Psych Exam 1

• What ‘ultimate’ explanations were proposed for infanticide in male langurs? Which explanation appears to have the most support?  

• Social pathology hypothesis- population density stimulates abnormal behavior 

• Population regulation hypothesis- doing it for the good of the group 

• Sexual competition hypothesis- males kill the young of the females they are trying to mate with so they can have access to the females sooner: similar thing goes for females too 

  • Sexual competition hypothesis seems to have the most support  

• Table 1 provides a useful review of ultimate vs. proximate explanations.  

• Proximate causes 

• Genetic-developmental mechanisms  

• Effects of heredity on behavior  

• Gene-environment interactions underlying the development of sensory motor mechanisms 

• Sensory motor mechanisms 

• Nervous systems for the detection of environmental stimuli  

• Hormone systems for adjusting responsiveness to environmental stimuli  

• Skeletal muscular systems for carrying out a response 

• Ultimate causes 

• Historical pathways leading to a current behavior  

• Events occurring over evolutions from the origin of the trait to the present  

Selective processes shaping the history of a behavioral trait  

• Past and current usefulness of the behavior in reproductive terms 

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• What is group selection?  

• Group selection may also be defined as selection in which traits evolve according to the fitness (survival and reproductive success) of groups or, mathematically, as selection in which overall group fitness is higher or lower than the mean of the individual members' fitness values 

  • This doesn’t actually happen bc the selfless genes die out and selfish take over 

• What are Darwinian puzzles? 

• Darwinian puzzle is a trait that appears to reduce the fitness of individuals that possess it. Such traits attract the attention of evolutionary biologists. 

• Constrained product of the process of evolutionary change which requires modifications on top of what has already happened 

• Trait evolved under conditions that no longer exist  

• The trait develops as a maladaptive side effect of an otherwise adaptive proximate mechanism one that generally causes an adaptive outcome  

• Gene flow from the populations subject to different selection pressures prevents members of a local population from evolving the optimal trait for local conditions  

• The trait can't be perfectly designed for 1 particular task since it or its underlying structures are involved in more than 1 activity requiring compromises in its sustainability for any one task  

  • The trait is the constrained product of previous selection in which the already existing attributes of the organism limited what changes could occur in the past 

• What is functional flexibility?  

• Functional flexibility, such that the intensity of responses varies based on the costs and benefits of disease avoidance in a given context 

• What’s the relationship between the biological immune system & the BIS? 

• Operate in a complimentary manner  

  • Disgust and biological immune system activation may co occur  

• What is the domain specific theory of the mind? How does this apply to similarities in mate preferences for gay & straight men? 

• Domain specificity is a theoretical position in cognitive science (especially modern cognitive development) that argues that many aspects of cognition are supported by specialized, presumably evolutionarily specified, learning devices. 

• Heterosexual men are interested in younger women bc of fertility 

• Women like older men bc wealth status and other advantages 

• Homo and heterosexual men are both more proactive when it comes to seeking out potential partners 

• Same with older homosexual men liking younger men  

• However younger gay guys no like older men young men like young men 

  • Homosexual men and heterosexual men have same mating preferences besides the sex of the person 

•  What’s a sub-self? What adaptive problem is each designed to solve?   

• Subselves in your head which each one specialized for a different thing 

• The team player 

• Deals with friendships and the cost of those  

• The go-getter 

• Manages problems and opportunities related to status 

• The night watchman 

• Manages problems and opportunities linked to self protection  

• The compulsive  

• In charge of avoiding disease 

• The swinging single  

n charge of getting mates 

• The good spouse  

• In charge of keeping mates 

• The parent 

• At any given moment only one subselve is in charge  

• Some have compatible goals and some opposite goals 

  • Designed to solve evolutionary problems  

• How do we functionally project emotions based on others’ gender/group membership?  

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• Functional projection: projecting an emotion onto a person   

• Think men are more angry  

  • Females more happy

• How does Maslow’s hierarchy of human motives differ from the updated hierarchy of fundamental human motives?   

• Maslow never mentioned sex or reproduction this does  

• Maslow's top of the pyramid shows a disconnect from biology: the bio stuff at the bottom and the more intellectual stuff at the top not like this with other  

• 3 differences between the new one and the old one  

• Self actualization is not at the top of the new pyramid  

• 3 new motivations at the top of the pyramid all linked to reproduction  

  • The goals in the new one overlap with each other as opposed to being stacked one ontop of each other  

• genetic drift,

• which is defined as random changes in the genetic makeup of a population. Random changes come about through several processes, including mutation (a random hereditary change in the DNA), founder effects, and genetic bottlenecks 

• Founder effect

• occur when a small portion of a population establishes a new colony and the founders of the new colony are not genetically representative of the original population for example, that the 200 colonizers who migrate to a new island happen by chance to include an unusually large number of redheads. As the population on the island grows, say, to 2,000 people, it will contain a larger proportion of redheads than did the original population from which the colonizers came. Thus, founder efects can produce evolutionary change—in this example, an increase in genes coding for red hair. 

• genetic bottlenecks,

• which happen when a population shrinks, perhaps owing to a random catastrophe such as an earthquake. The survivors of the random catastrophe carry only a subset of the genes of the original population 

• What criteria should we consider when invoking the concept of adaptation?  

