are favorable, such as having plentiful economic resources
When a mother lacks appropriate support or resources, lower parental investment in children is predicted
a mother’s marital status can be regarded as a cue to her availability of resources, and thus unmarried women would be expected, on average, to have less social support and limited access to resources
Single mothers are much more represented among infanticidal mothers than would be expected by chance
Although the magnitude is the greatest for teenage mothers, the difference does not disappear at later ages
Paternal InvestmentPaternal Investment
Why Do Men Contribute as Much as They Do to Their Offspring?
Because of extended juvenile period, paternal investment needed to insure survival and success of offspring
Child survival and success is related to paternal investment, especially in environment of limited resources
Paternity certainty is moderately high in humans, increasing likelihood of paternal investment
Why Do Men Contribute as Much as They Do to Their Offspring?
Because of extended juvenile period, paternal investment needed to insure survival and success of offspring
Child survival and success is related to paternal investment, especially in environment of limited resources
Paternity certainty is moderately high in humans, increasing likelihood of paternal investment
Who are newborn babies said to resemble?Who are newborn babies said to resemble?
Newborns consistently said to resemble father more than mother. These claims especially likely to be made by mothers and mothers’ kin.
In actuality, babies to not likely to resemble father more than mother.
Gallup and colleagues found that men more likely to state they would invest in photos of children that looked like them. No effect in women.
Men in domestic violence treatment: those who rated their children as not looking like them inflicted more severe violence on their spouses
Newborns consistently said to resemble father more than mother. These claims especially likely to be made by mothers and mothers’ kin.
In actuality, babies to not likely to resemble father more than mother.
Gallup and colleagues found that men more likely to state they would invest in photos of children that looked like them. No effect in women.
Men in domestic violence treatment: those who rated their children as not looking like them inflicted more severe violence on their spouses
Grandparental InvestmentGrandparental Investment Grandmother hypothesis Who should be more certain that a grandchild is truly “theirs”? Euler & Weitzel (1996) asked 1,857 German adults to rate the
amount of care they had received from each of their grandparents up to age 7
Devotion of care 1. Maternal grandmothers 2. Maternal grandfathers 3. Paternal grandmothers 4. Paternal grandfathers
Maternal and paternal grandparents lived equally close to their grandchildren
A similar pattern has been observed for investment in offspring by maternal versus paternal aunts and uncles
Grandmother hypothesis Who should be more certain that a grandchild is truly “theirs”? Euler & Weitzel (1996) asked 1,857 German adults to rate the
amount of care they had received from each of their grandparents up to age 7
Devotion of care 1. Maternal grandmothers 2. Maternal grandfathers 3. Paternal grandmothers 4. Paternal grandfathers
Maternal and paternal grandparents lived equally close to their grandchildren
A similar pattern has been observed for investment in offspring by maternal versus paternal aunts and uncles
One published exception: Alexander Pashos (2000)One published exception: Alexander Pashos (2000)Germany, urban Greece, and rural Greece Pattern reversed for rural Greeks In rural Greece, paternal grandparents have the social
obligation of caring for their grandchildren, particularly for their grandsons, who are their primary heirs.
The increased physical closeness of the paternal family may result in greater paternity certainty than in urban settings.
When the movements of women (daughters-in-law) are known and controlled in part by the husband’s family, there is little uncertainty about paternity.
As a result, investment of the paternal family in the grandchildren can be expected to be enhanced, given the patrilineal traditions of the society.
Germany, urban Greece, and rural Greece Pattern reversed for rural Greeks In rural Greece, paternal grandparents have the social
obligation of caring for their grandchildren, particularly for their grandsons, who are their primary heirs.
The increased physical closeness of the paternal family may result in greater paternity certainty than in urban settings.
When the movements of women (daughters-in-law) are known and controlled in part by the husband’s family, there is little uncertainty about paternity.
As a result, investment of the paternal family in the grandchildren can be expected to be enhanced, given the patrilineal traditions of the society.
Stepparent Investment: Cinderella or Marsha
Brady? Stepparent Investment: Cinderella or Marsha
Brady? Stepparents should show little interest in the welfare of
children who are clearly not their biological offspring Why should stepfathers invest at all? Stepparenting as mating opportunity. The best strategy for a
man when looking for a new mate may be to act solicitously toward the potential mate’s children
It’s more difficult for stepparents to develop strong emotional bonds with stepchildren than with biological children
In one study of middle-class stepfamilies in the United States, only 53% of stepfathers and 25% of stepmothers claimed to have any “parental feelings” whatsoever for their stepchildren (Duberman, 1975)
Stepparents should show little interest in the welfare of children who are clearly not their biological offspring
Why should stepfathers invest at all? Stepparenting as mating opportunity. The best strategy for a
man when looking for a new mate may be to act solicitously toward the potential mate’s children
It’s more difficult for stepparents to develop strong emotional bonds with stepchildren than with biological children
In one study of middle-class stepfamilies in the United States, only 53% of stepfathers and 25% of stepmothers claimed to have any “parental feelings” whatsoever for their stepchildren (Duberman, 1975)
How much do stepparents invest?How much do stepparents invest?
Anderson et al. (1999a,b): South Africa & U.S.: stepfathers spent significantly more money on their natural children than on their stepchildren
Zvoch, 1999: Stepfamilies saved less money for their children’s education, started savings accounts for children later, and expected to spend less money for their child’s education in the future.
Stepfathers spend significantly less time with their stepchildren than with their natural children (3 hours less per week with their stepchildren than with their natural children); play with them less often. Pattern found cross culturally: U.s. South Africa, Caribbean islands
less money is spent on food when a child is reared by an adoptive, foster, or stepmother than a biological mother (Case et al.)
Anderson et al. (1999a,b): South Africa & U.S.: stepfathers spent significantly more money on their natural children than on their stepchildren
Zvoch, 1999: Stepfamilies saved less money for their children’s education, started savings accounts for children later, and expected to spend less money for their child’s education in the future.
Stepfathers spend significantly less time with their stepchildren than with their natural children (3 hours less per week with their stepchildren than with their natural children); play with them less often. Pattern found cross culturally: U.s. South Africa, Caribbean islands
less money is spent on food when a child is reared by an adoptive, foster, or stepmother than a biological mother (Case et al.)
“Wicked” stepparents?“Wicked” stepparents?
Daly & Wilson, in survey of Canadian households: Children were 40 times more likely to be abused if they lived with a stepparent versus two natural parents.
This difference remained even when possible influencing factors that may be associated with stepfamilies, such as poverty, the mother’s age, and family size, were statistically controlled. Given these and similar findings
“Stepparenthood per se remains the single most powerful risk factor for child abuse that has yet been identified.”
Child homicide: Studies in different countries report that for children under 2-years of age, homicide 40 to 100 times more likely at hands of stepparent (usually stepfather) than natural parent.
Daly & Wilson, in survey of Canadian households: Children were 40 times more likely to be abused if they lived with a stepparent versus two natural parents.
This difference remained even when possible influencing factors that may be associated with stepfamilies, such as poverty, the mother’s age, and family size, were statistically controlled. Given these and similar findings
“Stepparenthood per se remains the single most powerful risk factor for child abuse that has yet been identified.”
