altruism Flashcards
altruism
an individuals behaviour that benits another’s fitness at self expense
example of an altruistic primate behaviour
vervet monkey s giving predator calls
group selection
wyneed edwards theory 1962; unit of selection is the group
‘whats good for the species is food for the individul’
kin selection
altruism among biological relatives (shared genes= extension of the individual)
example of kin selective behaviour in a primate
marmosets; will ‘wing man’ the more attractive brother as more offspring acan be produced by him
inclusive fitness
an individuals TOTAL fitness measured by direct/indirect fitness effects of an action
direct benefits of inclusive fitness
own reproductive success
indirect benefits of inclusive fitness
the success of a relative= some of YOUR genes keep going
hamiltons rule
degree of relatedness (r)= determines the extent of collaboration
c< bXr
where c= costs of act to individual
b= benefits of act to recipitent
r= degree of relatedness between individuals
reciprocal altruism
form of mutliaims; self-cost beahaviour taken under assumption it will ‘pay off’ with an equally valuable act
multi-level selection
the OVERALL fitness of a group is increased by collaborating altruists:
what needs to happen for multi level selection altruism to work
- each altruist can perform simila acts of altruism
- repeated interactions
- low dispersal rates
- egaliterian social systems
- cheatesr must be punished to enforce altruism as a norm
hare and tan 2013 studied…and found…
bonobos! they are unique apes who prefer interacting with strangers than with own group (more likely to share food) = expand their social network!
summary of altruism
a single altruist must have lower fitness when surrounded by a goup of selfish individuals
BUT
an individual living in a group of altruists has higher fitness than an individual in a group of selfish members
kurland 1977: evidence of japanese macaques
close female kin spend more time together to support each other;
hence groom each other more and fight less
vervet monkeys and kin selection example
response faster to calls of kin in fights and especially to kin who recently groomed them
chimp society kin selection
male ‘brother’ bands
male rhesus monkey kin selection
natal dispersal occur; brothers tend to stay togther more and support rank rising
alianceses more likely and more mating sharing
alloparenting; benefits?
group parenting and cooperative breeding:
- allows for children to slowly development= leads to larger brains
- mothers conserve energy
- increased predator protection
- increased access to resources
critique of group selection
selfish would outcompete altruists faster as they would have a higher alturistic effect
who proposed the idea of multi-level selection
sober 1993
sloan wilson 1997
misplaced parent hypothesis
by Sarah Hrdy:
cute helpless kids give signals that attract adults to care for it (hence altricial infant species tend to have cooperative behaviour)
when might parents help a kin
when no self0serving option is availiable (only when excess food)
when there is a dominance structure (subordinates care for dominants like in meerkats)
psedupregnancies
subordinate allomothers have fake preganancies to provide milk for dominant mother (like in meer kats)
advantages of allomothering for a mom
parents trust others with kids= conserve her energy, improve nutrition and stay safe from predators
how does allomothering increase the lifetime success of a mother
allows for LIFETIME reproductive success to increase;
- earlier weaning
- more time for sex
- better resources/nutrient access
cognition aspect of allmothers?
theory of mind; emphaethical intution of mental state of others= henc elikliehood to help higher
examples of allomothering: hanuman langur monkeys
matrilliean, flexible dominance systems that allow for temporary infant handling
> > 50% of primates tolerate allomothers as a result
examples of allomothering: humans
hunter-gatehres hold new borns
examples of allomothering: colobine monkeys
reduced intragroup feeding competition–> changes dominance hierarchy as benefits are gained b carrying communtally to individual fitness
cercopithecines in contrast are more possesive of offspring
who studied allomothering in colobine monkeys
mckenna 1979
andreas paul studied….. and found….
infant handling in primates:
- -> females are INTERESTED in babies
- -> species with egalitarian domiannce systems are more relaxed about allomothering
- species with nepotlistics hierarchical societies have lower maternal tolerance
barbary macaques and allomothering
are polygynadrous, male dispersed, female philopatries; but still NICER with each other
so more infant handling despite being cercopithecines:
- 20% infant handling by others in a day
red colobus and allomothering
no infant handling in red colobus; yes infant handling in black and white colobus (variation)
ESS
evolutionary stable strategy in prissoners dilemna
tit for tat strategy
in game theory; if one person cooperates the other shoudl too and vice verca
relatedness threhold for altruism affects..
if kins fail to recognize each other= cant benefit inclusive fitness from preferential treatment
how do kins recognize each other?
- phenotypic matching
- olfactory/visual cues
- familitarty
- learned behaviour
- socialization
- age
cheney-seyqorth studied… and found…
vervet responses to recordings of kin/dominant group members=
found that rank/kin determine the level of concern/response of the subject to the call
how do rhesus macaques rcognize kin
age similiatiries
3 important components of an alliance to work
conflict resolution
cooperation
maintaining the relationship (sociality and cognition)
examples of perimates that identity kin/non kin in hierarchies
vervety monkeys
baboons
macaques
how do primates identify allies
kin/vs non kin
rank
who recentl groomed you
partners (grooming or sexual)
what do hr macaques do in relationships
try to maintain them
why is there greater social symmetry in chimps
as HR chimps try to maintain relationships also in subordinate chimps to maintain their own dominance but also still appease the subordinates
four steps that might happen when conflict breaks out
- tolerance
- aggression
- avoidance
- reconclliation
(relational model dewaal 1990)
kin biases in behaviour
- social grooming more common among kin
- primates form coalitions with close kin
- kin support affects social structure and is used as a reproductive strategy
- kin selection important in cooperative breind gsystems
rober trivers; conditions for resicoproal altruism
- frequent interaction
- ability to track support given
- ability to reciportate similar support
robin dunbar; function of grooming
establish sociality
dewaal; function of grooming
minimize aggresion and factiliate reconciliation after conflict
how does kin relationshisp affect social structures in baboons
maternal rank can be transfeered in kenyan baboons
matrillines and kins
maternal kin cna occupy rank of moms
ranking within matrrilines
moms> daughters (older siblings< younger siblings)
genetic chimersim function
increases paterntity certaintiy in habitual twining primates, like marmosets, to allow for two parents to ‘share’ children
when does kinship not predict affliation (example)
unrelated male savananna baboons form affliations
kin based coalitions; when?
during dispersal (ring tailed lemurs)
dispersals in males; where do they enter the hierarch
at the bottom= as they grow older and mature (physically and socially) they rise in ranks
where are polyspecific common
in fragmented habitats where its hard to find conspecicis
benefits of polyspceific associatiosn
- foraging
1. predadtor protection (detection, defence, deterrance and dilustion by safety in numbers; herd)