• Adaptation these things must be true: reliability, efficiency, and economy 

  • Does the mechanism regularly develop in most or all members of the species across all “normal” environments and perform dependably in the contexts in which it is designed to function (reliability)? Does the mechanism solve a particular adaptive problem well and efectively (efciency)? Does the mechanism solve the adaptive problem without extorting huge costs from the organism (economy)? 

• What’s the environment of evolutionary adaptedness (or EEA)?  

• environment of evolutionary adaptedness, or EEA, refers to the statistical composite of selection pressures that occurred during an adaptation’s period of evolution responsible for producing the adaptation (Tooby & Cosmides, 1992). Stated diferently, the EEA for each adaptation refers to the selection forces, or adaptive problems, that were responsible for shaping it over deep evolutionary time. The EEA for the eye, for example, refers to the specifc selection pressures that fashioned each of the components of the visual system over hundreds of millions of years. The EEA for bipedal locomotion involves selection pressures on a shorter timescale, going back roughly 4.4 million years. The key point is that the EEA does not refer to a specifc time or place but rather to the selection forces that are responsible for shaping adaptations. Therefore, each adaptation has its own unique EEA 

• What’s the hypothesized reason for the gender difference in disgust? 

• Buss females have higher disgust sensitivity bc they looked over kids so it needs to be higher to help facilitate this and protect their weaker immune system 

•  What’s the cooking hypothesis?  

• the invention of fire and the ability to cook provided the key evolutionary impetus for the evolution of extraordinarily large human brains. 

  • Evidence supporting Wrangham’s cooking hypothesis includes the following: (1) cooking food provides a predictable increase in its net energy value; (2) cooking renders food more easily digestible; (3) cooking is a human universal; (4) the human brain requires a tremendous number of calories to function, and fbrous fruits and other raw foods rarely can provide enough; and (5) on exclusively raw-food diets, humans fare poorly, and among women, many lose the ability to reproduce 

• Why do plants produce toxins?  

• To protect themselves from predators 

• What is the antimicrobial hypothesis? What evidence supports this hypothesis?   

• antimicrobial hypothesis, spices kill or inhibit the growth of microorganisms and prevent the production of toxins in the foods we eat and so help humans to solve a critical problem of survival: avoiding being made ill or poisoned by the foods we eat 

  • First, of the 30 spices for which we have solid data, all killed many of the species of foodborne bacteria on which they were tested. Can you guess which spices are most powerful in killing bacteria? They are onion, garlic, allspice, and oregano. Second, more spices, and more potent spices, tend to be used in hotter climates, where unrefrigerated food spoils more quickly, promoting the rapid proliferation of dangerous microorganisms. In the hot climate of India, for example, the typical meat dish recipe calls for nine spices, whereas in the colder climate of Norway, fewer than two spices are used per meat dish on average. Third, more spices tend to be used in meat dishes than in vegetable dishes (Sherman & Hash, 2001). This is presumably because dangerous microorganisms proliferate more on unrefrigerated meat; dead plants, in contrast, contain their own physical and chemical defenses and so are better protected from bacterial invasion. In short, the use of spices in foods is one means that humans have used to combat the dangers carried on the foods we eat 

• What is the show-off / provisioning hypothesis?  

• show-of hypothesis (Hawkes, 1991). Hawkes suggests that women would prefer to have neighbors who are showofs—men who go for the rare but valuable bonanzas of meat—because they beneft by gaining a portion of it. If women beneft from these gifts, especially in times of shortage, then it would be to their advantage to reward men who pursue the show-of strategy. They could give such hunters favorable treatment, such as siding with them in times of dispute, providing health care to their children, and ofering sexual favors 

  • Men pursuing the risky hunting strategy would therefore beneft in several ways. By gaining increased sexual access to women, they increase their odds of fathering more children. The favored treatment of their children from neighbors increases the survival and possible reproductive success of those children 

• What is the Savannah hypothesis (landscape preferences)?    

• savanna hypothesis of habitat preferences: selection has favored preferences, motivations, and decision rules to explore and settle in environments abundant with the resources needed to sustain life while simultaneously avoiding environments lacking resources and posing risks to survival. The savanna of Africa, widely believed to be the site in which humans originated, fulflls these requirements. 

•  How does the process of evolution by natural selection work?   

• Natural selection: process by which organisms experience differential reproductive success (# of offspring compared to competitors) based on some component of their phenotype (any observable aspect of the organism)  

• Phenotype ex: morphology (pointed or flat ears in cat), cognitive systems (humans seeing snakes in bottom of vision), behavior (stalking in cats) 

• In other words... 

• More successful phenotypes -> more common in next generation  

• Across many generations, species come to resemble this phenotype (evolution) 

  • Change occurs across generations due to some variants dying out: it does not happen within the individual 

3 necessary conditions for natural selection:  

 

• Variation: organisms differ in some aspect of their phenotype  

• Inheritance: phenotypic variations must be heritable  

  • Differential reproduction: some organisms reproduce more than others due to difference in their phenotypes  

• Know difference between proximate / ultimate explanations & the two categories of ultimate explanations.  

• Proximate (how/what): immediate physiological/environmental causes (mechanistic) and developmental experiences (ontogenetic)  

• Mechanisms as how things work and exposure things and immediate physiological organism  

• Ex you see a black bear evoke a fight or flight response  

• Ultimate (why): evolutionary history (phylogenetic) and adaptive significance  

• What's the function (purpose) of the behavior? 