Child homicide: Studies in different countries report that for children under 2-years of age, homicide 40 to 100 times more likely at hands of stepparent (usually stepfather) than natural parent.
The risk of being killed by a stepparent versus a natural parent in relation to child’s age: Canada, 1974-1983 (from
Day & Wilson, 1988)
The risk of being killed by a stepparent versus a natural parent in relation to child’s age: Canada, 1974-1983 (from
Day & Wilson, 1988)
0
50
100
150
200
250
300
350
400
450
500
550
600
650
0-2 3-5 6-8 9-17
Age of Child
Homicide Rate per Million Children
Natural Parents
Stepparents
Parent-child conflict (Trivers, 1974)Parent-child conflict (Trivers, 1974)
Parents and siblings share 50% of their genes; siblings share 50% of their genes
Parents, all other things being equal, will want to treat each child equally (all children share 50% of their genes with the parent)
Each offspring will want more investment than a parent wants to give, especially in multi-child families
Genetic conflict of interest
Parents and siblings share 50% of their genes; siblings share 50% of their genes
Parents, all other things being equal, will want to treat each child equally (all children share 50% of their genes with the parent)
Each offspring will want more investment than a parent wants to give, especially in multi-child families
Genetic conflict of interest
Trivers proposed that parents and their offspring would have conflict over three major issues:
Trivers proposed that parents and their offspring would have conflict over three major issues:
The period of time parents should continue to invest in a given offspring (parents will want to di vest earlier than offspring);
The amount of investment a parent should impart to an individual offspring (each child will want more parental investment than parents want to give); and
The amount of altruism that an offspring should demonstrate to other relatives, particularly siblings (parents will encourage children to value siblings more than they are inclined to)
The period of time parents should continue to invest in a given offspring (parents will want to di vest earlier than offspring);
The amount of investment a parent should impart to an individual offspring (each child will want more parental investment than parents want to give); and
The amount of altruism that an offspring should demonstrate to other relatives, particularly siblings (parents will encourage children to value siblings more than they are inclined to)
Competition between siblings leads to the scarcity of resources, thus endangering the wellbeing of
both siblings
Competition between siblings leads to the scarcity of resources, thus endangering the wellbeing of
both siblings
One such circumstance that provides grounds for this type of parent-offspring conflict is the occurrence of twins. In some traditional societies, when resources are scarce, only one of the twins is allowed to survive, permitting the parents to invest their already scarce resources into only one individual
The child who is killed will often be the second born, the weaker, or the female
One such circumstance that provides grounds for this type of parent-offspring conflict is the occurrence of twins. In some traditional societies, when resources are scarce, only one of the twins is allowed to survive, permitting the parents to invest their already scarce resources into only one individual
The child who is killed will often be the second born, the weaker, or the female
Sibling cooperation and conflictSibling cooperation and conflict Conflict between siblings is common, but so also is warmth and
companionship Consequence of birth of a sibling Security of attachment measured late in pregnancy of 2nd child &
again 4- 8-weeks after birth (Teti et al., 1996) Security of attachment declined, with the decline being greatest for
children 2-years of age and older. first-born preschool girls, who had a positive relation with their
mothers before a second child was born, reacted particularly negatively to the birth of a new sibling (Dunn & Kendrick, 1981).
14 months after the birth of their sibling, these girls were hostile and negative to their new baby brothers and sisters, and the second-borns similarly had developed a negative attitude toward their older sibling.
Conflict between siblings is common, but so also is warmth and companionship
Consequence of birth of a sibling Security of attachment measured late in pregnancy of 2nd child &
again 4- 8-weeks after birth (Teti et al., 1996) Security of attachment declined, with the decline being greatest for
children 2-years of age and older. first-born preschool girls, who had a positive relation with their
mothers before a second child was born, reacted particularly negatively to the birth of a new sibling (Dunn & Kendrick, 1981).
14 months after the birth of their sibling, these girls were hostile and negative to their new baby brothers and sisters, and the second-borns similarly had developed a negative attitude toward their older sibling.
Cooperation among siblingsCooperation among siblings
Most cultures encourage cooperation/affiliation among sibs, making it difficult to claim such cooperation is result of evolved mechanisms rather than cultural traditions.
Jankowiak and Diderich (2000) interviewed families from a polygamous, Mormon community in the SW U.S.
father is the head of the family and the official dogma of family life is that all of a man’s children are equal
unity of the family, with the father as head, is stressed in church services, Sunday school, and in local schools.
Children (officially) get their family identification through the father, not the mother, and cooperation within the polygamous family is paramount.
The social stereotype, then, is for a high degree of within-family cooperation, with no distinction between full and half siblings (same father, different mother).
Most cultures encourage cooperation/affiliation among sibs, making it difficult to claim such cooperation is result of evolved mechanisms rather than cultural traditions.
Jankowiak and Diderich (2000) interviewed families from a polygamous, Mormon community in the SW U.S.
father is the head of the family and the official dogma of family life is that all of a man’s children are equal
unity of the family, with the father as head, is stressed in church services, Sunday school, and in local schools.
Children (officially) get their family identification through the father, not the mother, and cooperation within the polygamous family is paramount.
The social stereotype, then, is for a high degree of within-family cooperation, with no distinction between full and half siblings (same father, different mother).
Jankowiak and Diderich interviewed 70 individuals from 32 polygamous families who had both full and half siblings about issues related to solidarity
Jankowiak and Diderich interviewed 70 individuals from 32 polygamous families who had both full and half siblings about issues related to solidarity
lending money baby sitting for a sibling (functional solidarity) feelings of closeness to their various siblings nominated their favorite baby in the paternal household
(affectional solidarity) they were asked a series of questions concerning how
frequently they interacted with one another, such as attending birthday parties and weddings.
lending money baby sitting for a sibling (functional solidarity) feelings of closeness to their various siblings nominated their favorite baby in the paternal household
(affectional solidarity) they were asked a series of questions concerning how
frequently they interacted with one another, such as attending birthday parties and weddings.
Percentage of full and half siblings nominated for different measures of solidarity (based on data from
Jankowiak & Diderich, 2000)
Percentage of full and half siblings nominated for different measures of solidarity (based on data from
Jankowiak & Diderich, 2000)
0 10 20 30 40 50 60 70 80 90 100
Attend wedding reception
Attend birthdays
Favorite baby
Feelings of closeness
Ask to babysit
Give money
Half sibs
Full sibs
Incest AvoidanceIncest Avoidance Westermark (childhood familiarity results in incest avoidance)
versus Freud (Oedipal and Electra complexes)
Wolf: “minor marriages” in Taiwan Compared to “major marriages,” minor produced 40% fewer children had three times higher divorce rate wives more likely to admit to extramarital affairs
Shepher: Israeli kibbutzim Of 2869 couples from 211 kibbutzim, no marriages between
members from the same kibbutz.
Westermark (childhood familiarity results in incest avoidance) versus Freud (Oedipal and Electra complexes)
Wolf: “minor marriages” in Taiwan Compared to “major marriages,” minor produced 40% fewer children had three times higher divorce rate wives more likely to admit to extramarital affairs
Shepher: Israeli kibbutzim Of 2869 couples from 211 kibbutzim, no marriages between
members from the same kibbutz.
