Evolutionary Psychology Exam Notes PDF

Extensive notes for envolutionary psychology exam geschreven door kworring www.stuvia.com Gedownload door: ypsalinasalgado | [email protected] Dit document is...

Extensive notes for envolutionary psychology exam geschreven door kworring www.stuvia.com Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Lectures Evolutionary psychology Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Index Lecture 1 – Foundations of evolutionary psychology............................................................................ 4 Introduction.................................................................................................................................... 4 What is evolution (via natural selection)?..................................................................................... 7 Sexual selection.............................................................................................................................. 8 Lecture 2 – Adaptations for survival.................................................................................................... 14 What is evolutionary psychology?............................................................................................... 14 What are psychological adaptations?.......................................................................................... 14 How to generate (and test) an evolutionary hypothesis?........................................................... 16 Adaptations for survival: Getting food........................................................................................ 17 Adaptations for survival: Fear and disgust emotions.................................................................. 18 Lecture 3 – Men’s and Women’s long term mating strategies........................................................... 20 Parental investment theory......................................................................................................... 20 Evidence for parental investment theory.................................................................................... 21 Adaptive problems in long-term mating (more so for women).................................................. 22 Adaptive problems in long-term mating (likely more so for men)............................................. 27 Darwinian puzzle of homosexuality............................................................................................. 29 Lecture 4 – Short-term sexual strategies............................................................................................. 31 Short-term mating........................................................................................................................ 31 Adaptative challenges for short-term mating for men............................................................... 33 Costs for short-term mating......................................................................................................... 34 Potential adaptive benefits of short-term mating strategy for women..................................... 35 Lecture 5 – Challenges of parenting and problems of kinship............................................................ 40 Differences in parental care......................................................................................................... 41 I. Estimating genetic relatedness of offspring............................................................................. 42 Tests of the paternity uncertainty hypothesis: Genetic Relatedness of Offspring.................... 43 II. Ability of offspring to convert parental care into fitness........................................................ 45 III. Discriminating investments between the children................................................................ 45 Theory of parent-offspring conflict.............................................................................................. 46 IV. Investing resources in alternatives for own children............................................................. 48 Lecture 6 – Problems of group living: Cooperation............................................................................. 49 Altruism......................................................................................................................................... 49 I. Altruism as byproduct or mistake............................................................................................. 51 II. Kin altruism............................................................................................................................... 51 III. Reciprocal altruism.................................................................................................................. 55 IV. Altruism via indirect reciprocity............................................................................................. 58 Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Lecture 7 – Problems of group living: Aggression, war and conflict between sexes............................ 60 Lecture 8 – Conflict between the sexes................................................................................................ 61 Lecture 9 – Status, dominance & leadership......................................................................................... 62 Lecture 10 – Towards an integrated, unified psychology..................................................................... 63 Lecture 11 – Practice exam, Q&A about exam, assignments................................................................ 64 Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Lecture 1 – Foundations of evolutionary psychology Introduction Picture of a skull and what it can say about the life back then. - The skull was found in Northern of Spain in a cave complex. - There were skeletons and skulls found of 28 individuals. - The skull is 430 thousands years old → Skull of a Neanderthal. - The skull is from an adult male. - Based on the teeth you can predict what kind of diet the individual use. - What was the social nature of these individuals? o There is a hole in the skull and dents → Looking and these injuries scientists predicted that the individual was beaten up by another individual that was righthanded with an instrument → First evidence of human violence. o You can also see some healing of the skull → Individual did not die immediately because of this attack but was probably cared for by others. Aim of the course → Try to study human behavior by taking a deeper historical perspective. Why do humans do the things that they do? - What are the qualities of romantic partners that we go for? Are there any sex differences? - Why do people engage in homosexual relationships? What is the evolutionary explanation? - Why do people break-up? Why do we loose attraction to one another? - Why are we attracted to stimuli of sexual nature? Is there a difference between sexes? - Why do we have good parenting skills? - Why do we like certain foods? - Why do we engage in arts? - What is the attraction to social media? - Why do we talk? Why are there so many languages? - Why do we have religions? - Why do we work? - Why do we engage in sports? - Why do we take risks? - How do we deal with pandemics and viruses in our environment? - Where does our morality come from? - Why do we follow leaders? - Why do we show violent behavior? Why? - Why do people do certain things? - Can we explain them with existing theories in psychology? - Could we gain insights by thinking about humans as a biological species, subject to the same environmental pressures as other animals? Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Evolutionary psychology: Short overview - Evolutionary psychology is the study of human behavior, affect and cognition from an evolutionary perspective. - Using evolutionary theory to understand why the human mind works this way and how it has been designed. o What are the functions of the mind and the brain? - In effect, it means viewing humans as part of the animal kingdom, subject to the same laws of evolution, natural selection, etc. o This might seem contentious! (but there is really no alternative to explain human behavior). Every species has its own nature. - The nature of a dog is different than the nature of a cat. o A dog will immediately eat all the food you give him, even when he is full. ▪ A dog is evolved from wolves that live in packs → There is always competition for food. ▪ The dog therefore thinks he needs to eat his food as quickly as possible because he is afraid that another dog will come and eat it even if you have only one dog. o A cat will only eat when he is hungry. ▪ A house cat has evolved from wild cats that are solitary hunters. ▪ Cats have a territory and do not allow other cats in their territory. ▪ The house of the cat is his territory so the cat knows that there won’t be another cat so they can leave their food without worrying that another cat will eat it. History of evolution - Greek philosophers (600-400 BC) → Humans were acting the way we do because some kind of air was floating through us that guide us. - Aristoteles (300 BC). - Medieval Christianity (16th century) → Humans are made by a god. o Hierarchy → Humans are on top of all the animals with higher intelligence. - Lamarck (18th century) → Humans and animals share certain things. - Darwin (19th century) → Evolution theory. - Mendel (19th century) → Came up with the mechanism of genes. - DNA