• Fight or flight response in response to bear is to save your life  

Does it help solve some adaptive challenge? 

• What is an adaptation? How is it defined? 

• Adaptations: reliably developing characteristics that solve fitness-relevant problems 

• Ex umbilical cord  

• Adaptations are identified by testing for functionality 

  • Is the trait/behavior an improbably well suited solution to the specified adaptive problem? 

• What is a byproduct? 

• By products- don't solve fitness-relevant problems, but are linked to adaptations  

  • Ex: having a belly button  (by product of the umbilical cord) 

• What is noise? 

• Noise- trivial differences introduced via genetic mutations: no impact on fitness 

  • Ex: why everyone's belly button looks different 

• What is an adaptive problem / selection pressure?   

• Adaptive problems: challenges that must be dealt with to successfully survive and reproduce (aka selection pressure) 

• What are the two approaches to hypothesis formation in EP? 

• 1 theory driven strategy (top down) 

• 2 observation driven strategy (bottom up) 

• 1 theory driven strategy (top down) 

• Derive hypothesis from existing theory -> test predictions based on hypothesis -> evaluate whether results confirm previous predictions  

• Ex: with parental investment theory: the sex investing more in offspring is choosier about sexual partners  

• Step 1: derive hypothesis from existing theory 

• Hypothesis: females (vs males) humans will be choosier about short-term sex partners  

• Step 2: test predictions based on hypothesis  

• 1 of 3 invitations: I've seen you around campus and you're cute 

• Go out with me tonight? 

• Come over to my apartment? 

• Go to bed with me?  

• Step 3: evaluate if results support hypothesis  

• Go out with me- 50% of men and women said yes to the date  

• No sex difference  

• As it gets closer to the possibility of sex being offered more men say yes just under 80% say ya I'll sleep with you to someone  

• Very few said yes to apartment almost no women say yes to go to bed  

  • Huge sex difference between men and women with this 

2 observation driven strategy (bottom up) 

• Derive hypothesis from observation -> test predictions based on hypothesis -> evaluate whether results confirm predictions 

• Classic adaptationist approach  

• Ex with incest disgust  

• Step 1 observation -> derive a hypothesis 

• Observation: cross cultural ubiquity of incest taboos/ disgust (especially among close relatives)  

• In great tits as relatedness increases there is inbreeding depression (more issues with fertility and more difficult for offspring to be born and more likely the offspring will have development and fertility issues)  

• As levels of relatedness increase the more eggs that fail to hatch 

• As inbreeding coefficient increases more issues with fertility/eggs failing to hatch   

• is sexual desensitization to those with increased relatedness to avoid inbreeding depression? 

• Hypothesis: more shared genes = more incest disgust  

• Increased disgust for closer vs more distant relatives  

• Step 2: test predictions  

• Give people stories to read and think about  

• Step 3: evaluate whether results confirm predictions   

• Hypothesis was true  

• More closer related = more incest disgust  

• However throughout most of history it was impossible to directly measure degrees of biological relatedness  

• Step 1: observation -> derive a hypothesis  

• Hypothesis: cues to genetic relatedness (reliably occurring throughout evolutionary history) -> sexual desensitization  

• Maternal perinatal association: seeing mother caring for an infant 

• One of the strongest cues for sexual desensitization 

• This shows that this kid is related to you and not to get with them  

• This was supported it was a cue leading to this 

  • Westermarck effect: 1 cue reliably occurring throughout human history leading to sexual desensitization is co residence living together cues genetic relatedness: early childhood co-residence (even in unrelated peers): 0-6 is time when it happens  

• What does ‘fitness’ mean from an evolutionary perspective?  

• Average reproductive success of a phenotype when interacting with a recurring feature of the environment  

• Average- averaged across all organisms with phenotype  

• Recurring feature- aspect of environment that is consistent across generations  

• Fitness= relative genetic contributions to future generation  

• Reflects match between the phenotype and the environment 

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• What is sexual selection theory?  

 

• Theory of sexual selection:  

• Traits that facilitate mating success will be preferentially passed down to future generations  

  • Sexual selection selects for traits that provide a mating advantage by increasing success with... 

• What are the two processes of sexual selection? Be able to pick out examples.  

• Intrasexual selection: competition between members of the same sex in contests with direct or indirect implications for mating success  

• Physical size, armaments (antlers or horns), aggressive behaviors (male deer fighting for the female) 

• Give example of a trait and ask what is this on test  

• Intersexual selection (preferential mate choice): effort to increase likelihood of being chosen as a mate by members of opposite sex  

  • Adornments (peacock feather) gifts (nuptial gifts usually the male gives gifts to the female then mating occurs) displays (bird dances) 

•  What are three ways natural selection changes populations? 

  •  

•  Directional selection: selection against one extreme and selection for 1 extreme 

• With the moths either for or against them 

• Disruptive selection: selection against the intermediate phenotype 

• Disrupting the middle 

• Stabilizing selection: selection against both extremes (selection toward the middle) 

• Why hasn’t sickle cell anemia been selected out of the population? 

• Sickle cell anemia 

• Recessive 80% of homozygotes die without reproducing  

• It should die out but in some pop 10% frequency and gene frequency stable  

• Malaria: deadliest disease in history currently killing 3.5 million people per year  

  • Heterozygous advantage: increased resistance to malaria in heterozygotes (1 sickle cell gene and 1 normal gene) 

• What is inbreeding depression? What adaptations help avoid inbreeding depression?    

