Study Guide for 2nd Exam

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Human Evolutionary Biology
Human Evolutionary Biology 1329
Richard Wrangham

Study Guide for Exam 2 Theory of mind (TOM): understand others as having goals and intentions and beliefs and desires. evolution of ideas about mind: started with mind-body dualism. mind is from god, does not follow laws of nature, animals do not think. evolved into ape-human continuities. mental evolution. animal cognition is human like. Premack-Woodruff: chimps MAYBE have theory of mine -encultured chimp used symbols. match to sample. half full glass, half full sample. -easy picture matching test: movie with bananas out of reach. choose best solution: passed test. hard picture matching test: (locked in cage, use key) passed! interpreted filmed sequences as representing problems faced by the person. -deception task. bad person might take sadie’s food. good person shows Sadie where fruit is. bad person won’t share food if they find it. deceive the bad person. chimp points to the wrong container. all passed. -chimp needs a human’s help to get food, but human is blindfolded. only one chimp removed blindfold. the rest just dragged. -alternative hypo: chimps learn the strategy that works without understanding it. VIDEO: rhesus monkeys steal grapes when backs are turned. Call & Tomasello: in some ways chimps do. - evidence for TOM in chimpanzees, gaze-following/co-orienting is this: understanding of seeing? (knowing others look because there is something interesting to see) or reflexive orienting (follow changes in body, head, or eye position automatically. -apes follow with gaze even if someone only looks with their eyes. -geometric gaze-following: follow where human is looking even if through barrier. evidence they understand gaze meaning. -representatives of all major groups do it. apes show greater gaze following than monkeys, monkeys than strepsirhines. -chimps understand perspective, do they get needs? -yamamoto: a has to help b get juice. b needs straw, a has objects. cannot see condition: where a can’t see what b needs. and can-see condition, where a can see. -when a could see, gave what needed. when a could not see, it was 50:50. chimps understand needs. -false belief: -child told story of sally’s thing being moved while gone, then asked where will sally look? 3 year olds say the new place, 6 year olds say the old place.6 year old TOM. Cognitive evolution: why and how did cognitive abilities increase --chimps but not monkeys can recognize themselves in mirrors. kids can by 2-3. chimps can solve physical problems and understand properties. and bonobos. ai and ayumu with numeral pressing in right order. CHART: retention of briefly presented numerals. Ayumu outperformed humans and ai. social brain hypothesis -NS favored large brains to negotiate the social arms race. -relying on finding fruit -fruit trees have unpredictable locations -bigger brained primates eat more fruit -negotiating large home ranges, -need a good memory to find food, remember danger sites. big brained have large ranges -extracting difficult food items. -big brained use more tools. high quality hidden foods. -competing in social groups. -social groups have complex relationships that require mental skill. bigger brained larger groups. -neocortex is larger in larger brains. so is selection for neocortex? GRAPH -absolute brain size predicts size of components: % cerebral cortex, total number of neurons, rate of energy use -measure of brain size is not correlated with fruit in diet, or home range size, or foraging complexity, but yes with group size. -larger brained animals play more. -larger brained species: higher ranking less able to pull rank, because successful lower ranking coalitions. -larger brained: more grooming partners. -coalitions, competition, mind reading. other abilities (mirror, tool, ape language) are incidental. variation in social cog ability comes from braings being too costly for some species. -big brains consume a lot of energy. but big brained have same metabolic rate as small brained. larger brains need more energy, dependent on species specific traits: high quality diet (glucose), rich stores of fat (maintain brain w/o food), low energy use by other organs (gut) -primates with high quality diets have larger brains. small guts, large brains. -COOKED FOOD likely how humans fuel brain. Readings: call and tomasello: chimps get goals and intentions and perception and knowledge of others, but not false beliefs. chimps chose food human couldn’t see, chimps followed weird way of turning on light if human hands were not distracted. Campbell and de waal: ingroup-outgroup bias in contagious yawning by chimps supports link to empathy-yawn more in response to ingroup Questions: - Does the chimpanzee have a theory of mind? : yes, in certain ways. understands goals, intention, perception, knowledge/ignorance. but not false beliefs. - What evidence is there that chimpanzees can understand the action of other beings as efforts to achieve specific goals, and why is it disputed? takes food from behind opaque, helps man in video, followed strange way of turning on light. disputed because some think they only understand surface level behavior and behavioral rules. - What do Tomasello and Call mean by ‘behavioral or contextual rules’? set of behaviors learned by observing others in situations and enabling behavioral prediction when the same or a highly similar situation arises. - In what ways do chimpanzees have, and in