Bevc & SilvermanBevc & Silverman Study 1: Questionnaires to 500 college students “Mature” post-childhood sexual activity (attempted or
successful intercourse) more frequent among siblings who had been separated early in childhood than nonseparated siblings
Separation did not predict incidence of “immature” post-childhood sexual behavior, e.g., fondling, exhibitionism
Study 2: Response to newspaper ad on sibling sexual activities Replicated findings of first study Sibling pairs who were separated during early childhood were
more likely to have engaged in genital intercourse than nonseparated pairs, although there was no effect of separation for “immature” sexual behaviors.
Study 1: Questionnaires to 500 college students “Mature” post-childhood sexual activity (attempted or
successful intercourse) more frequent among siblings who had been separated early in childhood than nonseparated siblings
Separation did not predict incidence of “immature” post-childhood sexual behavior, e.g., fondling, exhibitionism
Study 2: Response to newspaper ad on sibling sexual activities Replicated findings of first study Sibling pairs who were separated during early childhood were
more likely to have engaged in genital intercourse than nonseparated pairs, although there was no effect of separation for “immature” sexual behaviors.
Post-adoption incest and genetic sexual attractionPost-adoption incest and genetic sexual attraction
highly intense, sexual attraction, often leading to incestuous relations, experienced by close kin who have been separated at or soon after birth and reunited as adults.
Most data on this phenomenon are anecdotal
Greenberg and Littlewood’s (1995) survey of post-adoption counselors in London indicated that about 50% of clients who had been reunited with kin as adults experienced, “strong, sexual feelings.”
highly intense, sexual attraction, often leading to incestuous relations, experienced by close kin who have been separated at or soon after birth and reunited as adults.
Most data on this phenomenon are anecdotal
Greenberg and Littlewood’s (1995) survey of post-adoption counselors in London indicated that about 50% of clients who had been reunited with kin as adults experienced, “strong, sexual feelings.”
Mechanisms for Westermark effectMechanisms for Westermark effect
Olfaction Evidence of the functions of pheromones in animals and
humans for both kin recognition and sexual attraction Parents can distinguish between the odors of their
biological children, except in the case of identical twins Mothers cannot identify stepchildren by odor Preadolescent children can identify their full sibs but not
half sibs or stepsibs by odor Olfactory cues may mediate favoritism of blood relatives
Olfaction Evidence of the functions of pheromones in animals and
humans for both kin recognition and sexual attraction Parents can distinguish between the odors of their
biological children, except in the case of identical twins Mothers cannot identify stepchildren by odor Preadolescent children can identify their full sibs but not
half sibs or stepsibs by odor Olfactory cues may mediate favoritism of blood relatives
Weisfeld et al. (2003), studying human familiesWeisfeld et al. (2003), studying human families
immediate family members exhibited particular patterns of aversions to each other’s odors.
Fathers showed aversions to their daughters’, but not to their sons’ odors.
Mothers did not display any aversions Opposite-sexed, but not same-sexed sibling pairs, showed
aversions to each other’s odors. These patterns occurred whether or not the source of the
odor was recognized, and whether or not the individuals involved were biologically related.
immediate family members exhibited particular patterns of aversions to each other’s odors.
Fathers showed aversions to their daughters’, but not to their sons’ odors.
Mothers did not display any aversions Opposite-sexed, but not same-sexed sibling pairs, showed
aversions to each other’s odors. These patterns occurred whether or not the source of the
odor was recognized, and whether or not the individuals involved were biologically related.
Dispositions toward social lifeDispositions toward social life
Judith Harris proposed that human group behavior is predicated on four evolutionary adaptations that humans share with other primates.
group affiliation and in-group favoritism fear of, and/or hostility toward, strangers within-group status seeking the seeking and establishment of close dyadic relationships
These “evolutionary adaptations” are though of as built-in predispositions, which are operating early in life but nonetheless develop over childhood.
Judith Harris proposed that human group behavior is predicated on four evolutionary adaptations that humans share with other primates.
group affiliation and in-group favoritism fear of, and/or hostility toward, strangers within-group status seeking the seeking and establishment of close dyadic relationships
These “evolutionary adaptations” are though of as built-in predispositions, which are operating early in life but nonetheless develop over childhood.
The problem of altruismThe problem of altruism
Altruism difficult to explain from selfish gene theory Altruism among kin consistent with inclusive fitness
theory How can altruism toward nonkin be explained? Altruism among nonkin observed in all groups of humans
and throughout history Altruism observed in other social animals (e.g., vampire
bats, chimpanzees)
Altruism difficult to explain from selfish gene theory Altruism among kin consistent with inclusive fitness
theory How can altruism toward nonkin be explained? Altruism among nonkin observed in all groups of humans
and throughout history Altruism observed in other social animals (e.g., vampire
bats, chimpanzees)
Reciprocal AltruismReciprocal Altruism
Cooperation between two or more individuals for mutual benefit.
Cooperation between individuals, with the expectation that “one good term deserves another,” i.e. quid pro quo
Similarly, aggression/cheating will also be responded to in kind
In some primates, including humans and chimpanzees, cooperation expressed in terms of alliances
Cooperation between two or more individuals for mutual benefit.
Cooperation between individuals, with the expectation that “one good term deserves another,” i.e. quid pro quo
Similarly, aggression/cheating will also be responded to in kind
In some primates, including humans and chimpanzees, cooperation expressed in terms of alliances
Social contract theory (Cosmides & Toobey)Social contract theory (Cosmides & Toobey)
Capacities needed:
1. The ability to recognize many different individual humans.
2. The ability to remember some aspects of the histories of interactions with different individuals.
3. The ability to communicate one’s values to others. 4. The ability to model the values of others. 5. The ability to represent costs and benefits, independent
of the particular items exchanged.
Capacities needed:
1. The ability to recognize many different individual humans.
2. The ability to remember some aspects of the histories of interactions with different individuals.
3. The ability to communicate one’s values to others. 4. The ability to model the values of others. 5. The ability to represent costs and benefits, independent
of the particular items exchanged.
Wason taskWason task
“If a card has a vowel on one side, then it must
have an even number on the other side. You must determine
if the set of cards in front of you conform to the rule or not,
and you should turn over the fewest number of cards
to determine the truth of the rule.
A G 2 7
“If a card has a vowel on one side, then it must
have an even number on the other side. You must determine
if the set of cards in front of you conform to the rule or not,
and you should turn over the fewest number of cards
to determine the truth of the rule.
A G 2 7
Answer: A 7 Answer: A 7
“If a person is drinking alcohol, then he or she must be at least 21 years old.”
“If a person is drinking alcohol, then he or she must be at least 21 years old.”
Beer Coke 16 years old25 years old
Beer 16 years old
Beer Coke 16 years old25 years old
Beer 16 years old
Deontic reasoningDeontic reasoning
Reasoning about one may, should,or ought to do. Contrast with descriptive or indicative reasoning, which is
reasoning about “facts” and does not involve a violation of social rules
When does deontic reasoning first appear?
Reasoning about one may, should,or ought to do. Contrast with descriptive or indicative reasoning, which is
reasoning about “facts” and does not involve a violation of social rules
When does deontic reasoning first appear?
