PSYCH CHAPTER 4 NATURE NUTURE AND HUMAN DIVERSITY BEHAVIORAL GENETICS Study the differences and weight the effects that interplay heredity and the environment Genes Our Codes of Life oChromosome coiled chain of molecule of DNA that contain your genes oGene smell segments of DNA molecules that code for your individual oEnvironmental effects turn on genes When turned on create protein molecules that are the building block of physical development oGenome genetic profile that makes us humans Twin and Adoption Studies oIdentical vs Fraternal Twins Identical Genetically identical Do not always have the same number of copies of genes Most twins share a placenta but 1 of 3 have separate one s twin s placenta may provide better nourishment Fraternal No genetically similar than brothers and sisters Identical twins are more similar in mannerisms and personality Fraternal and identical twins are also more likely to become divorced because of similar life experiences oSeparated Twins Less identical personalities Same emotional physical and mannerisms oBiological vs Adoptive Relatives Adoption creates 2 groups genetic relatives and environmental Biological or not personalities are not similar Extraversion and agreeableness more similar to their biological relatives parents Environmental influences parents have an effect on some aspects beliefs values political views manners and faith Adoptive homes are less likely to become separated Adoptive children thrive and become more self giving and even intelligence than biological parents Temperament emotional excitability a persons stable emotional reactivity and intensity Twins have similar temperaments which assumes that heredity determines temperment Heredity predisposes temperament differences Biologically rooted temperament help form our enduring personality oTemperament and heredity o The extent to which variation among individuals can be attitributed to their if the difference of intelligence is 50 then it means 50 of the variation is due to genetics if all environments were the same the only variation would be due to heredity Heritability different genes oGroup Differences oNature and Nuture oGene Environment If an individual is predisposed to being aggressive this does not explain a group s aggressiveness The environment makes them aggressive Our adaptive nature enables us to be variant Our shared biology enables our developed diversity Genes not only code for proteins but respond to the environment Genes and environment always interact Genes are self regulating meaning that we can turn on and off genes making us adaptable to the environment Environments trigger personality Hyperactive child negative response from parents release of neurotransmitters that lead to depression As we grow older select environments similar to our nuture Genes and environment affect our traits individually but more important are their interactive effects An aggressive trait could evoke anger situationally Teacher and student example Genes affect how people react and influence meaning biological The New Frontier Molecular Genetics aspects have social influences oBottom up molecular genetics specify genes according to behavior Goal is to find some of the many genes that influence normal human traits such as body weight sexual orientation and extraversion and explore the mechanisms that control gene expression Psychologists and geneticists trying to pinpoint the genes of many diseases like depression schizophrenia etc instead of just identifying at risk individuals In order to pin point must seek links between chromosomes segments and specific disorders Could lead to a future where the genetic possibilities of a fetus can be revealed and possibly lead to a generation of missing children through selective abortion EVOLUTIONARY PSYCHOLOGY UNDERSTANDING HUMAN NATURE Behavorial geneticists explore the genetic and environmental roots of human differences environment o Study our differences and weight the relative effects of heredity and Evolutionary psychologists focus on what makes us so alike to humans evolution of behavior and mind in response to natural selection o Using Darwin s principle of natural selection we can understand the root of behavior and mental processes Organisms offspring competed for survival Certain biological and behavioral variations increase their reproductive and survival chances in their environment Offspring that survive most likely pass genes to next generation Thus over time population characteristics may change o Critiques Evolutionary psychologists take a behavior and work backward to explain it in terms of natural selection Need to test behaviors that explain evolutionary principles Evolutionary psychology proposes genetic determinism and undercuts morality in establishing society Remind us of how we have adapted not how we ought to be Where genders are unequal gender preferences are wide but when they are closely equal preferences narrow down Males and females are more alike than different so if we study differences and infer why they occured Natural Selection and Adaptation o When certain traits are selected and because they confer a reproductive advantage those traits over time will prevail Domesticated foxes ideal o Mutations advantageous variations that aid in survival o Our ancestral gene selection has aided us with the mechanisms to adapt to our environment because it is beneficial to survival Evolutionary Success Helps Explain Similarities o Behavioral and biological similarities arise Less than 5 of variation in the human genome occurs within groups 90 of variation comes from the differences between populations o Some genes have helped the success of reproduction Avoiding toxic bitter foods during pregnancy Avoiding leopard Those mothers that were more tending more likely to have successful offspring AN EVOLUTIONARY EXPLANATION OF HUMAN SEXUALITY Gender Differences in Sexuality o Perceive learn avoid predators but in reproduction we differ o Men have a greater sex drive than women o Research assignment where woman asked men to sleep with them and the men responded more positively than did the man o Men have a lower threshold of perceiving warm responses Think that friendliness is sexual interest Natural Selection and mating preferences o Women s approach to sex is more relational o Men s approach is more recreational o Women nurture 1 child while men impregnate many women this is what o Women pair wisely men pair widely o Men
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