what ways do they not have, a theory of mind? see above^ - Why is it interesting to conclude that chimpanzees yawn more to in-group than out-group members? shows selective empathy to their own ingroup members than outgroup. care more. - How might you critique the Campbell – de Waal study? yawning not tested in humans, spurious connection between empathy and yawning, social structure. Parenting and Cooperative Infant Care Life history theory -fetus, infant, juv, adolescent, adult, senescent. • - Tradeoffs: -timing, investment, & duration of life stages are necessarily interrelated. -need ENERGY for Maintenance (immune function, metabolism, behavioral activity), Development (growth, maturation, learning), Reproduction (quantity and quality) -stage between development and reproduction overlap. -reproduction vs growth -current reproduction vs. survival -current reproduction vs. condition - Current vs Future reproduction -young, cut down on development to breed. longer future reproduction. -number vs. size of offspring (quantity vs quality) 1 • Parent-offspring conflict - Relatedness -offspring want more attn. than parent can give. -robert trivers: -in promiscuous primate societies, paternal care is rare. mothers bear reproductive burden. infants selected to demand more resources than mother can provide. -mother is equally related to each offspring. infant, mother is related 100% to self, 25-50% to siblings. - Sources of conflict -duration of investment -amount of investment -cooperation directed towards siblings. -under certain conditions, mother will: -reduce physiological investment (miscarriage, milk) -neglect infants (ignore, limit care) -abuse infants (rare) -seen in humans Maternal behavior Mother-Infant Relationship -first social bond. -bowlby: attachment theory. felt safe, play explore, separation anxiety, proximity/security seeking, reunion/maternal response. ^contingencies. mother as secure base and safe haven: maximizes play, exploration, learning, safety, security, survivial. transitional->provisioned food->independent foraging. -humans: breast milk->complementary with safe and adequate foods (formula)->provisioning and foraging • - Mother-infant playing -body contact, body stimulation, object stimulation, face to face, mutual eye contact. object stimulation varies by culture indepependent. PROPORTION OF 10 sec intervals graph? Paternal care • - Among mammals : common in birds, -appears in certain taxa. primates: marmosets, tamarins, titi and saki, gibbons and siamangs, humans. rodents: cali mice and prairie and pine voles, carnivores: wolves, wild dogs, meerkats • - Direct vs indirect paternal care -indirect: predator vigilance, territorial defense -direct: carrying, food sharing -Physiological correlates of paternal behavior Paternal care -hormones: testosterone, prolactin, vasopressin/oxytocin, progesterone, cortisol -PROXIMATE/Mechanistic explanations. -prolactin: secreted by anterior pituitary: in females, it promotes lactation, in males, may be paternal care? -in marmoset, tamarin, titi: fathers more prolactin than nonfathers. not in goeldi’s monkey. -higher prolactin after infant birth: marmoset, goeldi’s, not titi or tamarin. higher prolactin plus infant carrying in marmoset but not others . -trouble of hormonal correlations: carrying could cause prolactin levels, prolactin could cause carrying, or there could be an unknown third factor -testosterone -male mice: precastration, lots of biting, post, very little, T injection: more biting -in golden lion tamarin: low T in birth season, in black tufted ear marmosets: low T during period of infant carrying, males with lowest T carried infant more, marmosets: exposure to pup scent lowers T, cotton top tamarin: multiparous males increased T during pair mate’s pregnancy. -humans evidence -fleming: new fathers and non-fathers exposed to infant cries. fathers who heard cries were more sympathetic, fathers and non-fathers with lower T felt more sympathy and need to respond, and fathers with high prolactin also more alert and responsive -do partnering and fatherhood cause T to decline? GRAPHS I DON’T GET -yes i think -is T lower among fathers providing childcare? yes i think from weird graphs. -fathers have higher prolactin than nonfathers (in study) -PROXIMATE. • - Evolutionary significance (ultimate/functional explanations) -direct genetic benefits: increase survival, increase quality -reduce costs for pair mate: shorted interbirth interval -promote mating opportunities Cooperative care in mammals -appears in certain taxa. marmosets and tamarins and humans and wolves, wild dogs, meerkats -cooperative breeding: a social system in which individuals care for young not their own (alloparenting) -reproducing adults, nonreproducing adults (reproductive suppression), post-reproductive adults, sub-adults/siblings -why? alloparenting is costly. what are the benefits that would have led selection to favor alloparenting? -adaptive hypotheses -1) reproductive competition (imposes costs on infants and mothers) Kidnapping -2) mis-directed maternal attachment (kidnapping/adoption) -3) babysitting (reduces mom’s time/energy on infant care) -inclusive fitness and kin selection: help from parent’s relatives, help from infants relatives -Grandmother hypothesis. adaptive conundrum: human menopause. proposed solution: grandmothers shorted the IBI of their daughters and enhance the survival of their grandchildren enough to outweigh direct fitness benefits from having more children of their own -parenting