Harris & Nunez, working with 3- and 4-year oldsHarris & Nunez, working with 3- and 4-year olds
“One day Carol wants to do some painting. Her Mom says if she does some painting she should wear her apron.” (deontic)
“One day Carol wants to do some painting. Carol says that if she does some painting she always puts her apron on.” (descriptive)
Children given 4 drawings Carol painting with her apron Carol painting without her apron Carol not painting with her apron Carol not painting without her apron
“One day Carol wants to do some painting. Her Mom says if she does some painting she should wear her apron.” (deontic)
“One day Carol wants to do some painting. Carol says that if she does some painting she always puts her apron on.” (descriptive)
Children given 4 drawings Carol painting with her apron Carol painting without her apron Carol not painting with her apron Carol not painting without her apron
Deontic condition: “Show me the picture where Carol is doing something naughty, and not doing what her Mom said.”
Descriptive condition: “Show me the picture where Carol is doing something different and not doing what she said.”
Percentage correct: Deontic condition: 72% and 83% (3- and 4-year olds) Descriptive condition: 40% (both 3- and 4-year olds)
Deontic condition: “Show me the picture where Carol is doing something naughty, and not doing what her Mom said.”
Descriptive condition: “Show me the picture where Carol is doing something different and not doing what she said.”
Percentage correct: Deontic condition: 72% and 83% (3- and 4-year olds) Descriptive condition: 40% (both 3- and 4-year olds)
The psychology of friendshipThe psychology of friendship
Is friendship based on reciprocal altruisms? Is friendship based on reciprocal altruisms?
Benefits and Opposite-sex friendships (Bleske &
Buss) Benefits and Opposite-sex friendships (Bleske &
Buss) Men, more than women, view opposite-sex
friendships as possible sexual access. Women, more than men, view opposite -sex
friendship as possible provision of protection. Opposite -sex friendship provides information
about the opposite sex Both men and women perceive little intrasex rivalry from
opposite-sex friendships, although they do from same-sex friendships, especially men
Men, more than women, view opposite-sex
friendships as possible sexual access. Women, more than men, view opposite -sex
friendship as possible provision of protection. Opposite -sex friendship provides information
about the opposite sex Both men and women perceive little intrasex rivalry from
opposite-sex friendships, although they do from same-sex friendships, especially men
Types of social relationships: Interactions, relations, structure (life in groups) - from Hinde
(1976)
Types of social relationships: Interactions, relations, structure (life in groups) - from Hinde
(1976) Interactions occur between two individuals and contain one or
more types of behavior.
Relationships are interactions between two individuals over time.
Structure is the description of social behavior at the group level.
Dominance is a construct that can be used to explain social structure, or the processes by which social groups stay together.
Interactions occur between two individuals and contain one or more types of behavior.
Relationships are interactions between two individuals over time.
Structure is the description of social behavior at the group level.
Dominance is a construct that can be used to explain social structure, or the processes by which social groups stay together.
InteractionInteraction
In infancy, roots of social (reciprocal) interaction
During the toddler period, children engage in “games,” characterized by mutual gaze, patterned exchanges, turn taking, and reciprocal imitation
One robust sex difference relevant to social interactions concerns females’ greater orientation toward other people.
In infancy, roots of social (reciprocal) interaction
During the toddler period, children engage in “games,” characterized by mutual gaze, patterned exchanges, turn taking, and reciprocal imitation
One robust sex difference relevant to social interactions concerns females’ greater orientation toward other people.
Zahn-Waxler and her colleagues (1992)Zahn-Waxler and her colleagues (1992)
12- and 20-month-old children’s response to the distress of other people.
girls more often tried to comfort the distressed individual and sought information about the persons distress (“What’s wrong?”) than did boys.
Girls displayed facial expressions, such as sad looks, and made sympathetic statements or gestures to indicate their concern more than boys, who were more apt to be nonresponsive to the distress of others.
12- and 20-month-old children’s response to the distress of other people.
girls more often tried to comfort the distressed individual and sought information about the persons distress (“What’s wrong?”) than did boys.
Girls displayed facial expressions, such as sad looks, and made sympathetic statements or gestures to indicate their concern more than boys, who were more apt to be nonresponsive to the distress of others.
Peer-directed aggression is first observed at the end of the first year of life and typically occurs in the context of object disputes (Coie & Dodge, 1998).
Up to 50% of the interaction between toddlers is conflictual (up to 50%), though not aggressive
Peer-directed aggression is first observed at the end of the first year of life and typically occurs in the context of object disputes (Coie & Dodge, 1998).
Up to 50% of the interaction between toddlers is conflictual (up to 50%), though not aggressive
Interactions during childhoodInteractions during childhood
During childhood, peer social interaction focuses on play Sex segregation common Physical aggression during early childhood, relative to
toddlerhood, decreases while verbal aggression shows the opposite pattern (Coie & Dodge, 1998).
Relational aggression: manipulating social relations by shunning and spreading rumors, among other strategies.
Relational aggression increases with age as children’s cognitive abilities improve, but is used more by girls than boys
During childhood, peer social interaction focuses on play Sex segregation common Physical aggression during early childhood, relative to
toddlerhood, decreases while verbal aggression shows the opposite pattern (Coie & Dodge, 1998).
Relational aggression: manipulating social relations by shunning and spreading rumors, among other strategies.