• In great tits as relatedness increases there is inbreeding depression (more issues with fertility and more difficult for offspring to be born and more likely the offspring will have development and fertility issues)  

• As levels of relatedness increase the more eggs that fail to hatch 

• As inbreeding coefficient increases more issues with fertility/eggs failing to hatch   

• Maternal perinatal association: seeing mother caring for an infant 

• One of the strongest cues for sexual desensitization 

• This shows that this kid is related to you and not to get with them  

• This was supported it was a cue leading to this  

  • Westermarck effect: 1 cue reliably occurring throughout human history leading to sexual desensitization is co residence living together cues genetic relatedness: early childhood co-residence (even in unrelated peers): 0-6 is time when it happens 

• What is parental investment theory & what does it predict?  

• parental investment theory: the sex investing more in offspring is choosier about sexual partners   

  • Predicts that women will be choosier about short and long term sexual partners

•  What adaptive problem does pregnancy sickness help solve? What evidence supports the evolutionary view on pregnancy sickness?   

• Why does morning sickness (pregnancy sickness) exist? 

• Proximate: nausea, the feeling of nausea is driven by human chorionic gonadotropin (HCG) produced by the baby  

• Ultimate: does morning sickness provide a survival advantage to fetus?  

• It provides a signal that you are pregnant and then you don't do things to damage the fetus  

• Does pregnancy sickness decrease fetal exposure to teratogens (things that hurt the fetus)?  

• Teratogens: cause defects in developing embryos/ fetuses  

• Produced by:  

• Plants (to avoid predation) 

• Bacteria  

• Parasites in animal products  

• Most damaging during 1^st trimester  

• Decreased morning sickness after 1^st trimester (sensitive period for fetal organ development) 

• Pregnancy sickness is highest in 1^st trimester when teratogens is most damaging then after that it decreases 

• It is highest around week 10 when it would be most damaging if something happened to the fetus  

• Increased toxic food= increased aversions  

• Highest aversion for meat bc of bacteria  

• Foods less likely to have parasites more cravings more cravings with safer foods  

• Ex sweets fruits grains  

• Having more Pregnancy sickness (vs none) associated with decreased risk of miscarriage 

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1st myth of EP humans are

• humans are end product or pinnacle of evolution  

• Humans are not at the top  

• Evolution is a bush not a ladder  

• No such thing as a "more evolved" species (or groups of humans) 

  • Humans did not come from monkeys but we share a common ancestor  

2nd myth evolution acts

• Evolution acts for the good of the species (group selection) 

• Traits are not selected to benefit the species as a whole  

• Good of the species behaviors no make sense bc some individuals who act selfishly will over take the population vs those who act nonselfishly  

• Selfless behavior gets bred out of the population  

• "good of the species" genes lose out to "selfish" genes 

  • "good of the species" behavior better explained by selfish fitness consequences 

  • If bird minimizes number of eggs laid in a drought then it could be doing it bc it itself wasn't in good enough condition to have more 

3rd ep justifies

• Ep justifies reprehensible behaviors (ex violence) bc it is saying its natural 

• Based on naturalistic fallacy: if it's natural (evolved) its ok (or even good) 

• Ex in some cases infanticide is adaptive but if fall into naturalistic fallacy then they say its ok  

• Pointing out function/origin of behavior is not justification  

  • Information= description/ explanation: NEVER justification  

4th i don’t

• I don't want it to be natural (since it's offensive/undesirable) so it can't be natural  

• Based on moralistic fallacy: I don't wanna believe in this so its not true  

• Ex: lipstick effect (women spend more on cosmetics during recessions) people claim it's not true bc they don't want to believe it  

  • It's very easy to discount info we don't like but when evaluating truth/veracity, we should look at the evidence 

5th evolution and

1. Evolution and religious beliefs are incompatible  

1. NOT TRUE! 

2. Evolution by natural selection = set of principles explaining why we do the things we do  

3. Religion= principles that tell us how we should lead our lives  

6th myth damming

2. Damming Determinism: EP claims humans behavior is a) soley genetically determined and therefore b) can't be changed  

4. NOT TRUE  

5. Genes build bodies/brains in ways that predispose behavior... but the environment (prenatal, social, physical) influences predispositions at every step of development  

6. Knowledge of predispositions creates the possibility of change  

7th myth of

3. Myth of Optimal Design: selections grants us whatever features we need  

7. NOT TRUE! 

8. Trade-offs are unavoidable (human infant body weight) and evolutionary time lags  

9. Selection for better traits not perfect ones  

8th myth of

4. Myth of Reproductive Motivation: evolutionary theory implies conscious motivation to maximize gene reproduction  

10. Fitness doesn't always mean having the most offspring  

5. In some cases it's better to have fewer offspring and invest more in those offspring  

11. Selection shaped characteristics that helped solve specific adaptive problems inherent in survival and reproduction 

6. Liking sweet tastes, liking sex, attraction to opposite sex 

12. No conscious motivation to maximize gene reproduction needed! 

13. These tendencies occur on average (not 100%) 

7. Not everyone likes sex, is attracted to the opposite sex etc 

• Evolved Psychological Mechanisms (EPMs) 