discovery and the Modern Synthesis in Biology (20th century): o 1. function (evolution) and 2. mechanism (gene). Evolution pre-Darwin → Jean-Baptiste Lamarck (1744-1829). - 1. The inheritance of acquired characteristics. - 2. Use and disuse of traits (e.g., muscles). - Example: o The original short-necked ancestor of a giraffe keeps stretching its neck to reach leaves higher up on a tree during his development so he can reach the leaves when he is an adult. o This training of the neck and learning will be passed on to the next generation which eventually leads to Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen progressively longer neck because the next generation will be better in training the neck. - According to Lamarck → Anything that happens during your life will be passed on to the next generation. Charles Darwin - The voyage of the Beagle (1831-1836). - Book “On the Origin of Species” (1859). - Darwin’s finches on the Galapagos islands: o He found different species on the different Galapagos islands. o The different species also show some similarities → Maybe there was an original ancestor that they shared together but because the birds started to live on different islands the beaks started to change into a beak that was most favorable to the food that was available on the specific island → Natural selection and adaptation. Natural selection and survival of the “fittest” - Darwin quote: o “As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.” - In short: o Because there are too many individuals born, only the individuals that are most adapted to the environment will survive and have offspring, giving the best genes to the next generation and over time the best adapted modified form of a gene will overrule. Survival of the friendliest? - For humans it is important to survive and thrive in big groups which will result in selecting the genes that are most favorable to for social interactions, caring, empathic, etc. - So the friendliest individuals would have the most advantage and therefore natural selected for → This theory is a little bit of a stretch. The tree of life - Over time organisms adapt to their environment and occasionally a new species is formed. - DNA studies reveal that humans share a common ancestor with the bacteria, some 4 billion years ago. - 70% of our DNA is the same as an earth worm. - Organisms and species change but the building blocks are still the same. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen The primate tree - 99% of our DNA is similar to non human primates. - By looking at the DNA similarities between species and how often a DNA mutation occurs and result in a different species you can make a historical tree. - DNA resemblance is not everything → Also similarities in environment matters for similarities in behavior. A walk through human evolution - 6 million years ago we had a common ancestor with a chimpanzee but we are not descended from the chimpanzee → After the common ancestor the chimpanzee and the human started to evolve separately in different species. - Neanderthals and homo sapiens were living next to each other but the Neanderthals did not make it and went instinct and the homo sapiens are still living. o One theory → Neanderthals lived in the North of Europe hunting on mammoth. Homo sapiens came from Africa and went to the North of Europe competing with the Neanderthals for food. Homo sapiens were better organized and could relay more on each other when there was little food so that is why homo sapiens lived and Neanderthals did not. o Second theory → Homo sapiens killed the Neanderthals. o Third theory → Homo sapiens and Neanderthals got mixed together and eventually the Neanderthals were not an different species on its own anymore. ▪ 6% of our DNA is Neanderthals DNA. Resistance against evolutionary theory, still ongoing. - People didn’t want to believe that they may had an common ancestor with an monkey. Charles Darwin (1809-1882): Grandfather of evolutionary psychology. - “In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation”. What is evolution (via natural selection)? Poll-question 1. Cutting off the tail of a mouse has what effect on the next generation(s)? a. The mouse tail will become shorter. b. The mouse tail will become longer. c. The mouse tail stays equally long. Answer: - The right answer is C. - If you would think like Lamare → Things that happen in life will be given to the next generation so the next generation of mouse will also have a shorter tail. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen - But Darwin said → The DNA (what the mouse was born with) is not changed when you cut of his tail so the next generation will still have a normal tail. Three components of natural selection: - Variation → There is variation between individuals. - Inheritance → Some of the variations are genetically driven so they will be passed on from generation to generation. - Selection → Having a certain trait will give you a specific advantage which can lead to more offspring that will have the certain trait that gives the organism an advantage. The giraffe neck → How does natural selection work. - There is individual variation in traits → Some giraffes have a longer neck then others because of a spontaneous mutation. - Some trait variants allow their bearers to better compete for resources → Giraffes with a longer neck can reach more leaves an thus have more food and could therefore reproduce more. - If these traits are inheritable then they are passed on from generation to generation - The result over time → Individuals of a species become better adapted to their environments. A mechanism for evolution via natural selection → The gene. - Darwin did not know that the beneficial traits were past on by genes. - Gregor Mendel discovered the mechanism of genes. o An example of how genes work → Mendel’s peas. ▪ Crossing a white plant with a red plant will lead to ¾ of the next generation that will be red and ¼ of the next generation that will be white → Red gene is dominant over white gene. The modern synthesis in biology and DNA discovery (1953). - Mixing parental genes (Mendelian genetics). - Recombination. - Mutation → New genes emerge. Lamarck’s recent come-back? EPI genetics. - During your lifetime the expression of your genes can be changed but not your DNA itself. - Example: o A women who is pregnant in the Dutch hunger-winter gets a child that will still suffer the consequences of the hunger-winter even though they are born after the hunger- winter → They die at a much younger age. Sexual selection Sexual selection - Traits that are selected because they make you more attracted to the opposite sex. - Darwin: “The sight of a feather in a peacock’s tail, whenever I gaze at it makes me sick!” o Darwin could not understand why the peacock had such long feathers because it did not give the peacock an advantage to survive. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen o Darwin’s idea → The feathers of the peacock evolves because it gives him higher chances to mate. Two forms of sexual selection - Inter sexual competition → Traits that are passed on because they are good at attracting opposite sex mates. o For example → Pretty feathers of birds. - Intra sexual competition → Traits that are passed on because they are good at winning same sex competitions for mates. o For example → Big antlers of male deer to fight with. o For example → Gossiping between females to exclude rivals. Poll question 2. Which human trait is the most likely a product of sexual selection? a. Intelligence. b. Psychical attractiveness. c. Food preference. Answer - The right answer is B. - Intelligence could also be a product of sexual selection but is not most likely. o Intelligence evolved because of natural selection because it allowed us to better survive. o But intelligence could also be something that makes you attractive to the opposite sex. Runaway effects in sexual selection. - Some man are strong → Variation. - Strong men provide more care for their children. - Women prefer strong men because they provide more care for their children. - A given woman really likes strong men and will have sex with a strong men: o Sons are stronger. ▪ Stronger sons leads to reproductive success → Strong sons attracts more/better woman. ▪ Daughters of strong son also really like strong men → More woman that prefer strong men. ▪ Sons of strong son are also strong. o Daughters also really like strong men → Daughter’s son is also a bit stronger. - If this continues than men will become stronger and stronger over time. - So what happened? o You started with an initial variation in strongness and because of the preference of the woman, one variation is selected (more strong) and eventually this trait will become dominant in the population and men are evolving being stronger. - There are also limits → A men cannot become endlessly stronger. o Strength also means more calorie intake for example. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Humans are the products of evolution. - Muscles, veins, organs, bones → Different organs and incredibly complex. - Not perfect, but functionally adapted to certain environment! - What environment? → The Savannah. The Savannah hypothesis - Humans evolved on the Savannah. o Our ancestors lived in the woods. - Walking upright was an advantage at the Savannah. o You could see better (predators, searching for food). o You could walk longer distances. The most complex organ of all → The human brain. - Triune Brain (Maclean, 1960). - Brain can be divided into 3 parts: o Reptilian brain and brain stem (avoid and approach) → Oldest part of the brain. ▪ Regulates responses to heat and cold. ▪ Regulates breathing and other vital functions. o Paleo-mammalian complex → Middle part of the brain. ▪ Limbic system → Controlling emotions like fear, anger, etc. o Neo-mammalian complex → Newest part of the brain. ▪ Neo cortex that is important for planning. ▪ Mostly developed in humans → Higher intelligence functions. - The brain is also a product of natural selection. Increase in brain size - Overtime the brain size has grown a lot → Our brain is now 1,5 kg. - Our brain consumes 20% of calorie-intake → Brain is very important. What factors drove the increase in the hominid brain size? - Ecological factors (e.g., climate) → We need a big neocortex to deal with climate fluctuations. o When there is drought you need to be able to change food resources and find new ways of getting food. o You need different strategies when it is could and when it is hot. - Technology → As we started to use more advanced tools, bigger brains developed because only the individuals with bigger brains could use the more advanced tools. o Unlikely theory. - Social factors → A bigger brain could maybe help to live better in a large group. - Cultural factors → Individuals with bigger brain could learn better from each other. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Out of Africa migrations: Modern humans approximately 60K years ago. - Modern humans haven’t been around for a very long time → Only 60 thousand years ago. o Hominids have been around on earth for about 1,5 million years ago. - The modern humans radiated from east of Africa to the rest of the world. o In Southern Europe we met the Neanderthals. Evolution is not a theory but a fact! - The earth is really, really old → ~4,5 billion years. o This is confirmed with a lot of research. - DNA evidence shows that all living organisms are of common descent → The building blocks (DNA) of all organisms are the same. - Evidence is found for intermediate life forms → For example, feathered dinosaurs that are the intermediate between dinosaurs and birds. o All birds originate from the dinosaurs. - Evidence for natural selection in action. o For example, moths → There were two kinds of moths, the peppered moth (white and grey) and the black moth. ▪ First a lot of peppered moths were seen and not so many black moths. ▪ During studying of this moths, the industrial revolution took place and a lot of pollution affected the color of the trees → The trees got darker and this lead to the disappearance of the peppered moth and the appearance of the black moth → The black moth was much more camouflaged than the peppered moth and therefore the chance to be eaten was less and thus survival was better. ▪ When the pollution got less and the trees became lighter again, the peppered moth reappeared again. History of evolutionary psychology - Sigmund Freud → “Sex is important!” o He was a Darwinist → Believed in natural selection. o Freud thought that sexual instincts were very important. - William James → “We have lots of instincts!” o He was also a Darwinist. o Our behavior is driven by a lot of different instincts for everything we do. - Skinner’s Behaviorism → “Anything can be learned as long as it is rewarded!” o Did a lot of research on animals. o He thought that at the start of our life our brain was empty (blank slate) and during our life our brain becomes programmed by rewarding good behavior and punishing bad behavior. o He also acknowledged that not everything can be learned and there was some build- in machinery. - End of behaviorism? → Harlow and Garcia-experiments. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Famous Harlow studies - Baby resus monkey was taken away from his mom. - Then the baby resus could choose between two fake mothers. o One was made out of a cloth that could keep the monkey warm. o The other one was a food dispenser. - If behaviorism was right → The monkey would choose the food dispenser because then the monkey gets rewarded with food. - Instead the monkey sometimes took some food from the food dispenser but spend most of his time with the cloth because the monkey probably has some build-in preference for bonding with a mother that is warm and nurturing and could therefore not be trained by rewarding him with food. - Conclusion → We come with a programmed brain in the world → Evolutionary psychology is based on this. E. O. Wilson (1975) - Sociobiology → There are all kind of social structures in animals, so what about humans? → They also have some social structures that may have some genetic component. - This was quite controversial. Richard Dawkins (1976) - Selfish gene (1976): “It is the gene stupid” - Humans are nothing more than survival machines for genes → Our genes want to have as many copies of them in the next generation as possible so the genes build bodies that will carry the genes and pass them on to the next generation. - Selfish gene does not mean that the gene makes humans selfish. Cosmides and Tooby (1992) - Most associated with the field evolutionary psychology. - The adapted mind → The brain is a swiss army knife. o The mind has different tools and each tool has a specific task they are good at. Misunderstands about evolutionary psychology: - Human behavior is genetically determined → No, the environments and learning matter too. o If behavior was genetically determined we would not have free will or control over ourself. o Example → We have an innate capacity to speak but which language you will speak is determined by the environment you grow up in. - If it is evolutionary, we cannot change it → No, we can shape our own future. o Example → It would be evolutionary better to have more wives as a successful man but we have the possibility to decide if we really want that or not. o We are not a slave of our instincts. - Adaptations are optimally designed → Not always in new environments. o Example → Our body is not good designed to work long days behind a computer like we do now and this is why we have a lot of body problems like backpain. - It’s an adaptation so it must be good → No, what is, is not what ought (naturalistic fallacy). o An adaptation could be good for one person but not good for another person. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Levels of analyses Biologically innate Culturally acquired Language capacity English, Dutch, sign language Desire to eat food Taste for pizza, sushi, kroket Desire for social status Money, strength, publications Desire to be attractive Slim, voluptuous, tie, penis sheath Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Lecture 2 – Adaptations for survival What is evolutionary psychology? Evolutionary psychology - Evolutionary psychology focusses on the function and adaptiveness of human behavior. - It rest on the principle that your mind and behavior is shaped by the process of evolution. - Questions that evolutionary psychologists ask: o Is this behavior functional? o Is this behavior adaptive? - Mis match theory → Some of the things we do might be adaptations to a different environment than we currently live in. o Things that might be useful in the past, are not so good now. - Some adaptations are still useful: o Morning sickness → Protect the baby against harmful stuff because foods that are most likely to evoke disgust are the foods that are most likely to harm the baby. - How do you test a evolutionary theory? o Looking for clues → Does the trait or mechanism exists as a consequence of evolutionary processes? ▪ Variations map onto environmental differences. ▪ Evident at population level? ▪ Fitness consequences? ▪ Evident across cultures? ▪ Evident across species? ▪ Fulfills a specific function? o The best evidence is when the trait or mechanism is seen across cultures or accros different species. - Evolutionary psychology is not an explanation of everything. - Evolutionary psychology is not a prescription for behavior → Just because it seems to come naturally does not mean that it is right. - Evolutionary psychology is not justification for discrimination. - Evolutionary psychology is not tied into one time period. - Evolutionary psychology is adaptive. What are psychological adaptations? Adaptation → A solution to a problem. Evolution has three products: - Adaptations → Inherited characteristics that are naturally selected because they helped to solve a problem of survival or reproduction → The trait was beneficial for survival and/or reproduction. o Still functional → Parenting is still important to increase the survival of offspring. o Mismatched → Used to be adaptive but not anymore. ▪ For example → Preference for sweet and fatty foods. When there is not a lot of food around, it is very good to like sweet and fatty foods because these foods give a lot of energy. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Now there is a lot of food so there are no barriers anymore but we still have the same preference for sweet and fatty foods which leads to stuffing us with a lot of sweets which now could lead to obesity, cardiovascular diseases. - By-products → Carried along with adaptions but without function. o Belly button comes is very different shape and sizes but it has no function. - Noise → Random effects, no function. o Eye color, musical taste. Adaptive problems and solutions (adaptations). Problem Adaptation Result Handling objects for survival Flexible thumb Ability to grasp objects Spotting game (animals you Two legs (standing up straight) Seeing farther and run longer can eat or predators) Get ripe fruit from trees Color vision Detect which fruit is edible, which fruit is ripe Kids need to survive Parental care for kids Enhances survival of kids You are vulnerable on your Group living Together you can do much own more Find a good mate Like attractive mate Better genetic quality offspring Snakes kill Fear of snakes Get bitten less Group may abandon you Conform to group Avoid social exclusion Psychological adaptations are evolved psychological mechanisms or if-then decision rules. - Psychological adaptation solves a problem related to survival or reproduction. - Evolved psychological mechanism → Mental algorithm → In our brain there are decision rules programmed that tell us what to do in certain situations: o Individual takes in specific inputs → I see a snake. o Then the individual thinks about the decision rule → If I see a snake I need to become fearful because a snake is dangerous. o Individual transforms it into adaptive outputs → Individual starts to sweat, eyes focusing, run away. ▪ Outputs can be physiological, psychological, behavioral or combinations. - Individuals that do not have this if-then decision rule would have been bitten by the snake and killed and thus could not give his/her genes to next generation → So over time this decision rule evolved and became part of our nature. Evolutionary psychology: Infant crying. - Distinguish the proximate from the ultimate causes of this behavior. o From what happened milliseconds ago to what happened millions of years ago. o Proximate explanations: ▪ Baby is cold. ▪ Baby is hungry. ▪ Mum leaves room. o Ultimate (functional) explanations: ▪ Crying elicits care and defensiveness from mothers and other caregivers, which will increase the likelihood of survival of the baby and hence lead to fitness benefits. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen How to generate (and test) an evolutionary hypothesis? Two strategies: - Bottom up → Observation and then explain from theory → Inductive approach. o This is what Darwin did. o How can Donald Trump get that many top models as partner? ▪ This could maybe be because women prefer wealthy men. - Top down → Hypothesis from theory → Deductive approach. o You have a theory and then look for an implication of this theory. o Parental investment theory → Women prefer wealthy powerful men because they will provide better for their children (resources, protection). ▪ This is why Donald Trump get that many top models as partner. ▪ Woman should be more picky in who they will mate with in order to have a good future for her offspring. Testing an evolutionary psychology hypothesis. - Sexual selection hypothesis → Men show off their physical strength more in the presence of women. o Why? → Because showing off physical strength they are more likely to be picked as potential romantic partner. - How would you test this? o Field study → Observe male behavior in bar or gym when there are more women present. ▪ Also attractiveness of the women plays a role. o Lab study → Present female faces on screen (vs. male faces) and have men do a competitive task with each other. o Cultural study → See if physically stronger men have a younger/more attractive wife in various cultures. Men behaving nicely - Are men more likely to be more nicely (helping a old lady) when they know that they are being watched by a women that is a potential mate? - Are men more likely to donate money to charity when they know they are being watched by a potential mate? o Results → Men tend to give more money when a female was sitting next to them compared to when a man or no one was sitting next to them. ▪ This was not seen in the female group. Research methods evolutionary psychology → It is important to collect data from many different fields before make a conclusion. - Psychological experiments. - Cross cultural, anthropological studies. - Physiological and brain imaging methods. - Genetic studies. - Comparative methods (comparing different species). Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Comparative experiment → Monkey reject unfair pay. - Maybe in our genetic relatives we also have some behavioral similarities. - Experiment: o One monkey gets cucumber (not so delicious) when he gives a stone to the experimenter and the other one gets a grape (very delicious). o The monkey that gets the cucumber gets upset and does not accept this unfair pay → The monkey already has a sense of fairness just like humans. Adaptations for survival: Getting food Solution → Hunting - Meat → High caloric value (30% of diet). - Change from forest to grass lands with larger animals. - Provisioning for and beyond family. - Selected for new adaptations: o Tool use → Using spears, bow and arrow. ▪ The ability to throw. o Language → Allows us to coordinate. ▪ But with hunting you need to be quiet → So it is not logical that language came because we started hunting. ▪ However sign language probably did developed because we started hunting and this is origin of the first language → Gesturing and language are done by the same brain area. o New cultural practices: ▪ Controlling fire and cooking → By cooking our food it was much more easy digest it so our gut became smaller. Less energy was needed for our intestine so more blood could go to our brain which resulted into bigger brains. ▪ Sex based division of labor → Men hunt, women gather. This is not completely true. o Hunting on big game in small groups → Mostly done by men. o Hunting on small animals → This could also be done by woman. ▪ Spicing foods → Anti microbial hypothesis → Spicing your food kills the microbes. In warm climates the chances that microbes infect your food is high → In warm climates the most spiciest food is eaten (e.g. Thailand). Showing off hypothesis of hunting - Status competition between mostly men → Better hunters have: o More status. o More mates. o Can take better care of their children due to more resources (more surviving off- spring). - Support for this in many hunter gatherer societies. o Paraguay, Eats Africa, Botswana Namibia, Indonesia, Australia (turtle hunting) Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen The gathering hypothesis - Focus on women’s role in food gathering. - Gathering (plants, seeds, nuts) created new selection pressures. - Stone tools used for digging. - Multitasking → Gathering and taking care of young children. o Hypothesis → Woman are now better at multitasking than men. - Large portion of diet can consist of plants, but depends on region. o Plants collected by women can provide up to 70% of total calories. o Sexual division of labor at basis of sex typical adaptations? Male versus female adaptations to food collection → Hunting versus gathering. - Women → On average better with object memory location. o Women had to remember where they could gather nuts and seeds. - Men → On average better in spatial orientation. o Men had to hunt and had to find their way back to the camp after hunting. - Evolutionary hypothesis: o Maybe because males have tended to do the hunting in ancestral times which involves tracking and following then finding way home they are better at spatial tasks. o Maybe females are better in object location because of gathering past which involves remembering where something edible can be found. Color vision - What would be the evolutionary advantage? o Food hypothesis → Better spotting ripe, yellow fruit or edible red leaves embedded in green foliage (more men than women color blind!). o Social hypothesis → Better spotting changes in skin color due to emotional states and social sexual signals. ▪ Females may have honed these adaptations for their roles as care givers and ‘empathizers’ → For females it was more important or functional to pick up emotions like anger, shame as their role as care givers. Cultural similarities in sex-differentiated color preferences replication problem? - Testing Chinese and UK color preferences by having participants select between two images. o Women have a preference for orange/red/pink. o Men have a preference for green. - Replication failure? → A recent study failed to replicate this result. Adaptations for survival: Fear and disgust emotions Adaptive function of our deepest fears. - We created fears because of certain problems and thus made us more adaptive. - Fear of snakes → Because of poisonous bite. - Fear of spiders → Because of poisonous bite. - Fear of heights → Because of damage from fall. - Panic → The feeling that there is the possibility you are being attacked → Imminent attack. - Agoraphobia (fear of big groups) → Because in crowded places there is no escape. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen - Fear of disease → Because of contamination. - Separation anxiety → Because of loss of protection. - Stranger anxiety → Because of harm from unfamiliar. Fears and adaptive outputs - Flight → Better run than die. - Fight → Better fight than die. - Freeze → Avoid detection (not handy in traffic). - Faint → Submitting when no escape. - From fears to phobias → When evolved fear mechanisms are not calibrated well enough. o This could also be an mis match adaptation → The fear is activated in situations where there is no real danger. Disgust as adaptation - Disgust is easily detected. - Disgust is cross culturally visible → Maybe it is part of our nature. - Possible functions: o Disease avoidance. ▪ Poisoning. ▪ STDs. o Avoidance of non-cooperative individuals → Avoidance of individuals that are bad for your welfare. ▪ Moral disgust. More disgusted with strangers - 40.000 respondents on BBC website. - With whom they would least like to share a toothbrush? o 59.3% Postmen. o 24.7% Boss at work. o 8.9% The weatherman. o 3.3% Sibling. o 1.9% Best friend. o 1.8% Spouse/partner. Tackling meat consumption by invoking disgust. - Make people eat less meat by showing disgusting photos of meat. Pregnancy sickness as adaptation → Embryo protection hypothesis. - Hypothesis → Morning sickness helps to avoid toxins. - Evidence: o Vomiting expulses possible toxins. o The morning sickness is food specific → Red meat, alcohol → Only the harmful foods evoke morning sickness. o Especially in first trimester → This is when the fetus is most vulnerable. o 3.8% of women with morning sickness have a spontaneous abortion vs. 10.4% of women with no morning sickness. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Lecture 3 – Men’s and Women’s long term mating strategies Differences in short term and long term mating strategies: - Differences in goals: o For short term mating strategies → Getting casual sex. o For long term mating strategies → Resulting in marriage. - Men and women have different strategies. Mating video’s where a woman asks men to have sex with her and a man asks women to have sex with him. - To the female → 70 men said yes to the female and 30 said no. - To the man → 100 females said no to the men - Why is there a difference between men and women? - Do we also see this difference in different species? Parental investment theory Sex and investment per offspring. - There is a basic asymmetry in costs for men and women to engage in casual sex → Because we have different reproductive cycles. - Males: o Sperm infinite and inexpensive → Men renew their sperm constantly until they die. o Minimal investment in all respects → No pregnancy, no lactation. - Females: o Eggs limited and expensive (more energy needed). o Fertilization and gestation occur internally (in the uterus). o Energy consuming → 9 months pregnancy in humans. o Lactation → Several years in humans. o Once impregnated, cannot become pregnant for at least another 9 months. - So females engage less in casual sex because they have more costs than men. o Unwanted pregnancy. o Chance of getting raped. o Not getting enough investment because partner is not reliable. o And a lot more… Parental investment theory - The sex that invests more in offspring (typically, but not always, the female) will be more discriminating or selective about mating → They have a much higher bar who they have sex with because of the investments they would have to make. - The sex that invests less in offspring will be more competitive for sexual access to the high parental investing sex → This sex will be less choosy who they mate with and will compete with others. - Hypothesis: o In humans, women are the more investing sex. Hence, on average women are somewhat more selective about potential mates than men. o Evolution would have favored psychological adaptations, especially in women, that make them more selective in mate choice. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen ▪ Women want healthy looking men. ▪ Women want men with financial status. ▪ Women want men who is faithful. ▪ Women want masculine men. ▪ Etc. - In seahorses: o Here the males will fertilize and breed on the eggs → More investment. o Here the male is more selective about who they mate with. - Women are more focusing on long term mating than men because they invest more in it. - Why do we have to invest so much in our offspring?: o Babies come to the world very immaturely because a mature baby could not pass our birth canal because we are walking upright. Recap → Psychological adaptations are evolved psychological mechanisms or if-then decision rules. - Solves a problem related to survival or reproduction. - Takes in specific inputs. - Transforms it into adaptive outputs. - Outputs can be physiological, psychological, behavioral or combinations. For parental investment theory: - Because women invest more, they got the psychological adaptation to become more choosier and look for cues in men that will state that it is a good mating partner. - The women developed certain mating preferences. o These are different for men. o Mate preferences are shaped over thousands of generations. Evidence for parental investment theory Cross-cultural studies - Mate preferences that women have, should be seen in all women across all cultures in order to call it an adaptation. Poll question 1. Across cultures, male preferences for physical attractiveness __________ female preferences for physical attractiveness. a. Are valued more than b. Are equal to c. Are half when compared to d. Are valued less than Answer - The right answer is A. Poll question 2. Which of the following characteristics are rated by women as more desirable in a long term mate than in a short term mate? a. Kindness b. Religiousness Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen c. Youthfulness d. Patience Answer - The right answer is A. Cross culture study → Ranking the importance of certain traits in potential mate for long-term. - Women: o Women find mutual attraction and love the most important trait in men. o Then comes dependable character. o Then comes emotional stability, maturity. o Then comes the trait desire for home and children. o Good financial prospects is rank number 10 → Higher ranked than men. o Good looks is rank number 12. - Men: o The first 3 point are the same as women: ▪ Most important → Mutual attraction and love. ▪ Then → Dependable character. ▪ Then → Emotional stability, maturity. o On place 4 comes education and intelligence. o Good looks is rank number 8 → Much higher in de ranks than for women → Attractiveness is more important for men. o Good financial prospects is rank number 12 → Less important for men than for women. - Conclusion: o Men and women share a lot of traits they find attractive in a potential mate, but there are also some differences and this could be evidence for the parental investment theory. Adaptive problems in long-term mating (more so for women) Problem 1 → Selecting a mate who is able to invest in offspring. - Solutions? → Finding a mate with… o Good financial prospects (income). o Social status. o Older age. ▪ Women tend to prefer somewhat older men and men tend to prefer somewhat younger woman. o Intelligence/Ambition/industriousness. Evidence for good financial prospects: - Women find good financial prospects in marriage partner very important in different countries: o In Japan, Zambia, and USA more then 2 on a scale from 0 to 3 importance. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen o In Croatia and Australia around 1.5 on a scale from 0 to 3 importance. - Men find it less important. Parental investment-theory explains: Income and attractiveness as mate qualities. - For both men and women earning capacity becomes more important when the relationship becomes more serious → For female far more important then the for the male. - Physical attraction is already important when you first start dating and will continue to be important when the relationship becomes more serious → Men find it more important than the women. Sexy selfies (of women) linked to economic inequality in countries. - Sexy selfies were send more to men in a society where there was more economic inequality → Women do so to advertise herself to men with good financial prospects. Does higher-status leads to more children? - Yes, people with a higher-status have more children → More so for high-status men then for high-status women. - Maybe high-status for men is something to strive for because it enhances their chances for mating partners and getting more offspring. Age differences across cultures - Men tend to find women that are younger more attractive. - Women tend to find men that are older more attractive. - Why this asymmetry? o Women need men that are able to invest in the relationship when it comes to finances for example and older men tent to be more successful and have better financial prospects. o For men it is important that the women is able to conceive → Younger women are more fertile. Problem 2 → Selecting a mate who is willing to invest in offspring. - Solutions: o Dependability and stability. o Commitment cues (for example love). o Kindness. o Positive interactions with children. - Both men and women equally value these traits in a potential mate. - Women are looking more activity for these cues in potential mate then men. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Love as evolved commitment device. - Love is a psychological adaptation to signal relationship commitment → This is important because both parents are needed to care for offspring for a very long time and love is a mechanism to cooperate with each other. o Evolutionary pressure? ▪ Hunters were away for weeks and the women stayed behind. ▪ How would the hunter know that the woman would stay faithful when he was away? → Managing this by expressing love and showing commitment to the relationship so the female would not cheat on him. - Acts of commitment: o Talk about marriage. o Expressing a desire to have children. o Fidelity → What kind of reputation has the potential mate? o Channeling resources exclusively to relationship. ▪ Spending time. ▪ Spending money. ▪ Wedding ring → A ring is really exclusive to the relationship and thus a investment to this particular relationship. Men’s counter-strategies - In general, women will seek men who display characteristics of commitment and resources as a potential mate. o Personality, education, wealth, age, family background etc. - We expect men to have developed counter strategies to deceive women about their resources/commitment: o Pretending to have a greater status (or potential status). o Feigning greater commitment than truly willing to provide → Talking about marriage when he actually doesn’t want it. - Females use gossiping against these counter strategies. o By gossiping they can detect deception of the males. Problem 3 → Selecting a mate able to protect family. - Solutions: o Psychical size. o Strength. o Social dominance/masculinity → Is associated with physical strength (underlining marker of high testosterone). ▪ Limited → If you completely masculinize a face then women don’t like it anymore. o Bravery. Do women prefer taller men? → Preference data from speed-dating. - For males the height of the woman doesn’t matter. - For females the height of the men do matter a lot → Women say yes more the taller the male is. o Height is a cue for someone that is strong and who can protect. - Women are said more yes to then men → Men are less choosier and more willing to say yes to a potential mate then women. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Leaders who can protect - The taller the president candidates were, the more votes the candidate got. - Thus taller candidates are more likely to be selected. Perceptions of dominant versus submissive individuals by opposite sex. - Videos of a man actor that was dominant and videos of a man actor that was submissive were played to females. o When the male actor showed dominance the sexual attractiveness of the man was rated higher than when it showed submissive behavior. o Also dating desirability was rated higher when the men showed dominance. o But when it turned into aggression or hostility the women did not like it anymore. - Videos of a female actor that was dominant and videos of a female actor that was submissive were played to males. o The female actor was considered to be sexual attractive no matter whether she was dominant or submissive. o Women acting very dominantly were rated a little bit less in dating desirability. Problem 4 → Selecting a mate who is healthy (and therefore remains alive long enough to continue investment). - Solutions: o Healthy-looking. o Psychical attractiveness. o Bodily symmetry. ▪ It basically says that the genes of this person created a body that underwent normal development where everything went right and symmetrical. Why preference for good health and psychical appearance? - Selecting an unhealthy mate is bad from an evolutionary perspective, because: o Increased risk of dying, therefore not investing. o May transfer communicable diseases. o Might infect the children. o A person who chooses an unhealthy mate would risk passing on genes for poor health to children. - We use make-up etc. to make us look better to deceive the opposite sex about our health. Problem 5 → Selecting a mate who is compatible. - Solutions: o Similar values. o Similar ages. o Similar personalities. o Similar education. - Relationships are more likely to succeed for a long time when you both are compatible. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Women’s characteristics as moderator of their mate preferences. - Women’s mate value: o Women with physical attractiveness and youth have a higher mate value because these are indicator of desirability to men (things men prefer). o Women with higher mate value prefer men who are higher in mate value. ▪ The type of mate value could be different for the sexes → An psychical attractive woman will end up with a man with high financial potential. - Women’s personal resources: o Evidence suggests that the more income women have the more they expect their partner to earn. The Amsterdam-problem - For every 73 men there are a hundred women in Amsterdam. - Even though there are not so much men to choose from because there are more women than man, the women will not lower their mate preference. o Lots of women are competing for a pool of relatively few guys. Social information: Mate copying. - Women rated a man when he was alone in the picture and then rated the man when other females were looking at him. - Men rated a woman when she was alone in the picture and then rated the women when other men were looking at her. - Results: o For men it did not matter → In both picture she was rated the same on the attractiveness scale. o For female it did matter → When the man was with other attracted members of the opposite sex (females), the man was rated more attractive. - Conclusion: o Women use more social information and engage more in mate copying. From preference to actual mating. - Do mate preferences actually predict the behavior of women? - Women’s preference are revealed by: o Response to men’s personal ads → Females response more to men that say they are financially independent. ▪ Men tend to stretch out more that they are looking for attractiveness and youth. ▪ Women tend to stretch out more that they are looking for a man with financial prospects. o Marriage to men high in occupational status → Men with a high status are getting married more often. o Marriage to men who are older → Females marry more older men. o Effects of women’s preferences on men’s behavior, desires, and drives ▪ Men compete via conspicuous consumption → Paying for dates to show financial prospects. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen ▪ Increased risk taking and ambition in presence of women → Showing bravery to the women. Why do men pursue a long-term mating strategy? - Women prefer men who are willing to commit. o Men who are unwilling to commit might fail to attract a mate. o In other words men don’t have a choice. - Increase in odds that he is the biological father. o Increased paternity certainty → Being committed to the relationship and be highly invested in the relationship enhances the chance that he is the biological father. - Increase in odds that his offspring survive. o It is important that his children also get children in order to give his genes to the next generation. o Investing in your children gives them a better chance to survive. Adaptive problems in long-term mating (likely more so for men) Problem 1 → Selecting a mate who has the capacity to bear children. - Solution → Preferences for qualities that are correlated with reproductive value: o Youth. ▪ That is why men prefer more younger women. ▪ A man chimpanzee does not prefer younger females but instead older female chimpanzees because chimpanzees have no menopause and older female chimpanzees have experience so chances are higher that his offspring will survive. o Health. - The reproductive value already starts to drop at the age of 20. Cues for fertility or reproductive value: - Full lips. - Clear skin. - Clear eyes. - Lustrous hair. - Long hair. - Muscle tone. - Sprightly gait. - Symmetry. - Facial femininity. - Feminine voice. - Low WHR. o The hip must be bigger than the waist. - Etc. - The cues for fertility are the same as the standards of attractiveness → Standards of female attractiveness are hypothesized to have evolved to embody observable cues to fertility or reproductive value. - Women can artificially alter these cues to make them look more youthful. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Cues to female attractiveness - Ancestral men had access to two types of observable evidence of a woman’s reproductive value: o (1) features of physical appearance, such as full lips, clear skin, smooth skin, clear eyes, lustrous hair, good muscle tone, and body fat distribution (low WTH ratio). o (2) features of behavior, such as a bouncy youthful gait, an animated facial expression, and a high energy level. Evolutionary theory of beauty - Standards of beauty emerge early in life → The standards are almost a fixed hardwire in our brain. o Young children already prefer to look at attractive faces than unattractive faces. o Not learned gradually through cultural transmission. - Standards of beauty are consistent across cultures. - Viewing attractive females distracts” men and activates nucleus accumbens (reward pathway of brain). Problem 2 → Selecting a mate who is faithful. - No man can say with 100% certainty that a child is his → Paternity uncertainty. - Solution → Preferences for qualities that are correlated with faithfulness: o Personality. o Youth. ▪ The younger the women is, the more likely she haven’t have any sex yet. o Reputation. Desire for having a mate that is a virgin. - In most of the countries males have a stronger preference for virgins then females. o In China and Sweden it is the female that prefer virgins a little bit more. - How important it is to have a mate that is a virgin also varies between the countries → Has maybe to do with mate competition. - This is in contrast with chimpanzees → Male chimpanzee want a older women who has more experiencing in raising her offspring. Mate guarding as evolved strategy. - To make sure the partner remains faithful. o In Muslim society women wear a veil → Could possible be a mate guarding strategy of the men. Men in long-term relationship: Trade-off between mating effort and parental effort → Testosterone as moderator. - Once a male becomes a parent, testosterone levels drop → Males start to invest in parenthood instead of looking for potential mates (sexual competition). - High testosterone means high sexual interest. