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Module 11 and 12 - October 28, 2013.docx

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PSYC 1010
Heather Jenkins

module 11 - behavior genetics and evolutionary psychology behavior geneticists study our differences and weight the effects and interplay of heredity and environment geneticists and psychologists are interested in the occasional variations found at particular gene sites in human DNA genes - segments of DNA that contain instructions to make proteins genetic: DNA - is a double helix spiral - every cell has 46 chromosomes (23 pairs) -exception: egg and sperm contain 23 chromosomes each and they combine to form a new cell with 46 chromosomes genes can be active (expressed) or inactive environmental events (every nongenetic influence, from prenatal nutrition to the people and things around us) turn on genes and when they are turned on, they provide the code for creating protein molecules - our body's building blocks we share about 96 % of our DNA with chimpanzees how genes work -genes are not blueprints, they are molecules -these molecules have the ability to direct the assembly of proteins that build the body -this genetic protein assembly can be turned on and off by the environment, or by other genes -any trait we see is a result of the complex interactions of many genes and countless other molecules. chromosomes and inheritance chromosomes are threadlike structures made of DNA molecules that contain the genes one chromosome of every pair is from each parent each nucleus contains 46 chromosomes, arranged in 23 pairs each human cell (except red blood cells) contains a nucleus the human body contains 100 trillion cells. human genome project - scientists working to understand our own genetic makeup material - found about 25, 000 genes but expected to find more - found more than 200 bacteria... - found more than 75 genes that contribute to hereditary diseases genotype - specific genetic makeup (DNA analysis) - present from conception. as soon as mother and father come together that's your genotype phenotype - observe characteristics - if you are male or female, eye color height, etc. - the physical expression of your genotype dominant, recessive, and polygenic - so why arent genotype and phenotype always identical? - Dominant - Capital letter - Recessive - little letter characterisic displayed if -dominant gene from either parent -two recessive genes (one from each parent) -polygenic transmission (multiple gene pairs influence phenotype genetic engineering - ex genetically modified food products recombinant DNA procedures - -combined with DNA from another organism and inserted into a host cell gene knockout - particular function of gene is eliminated by preventing neural response to a particular neurotransmitter problem - there are very few behaviors that are controlled by a single gene - knocking out a particular gene could disrupt a wide range of functions behavioral genetics - can we design an experiment to keep genes constant and vary the environment and see what happens? Or can we vary the genes in the same environment? study of genetic relatedness heritability coefficient - estimate of how much characteristic is due to genetic factors ADOPTION AND TWIN STUDIES adopted children are frequently more similar to biological parents identical twins are more similar even when they are reared apart monozygotic (zygote splits) twins identical chromosomes - identical twins dizygotic (two separate eggs fertilized by 2 separate sperm) twins different chromosomes - fraternal twins study of genetic relatedness - with parents - 50% -siblings 50% -grandparents 25% heredity - passage of characteristics by way of genes heritability- how much variation is attributed to genetic differences heritability coefficient - estimate of how much of characteristis is due to genetic factors concordance rate - rate of co-occurrence of a characteristic among individuals - higher rates among individuals who are more highly related to one another =possible genetic contribution identical vs. fraternal twins - identical twins are much more similar than fraternal twins when it comes to personality traits such as extraversion and neuroticism - behaviours/outcomes such as the rate of divorce, occupations greater in identical twins than fraternal twins - abilities such as overall intelligence test scores studies of identical twins raised apart it is thought that tongue rolling is controlled by one allele on one gene. genetic influences on behaviors intelligence -is it genetics or environment the more important question is how do genes and environment interact? Are there genetically determined boundaries on the expression of a trait? reaction range - the range of possibilities - upper and lower limits - that the genetic code allows -the individual inherits a range for the potential expression of a trait -environmental effects determine where the person falls within these limits are there genetically determined 'boundaries' on the expression of a trait? Graph - If there is an environment that boosts intellectual things and academic performance like access to books etc, u have an enriched IQ than those who don't have that type of environment deprived - low IQ because of lack of enriched environment average - individuals have an average IQ enriched - top of genetic possibility of IQ An enriched environment gives the individual the opportunity to develop their intelligence. A deprived environment limits their intelligence to the lower ranges parenting effects: biological vs. adoptive relatives genetic relatives - biological parents and siblings environmental relatives - adoptive parents and siblings studies have been performed with adopted children for whom the biological relatives are known findings - adopted children seem to be more similar to their genetic relatives than their environmental/nurture relatives. does parenting/nurture make any difference? does the home environment have any impact? yes parenting matters. despite the strong impact of genetics on personality, parenting has an influence on: religious beliefs, values, manners, attitudes, politics, and habits If parenting has an influence, why are siblings so different? -siblings only share half their genes -genetic differences become amplified as people react to them differently -siblings are raised in slightly different families; the youngest has more older siblings and has older (wiser? more tired?) parents behaviour genetics and personality - is there a genetic component to our personality? you need to study -genetic contribution -shared family environment - studies from adoptive families find that people who grow up together whether biologically related or not do not much resemble one another in personality -unique individual experiences How can we study this? through identical twins reared together and apart AND fraternal twins reared together