• Specific psychological features shaped by selection to solve specific adaptive problem  

• Fit like a lock and key with specific adaptive problems  

  • Ex fear of heights -> there to serve a purpose that you don't fall down and hurt yourself 

Mineka's monkeys (Capuchins) and fear response  

• Monkeys don't like snakes  

• Show monkeys a video of monkey encountering a snake  

• Video monkey either reacted in 1 of 2 ways either stay calm and chill or freak out  

• Then show the monkey a toy snake  

• Ones that saw the video with the monkey not fearing the snake didn't freak out no fear 

• But if say video with fear it reacted with fear 

• Ruled out observational learning by showing them a flower (not a survival threat) and monkey on video either reacts with fear or no fear 

• If saw video with no fear react with no fear 

• If saw video where it react with fear exhibited no fear 

  • When it comes to things that don't show a survival threat they aren't afraid you can't condition fear to things that aren't survival threat 

EPMs can produce tremendous behavioral flexibility...  

• Computations vary by environmental and individual factors  

• Adaptive problem: need calories (cued by hunger) 

• In humans:  

• Feces (some undigested nutrients lots of pathogens) -> computation: choose nutritious options and compare alternatives -> no way  

• In rabbits  

  • Feces (lots of undigested nutrients some pathogens) -> choose nutritious option and compare alternatives -> might as well 

• Garcia Effect: Conditioned Taste Aversion: (defies laws of classical conditioning)  

• Discovered this in rats  

• Have rats drink sweetened water (CS) 

• Then expose the rats to radiation and they get nausea (US)  

• Then when rats reexposed they won't drink the sweet water (CR) 

  • Very specific to the aversions it incurs it is only through nausea that the rats won't eat the food again 

• How can evolutionary time lags lead us to do maladaptive things?  

• Natural selection constructs adaptions very slowly  

• Humans spent the last ~2 million years in small hunter-gatherer groups, only transitioning to modern agricultural civilizations in the last 10,000 yrs 

• Humans not always well adapted to the modern world  

• Ex humans crave sweet and fatty foods bc in the past help you gain weight to survive but now this craving can be bad for your help bc eat too much of it  

• Ex fear we have fears of spiders and snakes bc evolutionary good for it but now fear isn't always necessary 

  • Evolutionary mismatch- past vs today's society in terms of adaptive behaviors and how the past isn't always cutting it for today 

• What adaptations help guide us toward safe & healthy food options? How are our food preferences functionally flexible?   

• Food preferences promote adaptive food selection  

• Sweet (and fatty): adaptive benefit -> safe and calorically dense 

• Better spatial memory for high calorie food  

• Done with study at farmer's market and people remembered location of sweets better than other food  

  • Tested before people ask their preferences for whatever flavor/tastes and then after they eat the preference for most food decreases expect for sweet still the same: why you always will eat dessert   

• Dietary diversity:

• adaptive benefit -> maximize nutrients, minimize toxins  

• Preference for a diversity of foods/tastes  

• People eat more when given a variety of food sources  

  • Why people eat more at buffets vs 1 plate of things 

• Protein sickness (rabbit sickness):

• people can't live on lean meat alone (it doesn't have enough fat for you to survive)  

• Limited amount of lean protein safely consumed: ~50% of daily caloric need  

  • Expect there to be a limitation point for protein consuming: proteins fill you up faster so then you eat less  

• Sensory specific satiety:

• declining satisfaction (and satiation) for previously eaten food  

• Exposure to new flavor/food renew appetite 

 

• What’s the omnivore’s dilemma? Know research presented on this.  

• Omnivore's dilemma 

• Plant threats: toxins (detectable via taste) and physical defenses (ex thorns visually detectable)  

• Meat threats: pathogens (difficult to detect and dangerous) 

• Functionally specialized conditioning: greater pathogen threat posed by meats -> more readily forming associations between meat and pathogens  

• Omnivore's dilemma: experimental procedure  

• Sham "similarity" rating task  

• 3 target image groups  

• Meats veggies beverages  

• One group paired with pathogen cue  

• Burger paired with vomit  

• One group paired with neutral cue  

• Burger and then building 

• Significant diff between taste, willingness to eat it, willingness to buy , and like between pathogens and neutral for meat  

• Provide evidence of specialized learning mechanism  

• Plant and beverage no difference 

 

  Evolved navigation theory: 

perceptual biases reflect navigational costs 

• Environmental vertical illusions: 

• overestimate vertical but not horizontal distances (51% overestimation) 

  • When put a bus on its side it would be like a 5 story building 

• Descent illusion: 

• overestimate increase when at the top of something vs at the bottom  

• Think you are higher up when on top of something  

• Degree of bias reflects beliefs about costs and likelihood of falling  

  • People who are afraid of heights show a more overestimation 

• Know research presented about infants’ behaviors towards plants vs. other objects.  

• Plant's produce toxins to avoid being eaten (think bio 131) 

• Given high costs of trial and error learning infants should have mechanisms to allow them to determine what plants are edible  

• 18 month old infants try to see if they differential id plants as a food source: humans should be faster to id a plant as a source of food vs something that looks like a plant vs not  

• Infant sees person put fruit from plant in their mouth or behind their ear did same thing with the artifact 

• For the food behind the ear there is not a significant choice between plant vs artifact  

• When they look at the in the mouth action they chose the plant more when it is the plant option and in the mouth  

  • When infants shown plants vs other objects infants look more frequently to the adults for advice 

• Know research presented on sex differences in visual-spatial strengths & info. presented in class / readings on man the hunter / women the gatherer hypothesis.   