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Conclusions: - Adaptive challenges facing… o Women long-term mating strategy: ▪ How to get an investing father. ▪ With resources. ▪ With willingness to commit. ▪ Ability to protect. o Men long-term mating strategy: ▪ How to become a father of successful offspring. ▪ Find a fertile partner. ▪ Find a faithful partner (to solve paternity uncertainty). - For both sexes → Similarity, kindness, and dependability attracts! Darwinian puzzle of homosexuality Darwinian puzzle of homosexuality - Heterosexual orientation prime example of a psychological adaptation. o Roughly 94 to 98 percent of men and 98 to 99 percent of women have a primary orientation toward heterosexuality. - Yet homosexuality is common in human and animal world, so there is a Darwinian puzzle. o Homosexuality basically means no offspring so how can it be passed on from generation to generation? - Is homosexuality an adaptation or byproduct? o Could it be that the trait homosexuality has evolved because it give some indirect benefit → Inclusive fitness. o Having a homosexual orientation you may benefit your siblings by investing more in their children. Evolutionary explanations for homosexuality: - Adaptive explanations: o Kin altruism theory: ▪ Homosexual men invest more in their kin (children of their siblings) → Instead of having their own children they invest in the children of the siblings to give them a better chance at survival. ▪ Mixed empirical support so far. o Alliance formation theory: ▪ Homoerotic behavior as strategy for gaining allies (“special friends”) (maybe with powerful men that will help you later on in life). ▪ Little empirical evidence. - Byproduct explanation: o Female fertility hypothesis: ▪ Genes for male homosexuality can be passed on if they produce an increased reproductive rate in the female relatives of male homosexuals → Pleiotropy. The genes for homosexuality in males lead to homosexuality. The same genes in the sisters of the homosexual males lead to increased reproductive rate. ▪ Strongest empirical support so far Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen o Older brother effect: ▪ Each older brother increases a male child's naturally occurring odds of having a homosexual orientation by 28-48%. However, the numbers of older sisters, younger brothers, and younger sisters have no effect on those odds. ▪ Maternal immune response system changes with each son. Strong empirical support. ▪ When a mother has carried more children, especially more sons, the quality of the uterus is somewhat deteriorated. Male embryos are more riskier to carry → Extreme masculinity is selected against. Younger sons are thus developed in a environment where masculinity is less → Less masculinized sons. What about non-heterosexual orientations in women? - Evolutionary basis of male and female homosexuality may be different. o Male homosexuality appears earlier in development. o Female homosexuality tends to be more fluid across life. - More research is critically needed. o Most of the research looks at male homosexuality because this is more exclusive than female homosexuality → Female homosexuality is more fluid. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Lecture 4 – Short-term sexual strategies The classic Clarke and Hatfield-study. - Imagine an attractive individual walks up to you on campus and says: Hi, I’ve been noticing you around town lately, and I find you very attractive. Would you have sex with me? o Females = 100 percent NO o Males = 75 percent YES ▪ Of the 25 percent that said no, they were apologetic, citing previous commitments for their declination. Then why don’t most men take the opportunity to go to the sperm bank to increase their reproductive success? - This has to do with how evolution works and how evolution has build our brains. - Evolution did not thought about the invention of sperm banks but it though about how can I make sure that these humans enjoy sex so much that they get children → Evolution has acted on the psychology of sex. Short-term mating Evolution produces psychological mechanisms for sexual desire (not for wanting babies per se). - Inputs (cues): o Access to potential mates. o Own mate value. o Costs of casual sex. - Mate preference mechanism: o Finding the “right” mate. o Sexual attraction. - Outputs (adaptive responses): o Falling in love. o Having sex. - Mate preference mechanisms lead to certain output like falling in love and having sex and these things could eventually lead to having babies. Short-term mating for men and women. - Men: o Almost all men want to go out with a woman even if they are slightly unattractive. o A little less men want to go to the apartment of the women but still a lot want it even if she is slightly unattractive. o Still more than half of the men would want to go to bed with a slightly unattractive female. - Women: o Women are still more selective than men when it comes to short-term mating. o For women attractiveness is more important than for men. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen o The majority of the female would go out with a exceptionally attractive man but only half of the women would go out with a slightly unattractive man. o Half of the women would go to the apartment of an exceptionally attractive man and only 12,9% of the women would go to the apartment of as slightly unattractive man. o Only 23,8% of the women would go to bed with an exceptionally attractive man and almost no women want to go to bed with a slightly less attractive man. Is a short-term sexual strategy an adaptation? - Do people in most cultures engage in casual sex? o It could be an adaptation if we would find evidence cross-cultural. - Are there specific contexts in which men and women pursue short term mating? - Is it reasonable to infer this for our ancestral environments? - Was there a potential benefit for ancestral men and/or women to engage in casual sex? Individual differences in mating strategy → The socio-sexual inventory. - Both among men and women there is variation. o This means that there is flexibility in the mating strategies. - Men tend to score higher on this test → Wanting more casual sex. Other great apes: Short-term or long-term mating? - The size of the testicles indicate the mating system in a species. - The size of the testicles says something about sperm competition → A marker of having a lot of casual sex. o Testicle size determines how much sperm you ejaculate and when there is a lot of casual sex, it is very important for the male to ejaculate a lot of sperm so the chances are higher that the female gets pregnant by him. - In species where there is a lot of casual sex, the males have larger testicles. o Bonobos → Have very large testicles and also have a lot of casual sex. o Gorillas → Have very small testicles because there is one alfa man that mates with a the females so there is no sperm competition. Physiological evidence for short-term mating in men. - Testicle size → Evolved due to sperm competition. o 0.079 percent of men’s body weight; ▪ somewhere between: 0.018 for gorillas (long term). 0.269 for chimpanzees (short term). o Researches say that humans are in between promiscuity (having more than one sex partner) and monogamy → So we may have some adaptations for short-term mating. - Variations in sperm production. o Sperm count increases with increasing amounts of time apart since last sexual encounter (even when controlled for time since last ejaculation). Mating strategies for males and females in animals: Battle of sexes. - Mating is cooperative because you need both sexes but there is also a lot of competition between the sexes because they want het best for their offspring. - For males it is about quantity → Get as much offspring as possible. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen - For females it is about getting the best dad (genes) for their offspring. o Some females will only mate with the strongest, best, biggest male. o Other females first mate with different males and then choose the best candidate. ▪ Chickens can squirt out sperm of males. - Males evolved ways to limit the females discretion. o In some species the males mate with brute force. o In some species the male follows the female so no other male can have sex with her. o Male squirrels can plug the females’ reproductive tracts with a fluid that hardens after sex so she cannot have sex with other males anymore. o Male fruit flies release a chemical that deactivates other sperm inside the female, stimulates ovulation and deactivates the sex drive of the female. - In response, females developed counter-counter strategies. o Some squirrel females know how to plug out the fluid that hardens after the sex. o Other species have a very complicated reproductive tract so only the male that is good in sex can really fertilize her → That is why some species have very weird penises. - In general → The more promiscuous the men are, the more choosier the female and the more intense the sexual arms raise. Theories of why men engage in short-term mating. - Adaptive Benefits for Men’s Short Term Mating. o High numbers of offspring. o Low parental investment. - So, under what conditions is short term mating an appealing option for (some) men? Poll question 1. Relative to men who pursue a long term mating strategy, men pursuing a short term mating strategy are predicted to ___________ women who might demand commitment or investment prior to consenting to sex. a. Avoid b. Find sexually attractive c. Pursue. d. Find repulsive. Answer - The right answer is A. Adaptative challenges for short-term mating for men Adaptive challenges for men who adopt a short-term mating strategy. - Possible psychological adaptations (solutions): o Increased interest in sex when meeting new partner. o Increased interest in sex with many different partners. o Be able to identify when women are (most) fertile. o Be able to feign commitment. o Reduced commitment after having sex. o Relaxation of standards when mating opportunities are limited → Lower their standards when there are less women. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen o Having many sexual dreams and desires. o Objectifying women. o Feeling regret over missed sexual opportunities. Main difference between men and women → How long do you need to know someone before you have sex? - A substantial portion of male already want to have sex after knowing the female for only 1 hour. - For females it takes a lot of time before they want sex with a male. How many different sexual partners would you like to have in the next month? - Men want a lot more different sexual partners in a month than women. - This is seen in a lot of different countries. Minimizing commitment after sex. - Attraction-reduction hypothesis: o Men with more sexual partners experienced a sharp decline in sexual attractiveness of partner immediately following intercourse. o Neither women nor men with less sexual experience show this decline. o Hasty Post copulatory Departure tactic. Closing time effect. - The later it gets in a bar (nearer to closing time), the more the males find the females attractive → Probably lowering the standards in order to not miss the opportunity of having sex. - This was corrected for alcohol intake. - Also the females start to find males more attractive when it is almost closing time. Which box would you remove when seeking a long-term mate versus a short-term mate. - Men who engage in short-term mating → Mostly want to look at the body of the women. - Men who engage in long-term mating → Mostly want to look at the face of the women. Sexual regret - Men → Feel more regret over missed sexual opportunities → Sexual omission. - Women → Feel more regret over sexual actions taken → Sexual commission. Behavioral evidence that men are, on average, more promiscuous. - Have more extramarital affairs. - Use more prostitution. - Use more social media and dating apps for sexual hookups. Costs for short-term mating But there are potential costs of short-term mating for men: - Contracting STDs. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen - Social reputation as “womanizer”(or being called a “slut” for women). o What label is worse, do you think, and why using evolutionary thinking → Being called a slut is worse because it basically says that the woman makes excessive potential costs and is not willing to invest in offspring. Being called a womanizer could actually be a good think when you only look at increasing the chances to get offspring. - Lowered chance of offspring surviving. o Helping with parental care also for fathers will increase the chances for surviving of your child. - Violence at hands of women’s family members. - Retaliatory affairs by wives. On the whole maybe the benefits of short-term mating for men outweigh the costs in certain environments and certain conditions. Costs to women of short-term mating: - Reputation as promiscuous. - Greater risk of physical and sexual abuse. - Becoming pregnant and rearing child alone. - Removal of resources by their current romantic partner when the woman sleep with other men. - Contracting STDs. Potential adaptive benefits of short-term mating strategy for women Lara Engelbert knowledge clip → Can women benefit from short-term mating? - Ancestral women could gain additional access to resources such as food by having sexual relationship with multiple men. - They also gained additional protection when having more than one man. - A women might be able to increase her social status by hooking up with high status man. - The short-term mate could potentially have better genes → Better offspring. - Having short-term partners enhances genetic diversity. - When the mate stops bringing in resources of becomes abusive, short-term mating strategy offers an alternative way to get rid of your current partner. - A short-term strategies might be useful to assess the suitability of a mate with regard to qualities, compatibility or potential hidden costs. - Engaging in short-term mating strategy can be the result of seeking revenge for a partner’s infidelity or it could be used to increase the commitment of the long-term mating partner by showing that other men are interested. Poll question 2. Which of the following characterizes most women who pursue short term mating strategies compared to women who pursue long term mating strategies? a. More feminine. b. More masculine. c. Lower preferences for facial masculinity in mates. d. Non of the above. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen Answer - The right answer is B. o Women have higher testosterone levels when they have short-term mating strategies → They copy the strategy of men. o The faces of the women that pursue short-term mating are more masculine than the faces of the women that pursue long-term mating. Potential adaptive benefits of short-term mating strategy for women. - Getting more resources. - Good genes for children. - Mate switching. - Mate skill acquisition. - Manipulation of current mate. Resource hypothesis - “Meat for sex” (in non human primates) →Females get food in return for sex so more partners means more food. - Paternity confusion (who is the daddy) → If you mate with multiple men and they all think they are the father, they will all invest in the offspring. o This happens in chimpanzees. - Extra protection (the “bodyguard” hypothesis). o A man cannot always be around to defend. o A second mate adds protection. - Elevated social standing by pairing up with a high status male. o In some cultures this is quite normal. - Evidence for resource hypothesis: o Women`s preferred qualities for a short term mate (Buss and Schmitt (1993): ▪ Extravagant life style. ▪ Spends money on gifts. Good genes hypothesis (good genes offered by superior men). - You already have a daddy who is committed and faithful and then have sex with someone else that has very good genes. - Enhanced Fertility → Fertility backup if regular mate is infertile or impotent. - Superior Genes → “Sexy son” hypothesis. o Hot guys will give you sexy sons (sons with the good genes). - Different Genes → Hedge against environmental change (incl pathogens). o In small scale societies it may pay off to have sex with someone outside the society to make the genetic pool more diverse → Makes your offspring more resistant to environmental changes. - Evidence: o Preferred mate qualities for short term male partner (Kruger et al., 2003; Sacco et al., 2012) ▪ Masculine. ▪ Muscular. ▪ Confidence. ▪ Dominance. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechtelijk beschermd, het verspreiden van dit document is strafbaar.  Stuvia - Koop en Verkoop de Beste Samenvattingen o Does the preference for masculine faces vary in women? ▪ When women are in their fertility phase, the women like more masculine men because this guy could potential give her good genes. ▪ Fertility and preference for dominant guys – VERY contentious. For a short-term relationship, the women have more preference for the dominant/masculine man when they are in their fertile phase. For a long-term relationship, the women don’t have more preference for masculinity when they are more fertile. There is a lot of criticism on this study. Contraceptives could possible influence mate preference away from the masculine guy towards the more feminine, investing, loyal guy. Adaptations for short-term mating in women → Signaling sexual interest. - Women are more likely to dress more sexually (picture B) when they are in their fertile phase → Possible signaling to men that they are fertile and try to increase the changes of getting a mate that could make them pregnant. Female orgasm as adaptation? - Female Orgasm does matter: o Retains more sperm (~5 percent) → More likely to conceive. o More likely to be orgasmic with affair partner than husband. - Women reported more frequent and earlier timed orgasms when mated to masculine and dominant men (as rated by observers). - Women reported more frequent orgasm when mated to attractive men (as rated by others). - There seem to be a biological mechanism (organism) in females that influences the likelihood of conceiving. - Experts still are investigating this. Mate switching hypothesis - Switching partners gives a signal to your partner that you are not happy with the relationship anymore. - When do women start an affair: o If a mate stops bringing in resources, starts abusing or otherwise declines in his value to her as a mate. o Mate expulsion → Having short term affairs would help the woman get rid of her long term mate. Mate skill acquisition hypothesis. - Short term mating as means to assess and evaluate prospective long term mates. o Allows a woman to: ▪ Clarify the qualities she desires. ▪ Evaluate her compatibility with a mate. ▪ Reveal hidden costs he might carry. Gedownload door: ypsalinasalgado | [email protected] Dit document is auteursrechteli