Relational aggression increases with age as children’s cognitive abilities improve, but is used more by girls than boys
Bullies and victimsBullies and victims
The form of aggression that comes to the fore during late childhood and adolescence is bullying and victimization
Bullies are more frequently boys than girls and represent about 10% of the elementary school population in most industrialized counties
boys use physical aggression in bullying same-sex peers and girls use relational aggression with other girls
Victims of bullies tend to be physically frail children with few friends or affiliates
The form of aggression that comes to the fore during late childhood and adolescence is bullying and victimization
Bullies are more frequently boys than girls and represent about 10% of the elementary school population in most industrialized counties
boys use physical aggression in bullying same-sex peers and girls use relational aggression with other girls
Victims of bullies tend to be physically frail children with few friends or affiliates
Aggression as a solution to adaptive problemsAggression as a solution to adaptive problems
Co-opt resources of others Defend against an attack Inflict costs on intrasexual rivals Negotiate status and power hierarchies Deter rivals from future aggression Deter long-term mates from sexual infidelity
Co-opt resources of others Defend against an attack Inflict costs on intrasexual rivals Negotiate status and power hierarchies Deter rivals from future aggression Deter long-term mates from sexual infidelity
Potential benefits of aggression must be balanced with costs
Potential benefits of aggression must be balanced with costs
Aggression tends to cause retaliatory aggression Aggression to maintain reputation and status “Honor” killings of sisters/daughters to maintain status in
community Willingness of victim to retaliate Reputation as both a bully or victim can be deleterious
Aggression tends to cause retaliatory aggression Aggression to maintain reputation and status “Honor” killings of sisters/daughters to maintain status in
community Willingness of victim to retaliate Reputation as both a bully or victim can be deleterious
Young-male syndromeYoung-male syndrome
Males, at all ages, engage in more physical aggression than females and the aggression that adolescent and young-adult males engage in is more likely to lead to serious injury and sometimes death
Greater male aggression can be explained in terms of parental investment theory
Intrasex competitionImpress females via competitive risk taking
Risk taking and accidents are frequently the result of competitive or “show-off” behavior, with the purpose being to compete with other members of the same sex or to impress members of the opposite sex
Males, at all ages, engage in more physical aggression than females and the aggression that adolescent and young-adult males engage in is more likely to lead to serious injury and sometimes death
Greater male aggression can be explained in terms of parental investment theory
Intrasex competitionImpress females via competitive risk taking
Risk taking and accidents are frequently the result of competitive or “show-off” behavior, with the purpose being to compete with other members of the same sex or to impress members of the opposite sex
Death rates dues to vehicular accidents per 100,000 resident population in the United States for males and
females, 1995-1997
Death rates dues to vehicular accidents per 100,000 resident population in the United States for males and
females, 1995-1997
0
10
20
30
40
50
5-14 15-24 25-34 35-44 45-64
Years in Age
Vehicular Accident Rate
Males
Females
Percentage of trauma admissions for violence at LA Medical Center for 3 months in 1990, by age (adapted from Cairns et
al., 1991)
Percentage of trauma admissions for violence at LA Medical Center for 3 months in 1990, by age (adapted from Cairns et
al., 1991)
0
20
40
60
80
0-4 5-9 10-14 15-19 20-24 25-29 30-34
Age in Years
Percentage of Violent Admissions
Contexts triggering men’s intrasex aggressionContexts triggering men’s intrasex aggression
Marital and employment status: being unemployed and unmarried associated with greater tendency to be aggressive
Status and reputation Sexual jealousy and intrasexual rivalry
Marital and employment status: being unemployed and unmarried associated with greater tendency to be aggressive
Status and reputation Sexual jealousy and intrasexual rivalry
Contexts triggering male aggression against femalesContexts triggering male aggression against females
Sexual jealousy (mate guarding) Characteristic of female victims of male violence:
Age (younger women) - as cue to reproductive value
Sexual jealousy (mate guarding) Characteristic of female victims of male violence:
Age (younger women) - as cue to reproductive value
Contexts triggering female intrasexual aggressionContexts triggering female intrasexual aggression
Serious female-on-female violence less frequent than for male-on-male violence
Relational aggression frequent in females Women, more often than men derogate their rivals on basis
of physical appearance and promiscuity; exclude other females form groups
Serious female-on-female violence less frequent than for male-on-male violence
Relational aggression frequent in females Women, more often than men derogate their rivals on basis
of physical appearance and promiscuity; exclude other females form groups
Context triggering female-on-male aggressionContext triggering female-on-male aggression
In domestic disputes, females as likely to batter males as males are to batter females
But the amount of damage inflicted by females is much less than that inflicted by males
Females typically attack males in defense of self or after prolonged history of abuse.
In domestic disputes, females as likely to batter males as males are to batter females
But the amount of damage inflicted by females is much less than that inflicted by males
Females typically attack males in defense of self or after prolonged history of abuse.
Adolescent and young-adult males are more likely to be both the victims and perpetrators of
homicide
Adolescent and young-adult males are more likely to be both the victims and perpetrators of
homicide
Homicide victimization rate per 100,000 resident population in the United States, 1995-1997: MalesHomicide victimization rate per 100,000 resident population in the United States, 1995-1997: Males
-10
10
30
50
70
90
110
130
150
1-14 15-24 25-44 45-64 65 +
Age in Years
Homicide Rate / 100,000
All Males
White Males
African American Males
Homicide victimization rate per 100,000 resident population in the United States, 1995-1997: Females
Homicide victimization rate per 100,000 resident population in the United States, 1995-1997: Females
0
20
40
60
80
100
1-14 15-24 25-44 45-64 65 +
Years in Age
Homicide Rate / 100,000
All Females
White Females
African American Females
Dominance hierarchiesDominance hierarchies
Status with a group Influences access to resources, such as food and mates Establishing high status achieved by combination of
aggression and cooperative interaction Dominance hierarchies:
Reduce antagonism within the group Distribute scare resources Focus division of labor
Status with a group Influences access to resources, such as food and mates Establishing high status achieved by combination of
aggression and cooperative interaction Dominance hierarchies:
Reduce antagonism within the group Distribute scare resources Focus division of labor
Establishing Dominance HierarchiesEstablishing Dominance Hierarchies
“leaders” recognized early,even in transient groups. In children, top and bottom of hierarchies established first,
middle areas later Even preverbal toddlers in groups form dominance
hierarchies In childhood, hierarchies usually in same-sex groups Interaction in same-sex groups serves to foster
development of social skills Children with mostly opposite-sex friends are less-well
adjusted than children with mostly same-sex friends (Kovacs et al., 1996)
“leaders” recognized early,even in transient groups. In children, top and bottom of hierarchies established first,
middle areas later Even preverbal toddlers in groups form dominance
hierarchies In childhood, hierarchies usually in same-sex groups Interaction in same-sex groups serves to foster
development of social skills Children with mostly opposite-sex friends are less-well
adjusted than children with mostly same-sex friends (Kovacs et al., 1996)
Both aggression and affiliative behaviors used to establish and maintain dominance
Both aggression and affiliative behaviors used to establish and maintain dominance
Evidence in: chimpanzees (de Waal) preschoolers (Hawley) school children and adolescence (Pellegrini)
In preschoolers level of aggression positively associated with popularity (Hawley; Vollenweider et al.)
Robbers Cave study (Sherif et al.) Fifth-grade boys at summer camp Rattlers and Eagles
Evidence in: chimpanzees (de Waal) preschoolers (Hawley) school children and adolescence (Pellegrini)
In preschoolers level of aggression positively associated with popularity (Hawley; Vollenweider et al.)
Robbers Cave study (Sherif et al.) Fifth-grade boys at summer camp Rattlers and Eagles
Sex differences in status strivingSex differences in status striving
Back to parental investment theory Status in men is important cue women use to determine
desirability in a mate Historically, high-status men have had access to multiple
mates In preschool, physical competition and rough-and-tumble
play more common in boys (Maccoby,1998) In adults, males score higher on social dominance
orientation scales than women (Pratto et al.)
Back to parental investment theory Status in men is important cue women use to determine
desirability in a mate Historically, high-status men have had access to multiple
mates In preschool, physical competition and rough-and-tumble
play more common in boys (Maccoby,1998) In adults, males score higher on social dominance
orientation scales than women (Pratto et al.)
Determinants and Correlates of DominanceDeterminants and Correlates of Dominance
Dominant “pose” - standing upright; expanded chest, looking at others while talking; smile a lot; point ot others while talking; walk fast (Argyle)
Height perceived to be related to dominance In U.S., among men, height related to:
promotions Salaries ($600/year per inch over 5’ 8”) Electability (in 83% of presidential elections,taller
candidate elected)
Dominant “pose” - standing upright; expanded chest, looking at others while talking; smile a lot; point ot others while talking; walk fast (Argyle)
Height perceived to be related to dominance In U.S., among men, height related to:
promotions Salaries ($600/year per inch over 5’ 8”) Electability (in 83% of presidential elections,taller
candidate elected)
Dominance and TestosteroneDominance and Testosterone
In animals, experimentally-manipulated levels of testosterone related to status in social group
In humans, levels of testosterone correlated with aspects of status and aggression. Cause-effect unclear, however.