and apart. temperament is another difference not caused by parenting from infancy into adulthood, most people do not seem to change temperament (defined as a person's general level and style of emotional reactivity) Our biologically rooted temperament helps us form our personality According to some researchers, three general types of temperament appear in infancy: - easy (relaxed happy baby, not angry all the time, sleep well, not frustrated) - difficult (hard to calm down, quick to being upset, disrupted sleep patterns) - slow to warm up (take a little while to get comfortable and easy, little bit more withdrawn or stand offish unless they get to know you, but they get easy) molecular genetics - is the study of the molecular structure and function of genes seeks to indentify exactly which specific genes influence behavior genetic tests can reveal which people are at risk for many physical diseases (like learning disabilities, depression, schizophrenia, and alcohol dependence) and may soon identify people at risk of mental health disorders they find families that have had the disorder across several generations and draw blood or take cheek swabs from both affected and unaffected family members and examine their DNA looking for differences ethical conundrum - should people use genetic tests to select sperm, ,eggs, and even embryos for health, brains, or beauty? genetic counseling -what do genetic counselors do? they provide medical information about genetic disorders and risks they help individuals make decisions about their health, pregnancies, or their child's health care nature and nurture working together: interaction of genes and our environment some traits, such as the overall design of our bodies, are set by genes other traits, such as physical and mental abilities, develop in response to experience How does the interaction of genes and environment work? -genetic traits influence the social environment, which in turn affects behavior -->environment (physical, social, cultural)--> behavior --> neural activity --> genetic activity -self regulation - genes turn each other on and off in response to environmental conditions -epigenetics (studies the molecular mechanisms by which environments trigger genetic expression) - the environment acts on the surface of genes to alter their activity evolution and behavior the trait of being adaptable is built into the human genome -paradox - our genes allow us not to be tied so much to our genes! -we have minds which allow us to change our behavior in response to the environment to a greater degree than other species -we even shape our environment to suit our nature -humans can adapt to a variety of climates, diets, lifestyles, and skills evolutionary psychology - how behavior and tendencies have evolved in response to environmental demands using natural selection What is evolution? It is the change over time in frequency with which genes and the characteristics they produce occur within an interbreeding population Mutations create genetic variations, making evolution possible and can be passed to offspring begin with a species genome, which contains a variety of versions of genes that shape traits our behavioural and biological similarities arise from our shared human genome - our common genetic profile adaptations - products of natural selection allows organisms to meet environmental challenges to their survival ex - bipedal locomotion - we can pick things up with our hands and throw them (development of tools/weapons) - this adaptation puts us ahead of certain things -we get social organization, language, culture (hunting groups) - our brain structures have changed because we have been adapting through things types of adaptations broad - learn language, reason logically domain-specific - solve particular problems -mate selection -choosing safe food -avoiding certain environmental hazards This suggest that the mind is composed of specialized and independent modules Common aspects of Human Behavior - An evolutionary snapshot -innate ability to acquire language -newborns are more responsive to human faces -need to belong to a group -some basic emotions seem universal evolution of human brain - there is greatest growth in areas concerned with higher mental process like attention, memory, thought, language important - environmental input to evolutionary mechanisms (role of culture) brains - Australopithecus, homo erectus, Neanderthal, homosapiens personality- Evolutionary personality theory - limited # of dimensions to personality - found universally (extraversion , emotional stability, conscientiousness, openness to new experiences) help us to achieve2 goals - survival and reproduction mating systems and parental investment - the evolution of desire - have we evolved patters for choosing a mate and rearing our children? parental investment - time, effort, energy, and risk that is associated with caring successfully for each offspring females usually have competition for the male with the highest parental investment male and female differences are focused on mating preferences - quantity of mating (generally, men think more about sex than women, and men are more likely to think that casual sex is acceptable) - men who had the trait of promiscuity were more likely to have their genes continue and even spread mating systems - Trivers (1972) believed that sex differences in parental investment explains mating systems two parents do not necessarily make equal parental investment - penguins - little sexual dimorphism between males/females monogamy - one male, one female polygynous- one male, many females - lions - greater sexual dimorphism in size/strength between males/females - females more discriminating in choice of mate -males compete for access to females polyandry - one female many males - females compete for access to males sexual dimorphism - female stronger more aggressive polygynandry - many males and many females possible evolutionary strategies in seeking partners - how would evolutionary psychology explain why males and females have different preferences for sexual partners? what do men and women want in an ideal mate? men seek women with a fuller figure to make sure they are not too young or too old to have children -that is young and healthy (reproductive potential) -symmetrical face women seek males with loyal behavior and physical and social power and resources in order to ensure the survival of the mother's offspring -should be older (about 3 and a half years older) - symmetrical face (indicative of health) - high parental investment For both men and women the top 3 things in preference are - mutual attraction, dependability, emotional stability module 12 - culture, gender, and other environmental influences how does experience/the environment shape who we are and affect brain development? genes expressed in different environmen
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