• Thinking critically about sexual division of labor  

• Hunting and gathering = both important  

• In 179 hunter-gather societies  

• Men hunt alone: 166 

• Female main gatherers: 2/3 of societies  

• Men and females hunt: 13  

• General sex differences in food acquisition:  

• Female reliable food : increased consistent  

• Men: high risk, high reward foods: increased variable  

• Why the sexual divisions of labor? 

• Childcare constraints  

• Spatiotemporal variation of different food sources  

• Hard to track prey far away from camp and don't have lot of time to do so 

• Need for diverse macronutrients from mutually exclusive food sources  

• Extensive period of skill-dependent learning time (becoming proficient at hunting takes time) 

  • A sex differentiated comparative advantage in tasks  

• Is there a male advantage in spatial navigation? 

• Mental rotation tasks: m>f  

• Medium-large effect sizes (male advantage but still a lot of overlap) 

• Spatial navigation tasks: m>f (d=.34) 

• In novel environments (put in the middle of the wilderness and have to get back to camp) M explore more (& revisit less) than females... 

  • Men better spatial navigation  

• Is there a female advantage in specific spatial skills? 

• Object location/ object identity memory tasks: F > M (d=~.20) 

• Locating newly learned food locations in a farmers market: F>M (9% advantage) 

• Mushroom gathering task  

• Females more efficient  

  • M expend more energy 

• Summary of food acquisition  

• Food preferences and aversions -> adaptive food selection  

• But evolutionary mismatch  

• Sweet taste used to help us make adaptive food choices but today eating sweet tasting antifreeze then you die  

• Preferences = functionally flexible  

  • Slight sex differences in cognitive abilities facilitate differential success in hunting/gathering 

smoke detector principle

• Smoke detector principle:  

• Based on costs of false positive (you think that it's the deadly snake but it's not) vs false negative errors (you think that it is the safe snake but it is actually the deadly snake) 

• Err on side of the least costly error (bias towards false positive) especially when self-protection is salient 

• Which is less costly? 

• Assume all snakes are poisonous  

• Assume all snakes are safe  

• Same costs for both  

  • Least costly: assuming all snakes are poisonous! 

smoke detector principle and people

• When people asked to imagine an:  

• Angry face = imagined male face 

• Happy face = imagined female face  

• Happiness identified quicker on F faces  

• Anger identified quicker on M faces  

• In gender neutral faces:  

• Angry faces identified as male  

• Happy faces identified as female  

• But what function does this serve? 

• Who is more able to inflict physical damage? (men biologically speaking) 

• Judging presence of anger on M faces 

• Costs of false negatives higher -> bias towards false positives  

• Smoke detector principle and person perception:  

• Judging presence of anger modified by:  

• Target attributes indicative of threat (ex sex and eye gaze) 

• Perceiver attributes increasing vulnerability (ex sex) 

• Research in which have a man hold a knife vs a spatula  

• Functional projection: projecting an emotion onto a person  

  • People felt the guy holding the knife was a lot angrier than holding the spatula  

babies and plants touching time experiments

• Also included categories of fear and disgust (used as controls) no significant difference here 

• Other self-protection adaptations: plant caution in infants  

• Categorized objects into thorns and no thorns  

• Have plants, a novel object (all of the features of a plant but not actually a plant) and then tools (hair brush vs shovel) 

• Measured touching durations  

• Spending less time touching something = caution  

• Infants spend less time touching the thorny objects vs the non thorny objects for new object and familiar object  

• Infants overall show less time touching the plants and no difference in time between thorny vs non thorny plants this shows a historic distrust of plants (expected) 

• Summary of adaptations for protecting oneself from environmental dangers  

• Fear= adaptive emotion in response to danger  

  • Characterized by smoke detector principle and the adaptive conservation hypothesis 

2 strategies to combat disease

• Strategies to combat disease 

• Physiological immune system, but: 

• Metabolically costly  

• Generates collateral tissue damage  

• Requires tailored defenses  

• Behavioral immune system (BIS) 

• 1^st line of defense against disease  

  • Reduces metabolic costs associated with immune system activation 

•  Why do we experience disgust?  

• Disgust  

• Specific facial expression (cross-cultural universal) 

• Distinct physiological response: nausea  

• Characteristic actions: avoidance and withdrawal 

• Is disgust an adaptation to disease? 

• Showed pictures of things that were not disease relevant vs disease relevant  

• Huge effect size difference between the 2 images  

• Images with disease cues evaluated as more disgusting  

• Found across cultures  

• Could argue it is observational learning but no avoidance of contaminants is found in hunter-gather societies (no knowledge of germ theory) and found in nonhuman animals (the apples and the monkeys and the apples with the feces) 

• Disgust prompts avoidance of infection  

• Cues to infection/contamination -> disgust -> avoidance  

• Disgust can promote prophylactic behavior: 

• Hand-washing  

  • Condom usage 

• How is disgust functionally flexible?  