In athletes, levels of testosterone rise immediately before a match; levels continue to rise for winners and decline for losers (Mazur)
Similar effects for nonathletic competition (chess) and for fans!
In animals, experimentally-manipulated levels of testosterone related to status in social group
In humans, levels of testosterone correlated with aspects of status and aggression. Cause-effect unclear, however.
In athletes, levels of testosterone rise immediately before a match; levels continue to rise for winners and decline for losers (Mazur)
Similar effects for nonathletic competition (chess) and for fans!
Dominance and NeurotransmittersDominance and Neurotransmitters
Serotonin levels associated with dominance Vervet monkeys: high-ranking males had almost twice the
levels of serotonin than low-ranking males (McGuire & Raliegh)
Loss of status results in drop of serotonin In college fraternity, officers had higher levels of serotonin
than nonofficers
Serotonin levels associated with dominance Vervet monkeys: high-ranking males had almost twice the
levels of serotonin than low-ranking males (McGuire & Raliegh)
Loss of status results in drop of serotonin In college fraternity, officers had higher levels of serotonin
than nonofficers
The Evolution of ConsciousnessThe Evolution of Consciousness
Consciousness: that naturally occurring cognitive representational capacity permitting explicit and reflective accounts of the – mostly causative – contents of mind, contents harbored by the psychological frame of the self and, as a consequence, also the psychological frames of others (Bering & Bjorklund).
Consciousness as self-awareness (self-consciousness) and theory of mind
Consciousness: that naturally occurring cognitive representational capacity permitting explicit and reflective accounts of the – mostly causative – contents of mind, contents harbored by the psychological frame of the self and, as a consequence, also the psychological frames of others (Bering & Bjorklund).
Consciousness as self-awareness (self-consciousness) and theory of mind
Evolution of the Human BrainEvolution of the Human Brain
Central to evolution of the modern human mind
Human intelligence emerged in response to certain social pressures
Increase in EQ over geologic time
Big brains, slow development, and social complexity
Central to evolution of the modern human mind
Human intelligence emerged in response to certain social pressures
Increase in EQ over geologic time
Big brains, slow development, and social complexity
EQ Evolution (Tobias, 1987)
3.14
5.5
7.6
012345678
A. afarensis H. habilis H. erectus H. sapiens
Species
Encephalization Quotient
Precursors to Consciousness: The Comparative Psychology of Consciousness
Precursors to Consciousness: The Comparative Psychology of Consciousness
How smart are chimpanzees? How much are they “like us”?
How smart are chimpanzees? How much are they “like us”?
“Humans are nothing more than naked apes, qualitatively no different from chimpanzees”
“Chimpanzees are merely clever animals, just as “Clever
Hans” was a clever horse.”
“Humans are nothing more than naked apes, qualitatively no different from chimpanzees”
“Chimpanzees are merely clever animals, just as “Clever
Hans” was a clever horse.”
Chimps are a lot like usChimps are a lot like us
Wolfgang Koeler’s chimpanzee Sultan (insight learning) Robert Yerkes’ chimpanzee,Prince Chim Howard and Trixie Gardner’s sign-language learning
chimpanzee Wahsoe Lynn Miles’ sign-language orangutan, Chantek, and Penny
Paterson’s gorilla,Koko Sue Savage-Rumbaugh’s pygmy chimpanzee, Kanzi Richard Byrnes & Andrew Whiten’s claims of
Machiavellian intelligence great apes (deception, perspective taking, “theory of mind”)
Wolfgang Koeler’s chimpanzee Sultan (insight learning) Robert Yerkes’ chimpanzee,Prince Chim Howard and Trixie Gardner’s sign-language learning
chimpanzee Wahsoe Lynn Miles’ sign-language orangutan, Chantek, and Penny
Paterson’s gorilla,Koko Sue Savage-Rumbaugh’s pygmy chimpanzee, Kanzi Richard Byrnes & Andrew Whiten’s claims of
Machiavellian intelligence great apes (deception, perspective taking, “theory of mind”)
Chimps are clever behavioristsChimps are clever behaviorists
Herbert Terrace’s chimpanzee Nim Chimpsky Chimpanzees and orangutans cannot take the perspective
of others, do not possess theory of mind, and do not display “true” imitation comparable to what human 3- and 4-year-old children show.
Herbert Terrace’s chimpanzee Nim Chimpsky Chimpanzees and orangutans cannot take the perspective
of others, do not possess theory of mind, and do not display “true” imitation comparable to what human 3- and 4-year-old children show.
Problem solving in the labProblem solving in the lab
Mirror self-recognitionMirror self-recognition
Can chimpanzees take the perspective of others?Can chimpanzees take the perspective of others?
Do they know that seeing is knowledge? Brian Hare, Michael Tomasello, & Josep Call
Food competition Begging from a sighted versus “blinded” experimenter
Daniel Povinelli
Do they know that seeing is knowledge? Brian Hare, Michael Tomasello, & Josep Call
Food competition Begging from a sighted versus “blinded” experimenter
Daniel Povinelli
A B
C D
E F
Can apes imitate?Can apes imitate?
Some have seen imitation as a low-level ability, what animals, young children, and unimaginative adults do.
Some have seen imitation as a low-level ability, what animals, young children, and unimaginative adults do.
Chimpanzees and orangutans possess “culture”Chimpanzees and orangutans possess “culture”
Intergenerational (nongenetic) transmission of acquired patterns of behavior
39 unique behaviors,across different chimpanzee troops have been identified including: Nut cracking Forms of greeting Forms of grooming Termite and ant fishing
Intergenerational (nongenetic) transmission of acquired patterns of behavior
39 unique behaviors,across different chimpanzee troops have been identified including: Nut cracking Forms of greeting Forms of grooming Termite and ant fishing
Termite fishingTermite fishing
Forms of Social LearningForms of Social Learning
Mimicry: The duplication of a behavior without any understanding of the goal of that behavior.
Emulation: One individual observes another interacting with an object to achieve a specific goal. That individual then interacts with the object attempting to attain the same end but does not duplicate the same behavior as the model to achieve that goal.
Imitation: Reproduction of observed behavior to achieve a specific goal. May require an understanding of the goal that the model had in mind, as well as the reproduction of important components of the observed behavior.
Mimicry: The duplication of a behavior without any understanding of the goal of that behavior.
Emulation: One individual observes another interacting with an object to achieve a specific goal. That individual then interacts with the object attempting to attain the same end but does not duplicate the same behavior as the model to achieve that goal.
Imitation: Reproduction of observed behavior to achieve a specific goal. May require an understanding of the goal that the model had in mind, as well as the reproduction of important components of the observed behavior.
Human social cognition an extension of ape cognition with addition of self-consciousness Human social cognition an extension of ape
cognition with addition of self-consciousness
Evolutionary Psychology and ConsciousnessEvolutionary Psychology and Consciousness
Consciousness as an epiphenomenon Evolved psychological mechanisms are implicit
(unavailable to consciousness), making consciousness an unnecessary post-hoc cognitive phenomenon
Pinker (1997): “If consciousness is useless – if a creature without it could negotiate the world as well as a creature with it – why would natural selection have favored the conscious one?”
