primate soc psych exam 2

what is the primary goal of evolution?

what is the primary goal of evolution?

to pass on genes and maximize reproductive success

anisogamy

species that have unequal sized gametes (ie human sperm vs egg), often representing each sexes’ parental offspring

is child rearing only seen in female primates?

no, equal male + female parental investment can be observed in tamarins

main difference between the sexes in reproductive fitness maxing strategies

males invest in mating opportunities while females invest in offspring

reproductive variance

the range of reproductive success/amount of offspring of one sex

average reproductive sex across the sexes

reamins similar

the majority of reproductive success in chimpanzees is largely due to what rank(s) of males?

the alpha and beta male

how does dominance influence female chimpanzee reproductive variance?

rank has a much less variable effect on reproductive success - most females are not far off in terms of offspring compared to the alpha female

bateson’s principle

males tend to have far higher reproductive variance than females

what tactics do primates utilize to reduce potential for inbreeding?

• dispersal

  • westermarck effect

westermarck effect

reverse sexual imprinting —> people are less likely to find their relatives attractive than strangers. this extends to unrelated individuals who were raised together

how do males and females differ in reproductive success tactics?

males compete for acess to mates while females prefer to find quality mates

examples of male-male competition

direct competioin, sperm competiotion, and infanticide

direct competition tends to favor

the larger and more physically powerful male

example of primate species that engage in infanticide

langurs

purpose of infanticide

1. to establish the dominance status of a new alpha male

2. to revert females back to reproductive readiness

is infanticide a universal practice?

it is not universal across primates or even in individuals from species who use infanticide

chimpanzee vs. bonobo sexual dimporphism

chimpanzee males and females have a significant size difference while bonobos tend to be the same size regardless of sex

sperm competition

species that rely on viability of their sperm from male to male to outcompete others

how does mating structures of a species relate to testes size?

species with higher rates of monogamy tend to have smaller testes (chimpanzees are fission fusion —> larger testes than polygyny gorillas)

example of males presenting to females

chimpanzee males storm forests and shake trees to exhibit powers

examples of primate species that exhibit parental care

squirell monkeys and titi monkeys

how do lower ranked male baboons increase their reproductive scuccess?

they form close bonds with the females and spend a lot of time with her/her infant, increasing her likelihood of mating with the male after returning to reproductive readiness

cons of obvious female sexual swelling

leads to female monopolization due to short period of reproductive readiness

concealed female sexual swelling example

bonobos often experience sexual swelling even if not ready for reproduction

chimpanzee male mate age preference

old parous/older mothers

agression

conflict between members of the same species

factors that contribute to aggression

• drive

• genes

• learning/upbringing

• models/tv

• frusteration/pain

• alcohol (substances)

  • hormones

konrad lorenz aggression model

we recieve tension from various areas of life that build up until producing aggressive behavior

frans de waal arnhem zoo experiment

found that tighter confines increased chimp aggression excluding acts of severe aggression (ie fights). also found that the amount of submissive behaviors and social grooming increased.

how can chimp group aggression levels change?

via changing living conditions, such as having vocal neighbors from a different group

sapolsky baboon study

• observed a baboon troupe where half of males (who were mostly high ranked) passed away due to ilness. reamining group showed signifigant increase in social grooming, lower male-male interactions + faster integration of new males, and decreased stress and anxiety that continued rto be passed to offspring

alpha male responsibilities

• policing

• peace keeping

• conflict resolution

human impact to primate behavior

1. deforestation

2. disease

3. hunting

4. provisioning

tendency to engage in chimp between group warfare is most influenced by

number and density of chimp males

ultimate hypothesis for aggression

may have developed as a means of driveing dispersal

how does aggression influence contact between individuals?

aggression increases the amount of contact between individuals

how is agression influenced by kinship?

closer relations tend to show more aggression

crowding leads to an increase in what behavior?

grooming (not aggression)

reconciliation

friendly reunion between former opponents shortly after fighting

reconciliation example

stumptails present their back sides to be gromed as a show of trust

chimps put their hands in the mouth of the winner

bonobos use sex

reconciliation benefits

1. lowers risk of revival of conflict

   1. reduces aggression and conflict (individuals and group)

example of anxiety behaviors (macaques)

self-scratching (lowers if reconciliation occurs post conflict)

baboon reconciliation

playing with eachother’s infants (approach + call)

macaque learned reconciliation study

infant rhesus macaques (little reconciliation) were raised with stumptail macaques and eventually began to show reconicilition 2-3X more than average. they kept this behavior even moving back

who will be prioritized for reconciliation? (valuable relationship hypothesis)

kin and important partners

muriquis affiliation

huddling

golden monkey third party reconciliation

male involvement when two females fight leads to much higher post conflict reconciliation levels

male coalitions

male-male social bonds in male dispersal species, often between non-kin. manipulate these social relations for power

gelada male alliances

one dominant male and subordinate(s)

