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 LifeoChromosome: coiled chain of molecule of DNA that contain your genes oGene: smell segments of DNA molecules that code for your individualoEnvironmental effects “turn on” genes When turned on, create protein molecules that are the building blockof physical developmentoGenome: 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 divorcedbecause of similar life experiencesoSeparated Twins Less identical personalities Same emotional, physical and mannerismsoBiological vs. Adoptive Relatives Adoption creates 2 groups: genetic relatives and environmental relatives Biological or not, personalities are not similar Extraversion and agreeableness more similar to their biological 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 parentsoTemperament and heredity 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- Heritabilityo The extent to which variation among individuals can be attitributed to their different genes 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 toheredityoGroup Differences If an individual is predisposed to being aggressive, this does not explain a group’s aggressiveness The environment makes them aggressiveoNature and Nuture 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 environmentoGene-Environment Genes and environment always interact Genes are self regulating, meaning that we can turn on and off genesmaking us adaptable to the environment Environments trigger personality - Hyperactive childnegative response from parentsrelease 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 aspects have social influences- The New Frontier: Molecular Genetics 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 abortionEVOLUTIONARY PSYCHOLOGY: UNDERSTANDING HUMAN NATURE- Behavorial geneticists explore the genetic and environmental roots of human differenceso Study our differences and weight the relative effects of heredity and environment- 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 changeo CritiquesEvolutionary 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 whenthey 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 Adaptationo When certain traits are selected and because they confer a reproductive advantage, those traits over time will prevail Domesticated foxes idealo Mutations: advantageous variations that aid in survivalo Our ancestral gene selection has aided us with the mechanisms to adapt toour 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 populationso Some genes have helped the success of reproduction Avoiding toxic, bitter foods during pregnancy Avoiding leopard Those mothers that were more tendingmore likely to have successful offspringAN EVOLUTIONARY EXPLANATION OF HUMAN SEXUALITY- Gender Differences in Sexuality o Perceive, learn, avoid predators, but in reproduction we differo Men have a greater sex drive than womeno Research assignment where woman asked men to sleep with them and themen responded more positively than did the mano Men have a lower threshold of perceiving warm responses Think that friendliness is sexual
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