practice. helps later reproductive success of helpers. -4) reciprocity -5) alloparenting not that costly, reproductive cueing, tradeoff in exchange for larger social group -all species with helpers have faster infant growth and shorter IBI -Case study from human populations: -Hunter Gatherer Aka. subsistence hunter gatherers. nethunting, collecting, moving 8 times a year. egalitarian groups of 25-35. mutualism with ngandu farmers. female based horticulture, nonegaltarian villages. different infant and childrearing practices. Aka infants more frequently in contact with caregiver than ngandu and US allomaternal nursing. weaning: infant initiated 3-4 years. child little fussing. caregiving transition to other adults. Ngandu: 1.5- 2 years, mother initiated, rice and gruel to wean, crying and tantrums, siblings caregiving. Take away: -variation in infant care among individuals, populations, and species. -hormones and behavior are interrelated. -variation reflect life-history tradeoffs, parental experience, evolution, and in humans- culture. Readings: -keller: The Bio-Culture of Parenting: Evidence From Five Cultural Communities --culturally formed parenting stylers during infancy, related to independence and interdependence. -free play mothers and 3 month old in 5 cultures -4 parenting systems: body contact, body stimulation, object stimulartion, and face to face contact. -2 styles (distal and proximal) related to independence and interdependence. -infants participate from birth in sociocultural activities that are committed to cultural goals and values that inform parenting behvaiors --Based on the evidence presented, we relate the faceto-face system and the object stimulation system to independent sociocultural orientations and the body contact system and the body stimulation system to interdependent sociocultural orientations. -body contact and stimulation: interdependence. object stimulation and face to face: independence -2 clusters: greeks and germans one cluster, lower socioeconomic instnother. mothers age at birth earlier. -1 cluster: body contact and body stimulation. indian didn’t have as muct body contact, anemic not that much energy. -parent offspring conflict ^ infants want more energy and investments than a mother wants to give. -primaparous-1 pregnancy -nulliparous: never given birth -multiparous: more than one -distal- independent -proximal: more closely related to center of body, interdependent -zeitgeist: in the spirit of the times, dominant paradigm at that time. -Gettler: Prolactin, Fatherhood, and Reproductive Behavior in Human Males --little known about hormonal architecture of human paternal investment -prolactin important reproductive functions: higher during periods of offspring care -fathers higher than nonfathers. fathers of infants had borderline higher than fathers of older children. -among nonfathers: men with > prolactin had more sexual partners and sexual activity. -prolactin seems to be at odds with testosterone. intro -in fish, PRL necessary for paternal care, and induce paternal care in birds. questions: How does cultural context shape mother –infant interactions? -independence and interdependence. What do you think is meant by vertical cultural transmission? -children taking on cultural aspects from parents and older caregivers. learning from each other is horizontal but starts as vertical. (slang and other stuff added horizontally) How can this be contextualized within the biological framework of parent-offspring conflict? cc allows mother to change amount of investment they have in child Social Learning and Culture -chimps: the most ‘cultural’ NHP. -hand clasp grooming. cultural, but trivial. -species-exclusive culture definition: that complex whole which includes knowledge, belief, art, morals, custom, and any other capabilities and habits acquired by man as a member of society -broader: population level behavior, multigenerational, depends on social learning, explicable only by social learning (not ecological or genetic variation) -Significance of culture: imagine arriving without knowing how to exploit environment. burke and wills: cross Australia. ignored local culture. died. -1) vital for humans: how to process food, identify food, make fire, keep warm -2) nongenetic source of adaptation and behavioral evolution -lamarckian: inheritance of an acquired trait: giraffes thach, neck gets longer, passes that down. DISproven in 19 century. germ plasm theory. inheritance only from eggs and sperm. circumcised men, rats with cut tails. -modern lamark: inheritance of traits without changing DNA. -epigenetics: offspring protein production influenced by methylation of maternal DNA. -high stress infancyhigh stress response (adult) and DNA methylation (on Cytosine) and A) change in protein productionhyperactive stress system and B) offspring DNA is methylated, similar effects -dual inheritance theory/gene-culture coevolution or biocultural evolution. -culture evolves, capacities for culture evolved as adaptations, genes and culture co-evolve -dairying and lactase persistence. -cooking and reduced guts. -adaptive culture and social learning biases -conformity: copy the mean, prestige: copy the high rank, similarity: copy similar individual -3) group shibboleth (group identification system) Types of social learning -places: area copying=local enhancement -behavior of others directs attention to a particular place. adaptive sig: avoid dangerous places, predators, poison, utilize beneficial places, increase foraging gains at fruiting