• Evolved psychological mechanisms are characterized by functional flexibility  

• When costs of avoiding disease too high or benefit too low then we should expect that disgust is low 

• BIS characterized by functional flexibility  

• Strength of disease avoidance mechanisms are context dependent  

• Disgust varies by age and sex  

• Older people experience less disgust  

• Bc strength of selection pressure acts less strongly after you have reproduced 

• Males experience less disgust than females  

• Risk avoidance difference by some  

• Bus females have higher disgust sensitivity bc they looked over kids so it needs to be higher to help facilitate this and protect their weaker immune system 

• Disgust sensitivity increased when immune system is suppressed  

  • When benefits of behavioral avoidance are high  

times when immune system supressed so increased disgust

• Pregnancy  

• Recent illness / vulnerability to infection 

  • Immune suppression from aspirin (vs placebo) 

• Disgust decreased in service of meeting other goals  

• Energy need  

• Sexual arousal  

  • Parenting  

• What’s the relationship between disgust & the biological/physiological immune system? 

• Disgust prompts avoidance of infection  

• Cues to infection/contamination -> disgust -> avoidance  

• Disgust can promote prophylactic behavior: 

• Hand-washing  

  • Condom usage 

• What’s the parasite stress model of sociality? What research supports this idea? 

• Parasite stress model of sociality: infectious diseases* shape human psych and social behavior (both proximate and ultimate)  

• Historical levels of threat exert a stronger influence vs current threat  

• Non-zoonotic (human to human) disease rates exert a stronger role vs zoonotic (diseases that are in non human animals ) 

• Areas with higher historical pathogen load and higher non zoonotic infectious diseases are correlated with differences in personality, individualism differences and sociosexuality  

• Decreased extraversion, openness to experience, sociosexuality (SOI) (measures someone's willingness to engage in casual sex) 

• Decreased individualism and increased collectivism  

• Experimentally: 

  • In presence of a disease threat people had a lower sociosexuality (SOI) score not the case in other situations 

•  What’s the relationship between pathogens, sociality, & politics? 

• Social conservatism: sociocultural value system encouraging strict adherence to social norms / traditions (promotes ingroup cohesions) (set of beliefs that attempts to measure/ control the norms/ behaviors of others)  

• Positive relationship between BIS and social conservatism measures  

• People who score high on social conservatism are more likely to score high on disgust sensitivity and BIS  

• Pathogen avoidance -> sociosexual orientation/ sexual strategies -> social conservatism  

• High levels of pathogen avoidance -> low SOI -> higher levels of social conservatism  

• Consistant with the idea that people who are prudes functions to try and get people in their environment to follow them and their ideals  

  • Higher social conservatism is related to higher strength in males 

• BIS carries implications for prejudice and xenophobia  

  (type of prejudice, immigrant thing with pathogens vs war thorn, smoke detector principle)

• EP seeks to understand why these issues exist doesn't equal justification or excuse (naturalistic fallacy) 

• Traditional approach to intergroup (between 2 groups) prejudice: general negative feeling/evaluation towards outgroups  

• EP approach to intergroup prejudice: feelings towards outgroups vary based on specific threat group is perceived to posed  

• Describes an immigrant and said how likely people would be to let them into the US  

• From pathogen rich country: 45% for males and 55% for females in said to be allowed in -> no sex difference, low existance  

• From Violent war torn country: men 55% women 85%  

• More ok with women than men bc females pose less of a percieved threat  

• Disgust and the smoke detector principle:  

• Bias toward least costly error -> high prevalence of false alarms  

  • Least costly error here is a false positive (think they are sick but arent) 

How the BIS Fosters Prejudice and contributes to prejudice against people who have ____

• Cues of diseases vary widely -> system rigged to pick up on any deviation from the norm  

• Disease over-perception bias: assuming others with anomalous features pose threat of infection when they do not  

• Contributes to prejudice and stigmatization against:  

• People with disabilities  

• People with facial birthmarks 

• People who are obese 

• Immigrants  

• Over perception of diseases cues fosters xenophobia and out group prejudice  

  • Disease threat/concerns -> anything unfamiliar = potential contaminant 

pregnant women and xenophobia

• Pregnant women are more likely to be xenophobic especially during the first trimester of pregnancy when immune system is suppressed  

  • By-product of mechanisms treating anything unfamiliar as a potential infection cue  

people who think about this as an adaptation

• Less bias against familiar outgroups  

  • People think that this xenophobia is an adaptation bc they think that the infections of outgroups are more infectious/ dangerous -> this thought is a by product of our system that detects anything as a threat 

strangers and disease avoidance correlations

• Correlations between disease avoidance traits and positive immigrant attitudes 

• Negative correlation (more neg attitude) with eastern african immigrants  

• Positive correlation (more pos attitude) with eastern asian and eastern europe 

• Less bias about more familiar stereotypes  

• Model minority sterotype  

• Strangers: comfort w/ contact percieved health and similarity to locals  

• The more similar the more percieved health  

• More similar to us viewed as less of a disease threat even if they have a disease cue  

  • Strangers look sicker

hijacking the bis to lead to prejudice

• BIS can be hijacked to promote human rights violations  

• Nazis (Jews compared to rats), Rwandan Genocide (Tutsis compared to cockroaches) 

• Hijacking the BIS: messaging matters  

• When unhygenic vs control framing used roma (gypses) viewed as  

• Having decreased human emotions  

• Increased disgusting -> support for deportation  

• Did media framing of covid-19 increase prejudice towards Asians? 