consession model

trading mates for protection

examples of mitagating aggresion

male-infant-male interactions. dominant males usually have favorite infant, and sometimes females will use this to their advantage to invoke male-male reconciliation and interactions between those far in rank

triadic awareness

understanding the relationships between individuals beyonds yourself

bonobo consolation

when needing consolation, usualy seen by screaming, they seek hugs from others

bonobo consolation is primarily given by

top ranked males

chimpanzee reconciliation is typically given by

the lower ranked individuals, especially females (excluding alpha male)

agressive alliance

winner support

defensive alliance

loser support

alpha male responsibilities

1. breaking up fights/consolation

2. peace keeping

3. policing

4. providing resources

5. loser support

6. impartial intervention

differnt types of alphas

1. bully (aggressive towards lower ranks)

2. populist (more positive interactions with lower ranks to recieve support)

requirements for male chimp dominance

1. physical power/intimidation

2. female support

3. male-male alliances

4. generosity

5. divide and rule

capuchin example of inequity aversion

when offered a worse reward than partner (ie grape) they will throw it on the ground/refuse it

advantages of fairness

1. social groups require a lot of cooperation and reciprocity

2. sensitivity may allow for avoidance of future unfair events

most influential factor in inequity aversion

task difficulty

first order inequity aversion

refers to individual themselve being disadvantaged

why would fairness evolve (proximate + ultimate)?

proximate: individuals must be sensitive to fairness in order to avoid being taken advantage of

ultimate: evolved in social species that interact more frequently with non-kin —> larger range of potential partners

when is inequity sensitivity adaptive?

when you have the oppurtunity to select cooperative partners

second order inequity aversion

observing inequity to a partner leading to sharing/equalizing to be fair

chimpanzee social pressure in token exchange

partner who was treated unfairly might show annoyance (ie blowing a raspberry) to pressure partner into prosociality. too much pressure decreases prosocial response.

3rd order inequity aversion

wanting everyone to be treated fairly

what constitutes as economic behavior in primates?

1. trading and bartering

2. “financial” transactions

3. economic biases

relationship between trade and grooming

individuals are more likely to share food with those who groomed them earlier that day

chimpanzee meat sharing behaviors

1. those who hunted are prioritized

2. alpha prioritizes those who may make good alliances + avoids giving food to second rank

requirements of economic behaviors

1. establishing value

2. tracking individual interactions, relationships, ledger, and affinity

3. identify good partners

loss aversion

greater sensitivity to losing what you have then gaining an equivalent amount

reference dependence

purchasing decisions made in reference to initial purchase

dunbar

relationship between cortex ratio and group size

capuchins make good test subjects because

1. they have extrodinarily large brains

2. show cooperative and prosocial behavio

example of presentation (playback) experiments

playing vocal stimulation (ververt monkey alarm calls)

presentation experiments have helped us identify

kin recognition, monitoring relationships, and rank recognition in primates

difficulties of interactive experiments in the wild

1. limited participation

2. one individual often monopolizes testing

3. often a one-shot experiment

Wilson “lethal aggression” paper summary

aimed to determine adaptive explanations of chimpanzee killings. found that most attackers were males + most attacks were intercommunity and that killing rates did not correlate with human impact

human impact hypothesis examples

deforestation, introduced diseases, hunting, providing food

sapolsky pacific baboons

troop with only lower ranked males show far higher levels of grooming and less stress/agression levels that were passed down generations

de waal “crowding”

High population density is not equated with higher levels of violence

de waal “primate aggression”

natural cyclce of agression and reconciliation in chimpanzees that often brings more interactions between agressor and agressee

chapais “rank maintenance”

females are dependent on allies, both within and outside family, for dominance even considering matrilineal inheritance

de waal “animal business”

non-human primates also express cooperation, repayment of favors, and emotional reactions to unfairness

santos & chen “economic behavior”

utilize capuchin token trading to witness similarities between human and animal economics

In Frans de Waal's book, Chimpanzee Politics, which chimp ascended in dominance by continually interfering with dominant male-female interactions?

luit

True or false: Analogy is characterized by convergence and homology is characterized by divergence.

true

agnostic buffering cn be seen in

barbury macaques

Which of the following is the most likely explanation for how chimps track exchanges? 

cumulative affinity

Second order inequality aversion is rare and may only be seen in

humans and great apes

Which of the following statements explain the social intelligence hypothesis?

Social demands produce an increase in brain size & The complexity of primate groups is what led to the development of advanced cognitive abilities

darwin argued that facial expressions

could be cinserved between species, similar to physical traits

nadia kohts

russian primatologist that documented eight distinct emotions in Joni, a chimpanzee, in the 1910’s

fixed action patterns

consistently produced behaviors that are triggered consistently by specific stimuli

Jan Van Hoof

argues that emotions are an example of a fixed action pattern, and that fied action patterns are evolved by natural selection

black crested macaque affiliative communication

use lip smacking to request hugs and smile during these interactions