tree -objects: object copying=stimulus enhancement -behavior of others directs attention to a class of objects or things that are important to know about (then learner behaves without copying) adaptive sig: predator recognition, mate copying, food aversions, food preferences. rats smell food on the breath of a rat from same colony and has a strong preference for that food. -milk bottle opening by birds. accelerated speed. not one genius bird plus imitation. several sites of origin. high probability of learning without a model. learn as fast from seeing opened bottle as from seeing conspecific. stimulus enhancement likely, attention drawn to feeding opportunity. -japanese monkey feeding behavior potato washing. no evidence of direct copying. -behavior: behavior copying=imitation -acquiring a topographically novel behavior after seeing another individual use it. birds vocal learning, rare elsewhere. some primates. adaptive sig uncertain. superior learning system? (copy high quality calls?) or incidental consequence of cognitive ability. -imitation reported in captivity, but does it lead to reliable behavior copying? -observational learning: yerkes field station. 2 large social groups. -FS1 15 chimps, FS2, 14. -two traditions pan pipes study. two ways to get food. poke and lift. taught a few from each group one way. other chimps mostly just copied without independent invention. -teaching: private information: active instruction by experienced individuals -Active. coaching like HG. occurs in all human societies. -no firm evidence of primates teaching. nut cracking, not currently credible. -reported for various predators: meerkats convincingly shown. must learn to catch and eat scorpions. helpers provision with dead scorpions, then scorpions with stingers removed, then live as older. -criteria for teaching: A modifies its behavior only in the presence of B. A incurs some cost or does not obtain immediate benefit. B acquires knowledge or learns a skill earlier in life than it would otherwise. • Social learning biases • - Sex-biased social learning -bobo doll experiment. do children copy same sex adult? children see adult models agg or non agg. put in room with nice toys but aren’t allowed to play to promote frustration. children then let alone with bobo doll. -both sexes imitated violent behavior, and tended to imitate bob violent behavior -boys more than girls imitated physical agg of same sex model. girls more than boys imitated verbal agg. -baloon experiment. infants play with balloon. then adult model hits or cradles. then free play with balloon. -boys>girls copy hitting by adult males. babies of both sexes looked at female models more, spent same time cradling before and after, and spent same time hitting before -boys looked at hitting more, and increased hitting time after videos, and hit more when male models hit. -female chimps practice and learn termite fishing faster and more thoroughly than males. adult females obtained more termites per dip. spend more time at termite mound. daughter copy mothers choice of tools. sons do not, they pay less attention. • - Best models for learning -rule: copy the successful. -stickleback fish. 1) copy foraging area of largest individual. who is best model is stable. 2) copy foraging area of those feeding better than self, who is best model changes over time. -primates: what rules do they use to assess who is successful? -BIOL: bonding and identification based observational learning. best models are those with long-term success, regardless of current behavior. -same species. high ranking old, philopatric sex. -testing importance of dominance and philopatry as models: Vervets: 2 ways to open artificial fruit. pull or slide. alpha female and male allowed different ways to open fruit. others watch. one way is blocked. experimental phase: both ways are open. fruits given to group or isolated individuals. copied female more than males. group members pay more attention to and copy more from females than males. alpha females better models than alpha males? -not dominance or success. maybe knowledge of environment. lifetime experience while males immigrate predictions based on vervet study : -naturally occurring traditions based on social learning will be found in comparisons between neighboring groups. -idiosyncratic group traditions should be expressed by members of the philopatric sex. -nut cracking varies among neighboring chimp communities. hammer could be stone or wood. 3 groups. female immigrants adapted to new communities. -do female influence the number of cultural traits in Pan? more than males? -use tools more frequently, learn better than males, emigrate to new community at adolescence. -GRAPHS -tentative evidence. # of traditions across chimp communities varies with # females, does not vary with # of males Social Learning can lead to individual or group effects: -individual differences. -group: shared traits. “culture”: transmitted repeatedly through social or observational learning to become a population level characteristic not through genetics or ecology but through social learning. -do animals have culture? origin of population level difference is normally unknown. must rule out genetic and behavioral adaptation to local context -nut cracking. cultural? pros: limited geographically. young take a long time to learn. females adapt to local style. cons: something special about the local environment? all learn individually? populations without it don’t need it. -capacity for social learning. give nuts