Consciousness as an epiphenomenon Evolved psychological mechanisms are implicit
(unavailable to consciousness), making consciousness an unnecessary post-hoc cognitive phenomenon
Pinker (1997): “If consciousness is useless – if a creature without it could negotiate the world as well as a creature with it – why would natural selection have favored the conscious one?”
“Consciousness” is not found in the indexes of:“Consciousness” is not found in the indexes of:
Barkow, Tooby, and Cosmides (1992) The Adapted Mind Buss (1999/2004) Evolutionary Psychology Cartwright’s (2000) Evolution and Human Behavior, Pinker’s popular books The Language Instinct (1994) and The
Blank Slate (2002)
But consciousness receives considerable attention in other evolutionary psychology texts
Gaulin & McBurney, 2001 Palmer & Palmer, 2002 Pinker (1997) How the Mind Works
Barkow, Tooby, and Cosmides (1992) The Adapted Mind Buss (1999/2004) Evolutionary Psychology Cartwright’s (2000) Evolution and Human Behavior, Pinker’s popular books The Language Instinct (1994) and The
Blank Slate (2002)
But consciousness receives considerable attention in other evolutionary psychology texts
Gaulin & McBurney, 2001 Palmer & Palmer, 2002 Pinker (1997) How the Mind Works
Self-consciousness disrupted many ancient psychological adaptations that human beings share with other species and presented a new series of challenges that our distant human ancestors were never forced to grapple with.
These challenges were initially focused in the social realm, with self-consciousness producing individuals who were more keenly aware of their own knowledge and motivations and those of others.
Such awareness could have provided great advantages, but with it great problems.
Self-consciousness disrupted many ancient psychological adaptations that human beings share with other species and presented a new series of challenges that our distant human ancestors were never forced to grapple with.
These challenges were initially focused in the social realm, with self-consciousness producing individuals who were more keenly aware of their own knowledge and motivations and those of others.
Such awareness could have provided great advantages, but with it great problems.
The Adaptive Benefits of ConsciousnessThe Adaptive Benefits of Consciousness
Know thyself, and know others: TOM
Consciousness and the development of technological skills
Tool use and construction
Learning can extend beyond the immediate context and be applied to situations only imagined or in one’s memory (Mithen)
Learning/thinking “out of context”
Know thyself, and know others: TOM
Consciousness and the development of technological skills
Tool use and construction
Learning can extend beyond the immediate context and be applied to situations only imagined or in one’s memory (Mithen)
Learning/thinking “out of context”
Baron-Cohen’s Theory of Theory of MindBaron-Cohen’s Theory of Theory of Mind
ID (Identity Detection) EDD (Eye direction Detector) SAM (Shared-Attention Mechanisms) TOMM (Theory of mind module)
ID (Identity Detection) EDD (Eye direction Detector) SAM (Shared-Attention Mechanisms) TOMM (Theory of mind module)
The Challenges of ConsciousnessThe Challenges of Consciousness
Other minds, new problems.
Counterintuitive challenges of consciousness.
Self-consciousness began to interfere with adaptive functioning in the social domain, i.e., selfish motivations can be perceived by others as such
Others may detect signs of deception, e.g., through facial gestures and other behavioral cues
Evolution of self-deception (i.e., defense mechanisms a la Freud)
Other minds, new problems.
Counterintuitive challenges of consciousness.
Self-consciousness began to interfere with adaptive functioning in the social domain, i.e., selfish motivations can be perceived by others as such
Others may detect signs of deception, e.g., through facial gestures and other behavioral cues
Evolution of self-deception (i.e., defense mechanisms a la Freud)
Kierkegaard : “with every increase in the degree of consciousness, and in proportion to that increase, the intensity of despair increases: the more consciousness, the more intense the despair” (p. 345).
Consciousness is considered to pose adaptive challenges to human beings rather than to facilitate their genetic fitness (e.g., women’s knowledge of ovulation and behaving so not to get pregnant)
Kierkegaard : “with every increase in the degree of consciousness, and in proportion to that increase, the intensity of despair increases: the more consciousness, the more intense the despair” (p. 345).
Consciousness is considered to pose adaptive challenges to human beings rather than to facilitate their genetic fitness (e.g., women’s knowledge of ovulation and behaving so not to get pregnant)
How Previously Adaptive Social Behaviors Became Socially Maladaptive in Modern Human Beings
How Previously Adaptive Social Behaviors Became Socially Maladaptive in Modern Human Beings
Homicide, theft, rape, all can be adaptive in certain contexts, but lead to retaliation if the perpetrator is caught “in the act.”
These activities may be high in frequency in some primates because of: (a) the inability of potential “victims” to perceive the
hidden, aggressive intentions of potential “perpetrators”; (b) the inability of perpetrators to track others’ knowledge
of their behaviors, and; (c) the inability of observers to intentionally communicate
the occurrence of these transgressions to naïve others who did not witness the event
Homicide, theft, rape, all can be adaptive in certain contexts, but lead to retaliation if the perpetrator is caught “in the act.”
These activities may be high in frequency in some primates because of: (a) the inability of potential “victims” to perceive the
hidden, aggressive intentions of potential “perpetrators”; (b) the inability of perpetrators to track others’ knowledge
of their behaviors, and; (c) the inability of observers to intentionally communicate
the occurrence of these transgressions to naïve others who did not witness the event
Mindreading and communication of past events make such activities less frequent in humans
Intentions also count, e.g., was act committed “on purpose,” “accidentally,” etc.
Mindreading and communication of past events make such activities less frequent in humans
Intentions also count, e.g., was act committed “on purpose,” “accidentally,” etc.
The Role of Consciousness in Religion: Spirits, Gods, and Morality
The Role of Consciousness in Religion: Spirits, Gods, and Morality
Boyer: human cognition is naturally susceptible to supernatural agent concepts because such concepts violate
people’s intuitive ontological assumptions. gods and spirits are represented as being essentially
human, and as such activate our folk psychology systems (e.g., they can see and hear and think), but they are invisible, can walk through walls, etc.
People generalize their intentional stance from folk psychology (theory of mind) to explain natural phenomena and attribute them to spirits, gods, etc.
Boyer: human cognition is naturally susceptible to supernatural agent concepts because such concepts violate
people’s intuitive ontological assumptions. gods and spirits are represented as being essentially
human, and as such activate our folk psychology systems (e.g., they can see and hear and think), but they are invisible, can walk through walls, etc.
People generalize their intentional stance from folk psychology (theory of mind) to explain natural phenomena and attribute them to spirits, gods, etc.
Is Religion/Spirituality an Adaptation?Is Religion/Spirituality an Adaptation?
People are not good at hiding “sins,” and getting caught can lead to social damage.
Having an all-seeing, all-knowing spirit always watching you, helps people to behave morally and according to social prescriptions.
Religion/spirituality may have been adaptive, contributing to maintaining socially sanctioned behavior
Alternatively, spirituality may be by-product of folk psychology
People are not good at hiding “sins,” and getting caught can lead to social damage.