• Emphasizing connection between china and covid but not a general health threat  

  • Increased anti-asian prejudice and overall xenophobia  

• Summary of digust and bis  

• Disgust and bis motivate avoidance of illness and infection  

• Characterized by functional flexibility  

  • Not uniformly positive or negative 

Why do we like sweet taste?  and not like things that taste bitter

• Tastes helps identify safe and nutritious foods  

• Most naturally occurring substances that taste bitter contain toxins at some concentrations  

• Sweet=safe (&calorically dense) 

• Nothing in nature that is sweet tasting that is poisonous  

  • Adaptive significance: aversion to bitter tastes may have been selected for to help prevent ingestion of toxins  

Lamarckism:

change through inheritance of acquired characteristics 

• Mistaken view wrong  

  • The giraffe example with the neck getting long  

Strength of selection pressure determines

how quickly a phenotype spreads  

• Ex predator avoidance in mosquito 1 bird only eats mosquito and 1 eats a diverse diet  

  • The one that only eats the mosquitos is a stronger selection pressure on the mosquito  

2 meanings of adaptations: (not an alternative hypothesis) 

• Adaptation: reliably developing characteristic produced by natural selection that solves fitness-relevant problems  

• Phylogeny (origins): original function (ex feathers for insulation) 

  • What was the original function when it first emerged 

• Functional consequence: recent/current adaptive function (peacock tail and mate attraction) 

  • What is the more recent function of the trait  

  • These are 2 categories of ultimate explanation  

All species have a nature

(characteristics that define the species) 

• "human nature" psychological traits (generated from decision rules, emotions, learning mechanisms, etc) favored by selection  

• Also known as evolved psychological mechanisms  

  • Domain specific view of the mind

Common dislikes promote adaptive food selection 

• Dislike of veggies (especially by kids)  

  • Adaptive benefit: reduces exposure to plant toxins  

  • Many plants (esp. Bitter-tasting ones) contain small amounts of toxins (allyl isothiocyanate)  

  • Modified by social influence and age  

    • For parents you eat the veggie and show them its safe and repeated exposure  

Aversion to food showing signs of contamination  

• Adaptive benefit: minimize ingestion of harmful bacteria 

• People even don't want to eat misshapen foods  

• Bonobo's and apples 

  • 90% of bonobo's eat the normal apple but if the apple has dirt or feces on them a lot less of them are willing to eat the apple 

Food neophobia:

caution with new food  

• Adaptive benefit: avoiding potential harm  

• Modified by social influence and context and repeated exposure 

• Want to test in rats if different spices in rats food will lead to avoidance: they did this by putting spices on it and then measured how long it took them to approach the new food  

  • Rats most hesitant on day 1 of new food 

  • If expose them to it across repeated days values go down= they are getting used to the food  

  • In children after repeated exposure to disliked veggie the more they are exposed to it the more they are willing to eat it  

Food preferences are functionally flexible  

• Preferences shift in cases when it is flexible for them to shift  

  • See moldy orange (some nutrients some pathogens)-> computations (influenced by situation, resource availability, personal vulnerabilities and pregnancy): identify edible food    -> output/outcome  

• When deprived of food:  

• Increased visual attention to food  

• Increased approach ( and decreased facial disgust) towards disgusting food  

• When deprived of food more willing to engage bc you are starving  

• With individual taste preference: when someone is deprived of food their own individual taste preference is less important  

• But portion size and waiting time are more important  

• Why people don't know what to eat when they are hungry bc own individual taste preference goes down  

Garcia Effect: Conditioned Taste Aversion: (defies laws of classical conditioning)  

• Discovered this in rats  

• Have rats drink sweetened water (CS) 

• Then expose the rats to radiation and they get nausea (US)  

• Then when rats reexposed they won't drink the sweet water (CR) 

  • Very specific to the aversions it incurs it is only through nausea that the rats won't eat the food again  

Selective social learning of plant edibility in infants  

• Plant's produce toxins to avoid being eaten (think bio 131) 

• Given high costs of trial and error learning infants should have mechanisms to allow them to determine what plants are edible  

• 18 month old infants try to see if they differential id plants as a food source: humans should be faster to id a plant as a source of food vs something that looks like a plant vs not  

• Infant sees person put fruit from plant in their mouth or behind their ear did same thing with the artifact 

• For the food behind the ear there is not a significant choice between plant vs artifact  

• When they look at the in the mouth action they chose the plant more when it is the plant option and in the mouth  

  • When infants shown plants vs other objects infants look more frequently to the adults for advice  

many plants contain small amts of toxins. why

a. byproduct of nutrients being absorbed into the plant

b. method of storing nutrients that may need

c. adaptation for chemical warfare against other plants

d adaptation for reducing the likelihood of getting eaten

d

the antimicrobial hypothesis covered in the buss textbook predicts that people will

a. spice foods more in cold climates

b spice foods more in hot climates

c be more averse to microboes in hot climates

d be more averse to microbes in cold climates

b

based on content presented in buss textbook hunting can account for the emergence of all of the following patterns of behavior except

a. male coalitions

b maternal investment

c sexual division of labor

d. social exchange

b

which of the following if found would not support wrangham’s cooking hypothesis

a. humans experience lower fitness on raw food diets

b. digesting raw foods burns more calories as they are harder to digest

c. cooking is universal among human societies

d. cooking decreases the net energy value of food

d