and hammer. one knew how to do it and others didn’t until they saw one do it. -pro culture: largely confined to geographical area despite suitable nuts elsewhere. evidence for multiple generations. social learning appears to be involved. social learning is possible. adjacent groups have different behaviors. con: possible ecological differences: different qualities of nut or other foods (changing the economics of nut cracking) -experimental evidence: wild chimps. geo close. similar habitats. negligible genetic differences. one uses sticks to obtain honey, the other no sticks but some leaves. how would chimps from each community access honey when presented in novel way? -matched their group (stick or leaves) when deeper, leaf group didn’t eat honey. -rely on cultural knowledge to solve a novel task. -chimps have culture: population level behavior, multi- generational, depends on social learning, not explicable by individual adaptation. -tools can be useful. nut cracking gets up to 30% calories per month and important during food poor season -fur rubbing? are traditions useful? -primate traditions vary widely -produce much food apparently useless -across populations: no correlation with need with habitat and distribution of tradition complexity is mysterious. -adaptive? traditions can be used adaptively, but there is little indication that the capacity for culture evolved as an adaptive trait Is culture adaptive? -why did culture evolve? -1) adaptive perspective: selective pressurespecific cognitive ability. need adaptive responsessocial traditions. 2) by product perspective. selective pressuregeneral cognitive ability->unselected specific cognitive ability -NHP: culute is byproduct. no teaching, no gene culture coevolution, no cultural norms, no group identifier. humans it is selected for. Readings -sanchez: The impact of early adverse care on HPA axis development:Nonhuman primate models - This review presents supporting evidence that early disruptions in mother–infant relationship in primates, including infant maltreatment, are important risk factors for the development of psychopathology and pathophysiology during childhood and adolescence. Current research in this field is trying to identify important aspects of early adverse experiences such as the timing, frequency, duration, “perceived” intensity of the stressful or traumatic events, the role of social support (e.g., nurturing caregiver) in buffering the deleterious outcomes of early adversity, as well as the role of sex and genetic factors on individual variability in vulnerability. The use of nonhuman primate models of early adverse caregiving is helping to put the pieces of the puzzle together to fully understand the causes and consequences of similar experiences in humans. These models are essential to characterize the time course of biobehavioral alterations throughout development, using prospective, longitudinal studies performed under controlled experimental conditions and using invasive approaches that are unrealistic and unethical when studying human populations. -perry: Social Conventions in Wild White-faced Capuchin Monkeys --five behavioral patterns qualified as social traditions: handsniffling, sucking of body parts, and three types of games. -some conventions independently invented in virtually identical form at multiple sites. -extinction of several conventions observed during course of study, rarely last longer than 10 years. -hypothesized that the monkeys are using these group or clique specific social conventions to test the quality of social relationships --to understand socioecological factors, it is necessary to look beyond great apes. -capuchin monkeys: new world -independently evolved many traits that are present in humans and chimps -large brain-body ratio, omnivorous, extractive foraging, sometimes share food, skilled tool users, nonconceptive sex, alloparenting, lethal agg, complex social relationships -most models of social transmission are about behaviors performed by single individuals that have a clear adaptive function -social conventions are necessarily performed dyadically rather than by single individuals, the role that social conventions play in the behavioral biologu of the animals is different from the role of foraging related behaviors: transmissions different than the more frequently modeled ones. - behavioral tradition: a practice that is relatively long-lasting and shared among members of a group, each new practitioner relying to some extent upon social influence to learn to perform it. Three criteria: -inter-group variation: the behavior in question must be present in at least one social group and absent in at least one group. must be seen at a rate of at least once per 100 hours of observation, and must be performed by at least three individuals. absent: must never have been seen, and observed for at least 250 hours. -expansion: behavior must exhibit an expansion in the number of performers over time (unless all group members perform it) -durability: the behavior must be durable. we arbitrarily coded behaviors as durable if they were observed spanning at least a six month period. Questions: You should be able draw the HPA axis from memory including the structures, hormones, and feedback pathways. Be able to explain (generally) how rodent mothers program their infant HPA axis. What makes Perry et al think that the behavior patterns that they describe should be characterized as behavioral traditions?
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