Having an all-seeing, all-knowing spirit always watching you, helps people to behave morally and according to social prescriptions.
Religion/spirituality may have been adaptive, contributing to maintaining socially sanctioned behavior
Alternatively, spirituality may be by-product of folk psychology
The Natural Emergence of ‘Afterlife’ Reasoning with Jesse Bering & Carlos Hernández Blasi
The Natural Emergence of ‘Afterlife’ Reasoning with Jesse Bering & Carlos Hernández Blasi
Preschoolers, 10/11-year olds; adults View puppet show of anthropomorphized mouse getting eaten
by alligator
Preschoolers, 10/11-year olds; adults View puppet show of anthropomorphized mouse getting eaten
by alligator
Participants asked series of questions about the continuity of biological, psychobiological, and psychological
functioning
Participants asked series of questions about the continuity of biological, psychobiological, and psychological
functioning
BiologicalBiological
Will he ever need to eat food again?”*
Does his brain still work?”*
Will he ever grow up to be an old mouse?”
Will he ever need to drink water again?”
Will he ever need to eat food again?”*
Does his brain still work?”*
Will he ever grow up to be an old mouse?”
Will he ever need to drink water again?”
PsychobiologicalPsychobiological
Is he still thirsty?”*
Is he still hungry?”*
Is he still sleepy?”
Does he still feel sick?”
Is he still thirsty?”*
Is he still hungry?”*
Is he still sleepy?”
Does he still feel sick?”
PerceptualPerceptual
Can he still hear the birds singing?”*
Can he still taste the yucky grass he ate?”*
Can he still smell the flowers?”
Can he see where he is?”
Can he still hear the birds singing?”*
Can he still taste the yucky grass he ate?”*
Can he still smell the flowers?”
Can he see where he is?”
DesireDesire
Does he still wish he didn’t have a brother?”*
Does he still want to go home?”*
Does he still hope he gets better at math?”
Does he still wish he didn’t have a brother?”*
Does he still want to go home?”*
Does he still hope he gets better at math?”
EmotionalEmotional
Is still sad because he can’t find his way home?”*
Is still angry at his brother?”*
Still loves his mom?”
Is still scared of the alligator?”
Is still sad because he can’t find his way home?”*
Is still angry at his brother?”*
Still loves his mom?”
Is still scared of the alligator?”
EpistemicEpistemic
Is still thinking about his brother?”*
Still believes he’s smarter than his brother?”*
Knows that he’s not alive?”
Still believes his mom is the nicest grownup?”
Is still thinking about his brother?”*
Still believes he’s smarter than his brother?”*
Knows that he’s not alive?”
Still believes his mom is the nicest grownup?”
Percentage of discontinuity responses by age and question type
Percentage of discontinuity responses by age and question type
0
20
40
60
80
100
Bio Psybio Percep Emo Des Epi
Kind
Late Elem
Adult
Percentage of 5/6-year-olds participants providing
discontinuity responses, by school- and question-type Percentage of 5/6-year-olds participants providing
discontinuity responses, by school- and question-type
0
10
20
30
40
50
60
70
80
90
100
Bio Psybio Per Emo Des Epi
Question Type
% Discontinuity Responses
Religious Secular
Percentage of 8/9-year-olds participants providing discontinuity responses, by school- and question-type
Percentage of 8/9-year-olds participants providing discontinuity responses, by school- and question-type
0
10
20
30
40
50
60
70
80
90
100
Bio Psybio Per Emo Des Epi
Question Type
% Discontinuity Responses
Religious Secular
Percentage of 11/12-year-olds participants providing discontinuity responses, by school- and question typePercentage of 11/12-year-olds participants providing discontinuity responses, by school- and question type
0
10
20
30
40
50
60
70
80
90
100
Bio Psybio Per Emo Des Epi
Question Type
% Discontinuity Responses
Religious Secular
Percentage of participants providing discontinuity responses,
by age and question type Percentage of participants providing discontinuity responses,
by age and question type
0
10
20
30
40
50
60
70
80
90
100
Bio Psybio Per Emo Des Epi
Question Type
% Discontinuity Responses
5/6 y-olds 8/9 y-olds 11/12 y-olds
Inferring communicative intent in the occurrence of random events: Developmental trends (Bering &
Baumann)
Inferring communicative intent in the occurrence of random events: Developmental trends (Bering &
Baumann) Children place hand on one of two boxes to win a prize.
Princess Alice sends “messages” to 3- to 9-year-old children
Picture of Princess Alice falls off wall
Light flicks on and off
Do children change their hands when given a signal
How do they explain the events?
Children place hand on one of two boxes to win a prize.
Princess Alice sends “messages” to 3- to 9-year-old children
Picture of Princess Alice falls off wall
Light flicks on and off
Do children change their hands when given a signal
How do they explain the events?
Behavioral Change. Condition and age group comparison of receptive response (i.e. moved hand to the box opposite the first selection
following the occurrence of either the iconic or ambiguous random event) on at least one unexpected event trial.
Behavioral Change. Condition and age group comparison of receptive response (i.e. moved hand to the box opposite the first selection
following the occurrence of either the iconic or ambiguous random event) on at least one unexpected event trial.
0102030405060708090
3- to 4-year-olds 5- to 6-year-olds 7- to 9-year-olds
Age Group
% Receptive Response
.
Control Experimental
Explanations for EventsExplanations for Events
Declarative agentive (e.g., “Princess Alice did it because she was trying to help me find the ball”)
Intentional agentive (e.g., “Princess Alice did it, but I don’t know why”)
Other (physical, another person, no explanation)
Declarative agentive (e.g., “Princess Alice did it because she was trying to help me find the ball”)
Intentional agentive (e.g., “Princess Alice did it, but I don’t know why”)
Other (physical, another person, no explanation)
Age group comparison of agentive explanatory types.
Age group comparison of agentive explanatory types.
0
10
20
30
40
50
60
70
80
3- to 4-year-olds 5- to 6-year-olds 7- to 9-year-olds
Age Group
% Agentive Type .
No ExplanationIntentional ExplanationDeclarative Explanation
The Serpent’s GiftThe Serpent’s Gift
“But the serpent said to the woman, ‘You will not die. For God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil.’ So . . . she took of its fruit and ate; and she also gave some to her husband, and he ate. Then the eyes of both were opened, and they knew they were naked” (Genesis, 3: 4-7, Revised Standard Version).
“But the serpent said to the woman, ‘You will not die. For God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil.’ So . . . she took of its fruit and ate; and she also gave some to her husband, and he ate. Then the eyes of both were opened, and they knew they were naked” (Genesis, 3: 4-7, Revised Standard Version).
Evolutionary psychology often focuses on the “darker” side of human nature.
Selfish gene perspective With self-consciousness we can also look to “the better
angels of our nature” (Abraham Lincoln, 1961)
Evolutionary psychology often focuses on the “darker” side of human nature.
Selfish gene perspective With self-consciousness we can also look to “the better
angels of our nature” (Abraham Lincoln, 1961)
“There is grandeur in this view of life,with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”
Charles Darwin, The Origins of Species (1859)
“There is grandeur in this view of life,with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.”
Charles Darwin, The Origins of Species (1859)