Textbook Notes (367,907)
Canada (161,488)
Psychology (4,882)
Psychology 1000 (1,620)
Dr.Mike (707)

4 - Genes, Evolution and Behaviour.docx

15 Pages
Unlock Document

Psychology 1000

Chapter 4 Genes Evolution and Behaviour 1 Genetic Influences  Genetic endowment + environmental forces  behaviour  Nature (something we are born with) vs nurture (something we learn) o Environment can influence protein synthesis o Genes determine range of possibilities but not the degree of expression Chromosomes and Genes  Hippocrates suggested that semen contains some sort of design for offspring  Mendel used garden peas o Show heredity involves passing on specific organic factors  Genotype: set of genes inherited  Phenotype: observable characteristics produced by that genetic endowment o Can be affected by other genes and by the environment o Cannot infer genotype from phenotype  Chromosome: tightly coiled molecule of DNA that is partly covered by protein  Genes: DNA portion of chromosomes that carry the hereditary blueprint  Alleles: alternative forms of a gene that produce different characteristics  There are no genes for a particular attribute o Measure of intelligence = measure of reaction time (fast response of neurons = ↑ intelligence?) Dominant, Recessive and Polygenic Effects  Genotype and phenotype are not identical because some genes are dominant and others are recessive  Dominant: particular characteristic that it controls will be displayed  Recessive: characteristic will not show up unless both genes inherited are recessive  Polygenic Transmission: number of gene pairs combine their influences to create a single phenotypic trait  Homozygous Allele: phenotypic outcome predictable  Heterozygous Allele: phenotypic outcome may not be predictable Genetic Engineering: The Edge of Creation  Recombinant DNA procedures: certain enzymes cut DNA into pieces & combine them with DNA from another o Produced the human growth hormone  Insert new genetic material into viruses that can infiltrate neurons and modify their genetic structure  Gene Knockout: alter a gene in a way to prevent it from carrying normal functions o Test animals to see if neurons did not respond to neurotransmitter, what will it affect? o Disadvantage: very few behaviours are controlled by a single gene Behaviour Genetics Techniques  Heritability coefficient: variation in a characteristic within a group can be attributed to genetic factors o Applies to within a group and not between groups as different factors affect different groups o h = variance due to genes / total variance o h = 0.0 (due to environment diversity) = 1.0 (due to genes, genetic diversity) o does NOT indicate extent to which genes are responsible for expression of trait o hair colour in inuit  everybody has that hair colour in the population  genes are responsible for the trait but no variability  heritability is 0 (due to environment)  Family relationship studies  Concordance: (co-occurrence) characteristic o Identical twins 100% o Fraternal twins, parents, siblings 50% that has higher co-occurrence in highly o Grandparent, uncle, aunt 25% related people o First cousin 12.5%  Adoption Study: study if adopted child if more similar to biological or adoptive parent 2  Twin Studies: monozygotic (identical twins) and dizygotic (fraternal) growing up in different environment  Galton: Hereditary Genius o Assumed that intelligent successful men had intelligent successful sons  But not the same for intelligent successful men and adopted sons  Measures simple motor and sensory abilities  Believes that intelligence was unitary (mental quickness)  Invented correlation coefficient  Results disappointing - didn’t find correlation  Sir Cyril Burt o Large sc2le study of twins reared apart in separate environment o Reports h approaching 1.0 (genes) but faked data  Bouchard’s Twin Studies and finding long lost twin o Identical twins, apart 0.72 2 o Identical twins, together 0.86  H = 0.72 o Fraternal twins, together 0.60 o Not saying that IQ is genetically determined o Siblings, together 0.47  Of the observed variability in measured IQ, we can o Adopted sibs, together 0.34 o Same person 0.87 attribute to 72% genetic factors  Scarr and Carter – Saltzman (1979) o Important assumption  No environmental differences for identicals vs fraternals  Treat identicals different than fraternals o Twins who thought they were identical (whether true or not) were more alike o Twins who though they were fraternal (whether true or not) were less alike Genetic Counselling  Provides counselling, support and medical information about genetic disorders and risks to patients and families  Good to test and monitor diseases, pregnancy, new born What is the cause of genetic disorders? Single Gene Disorders o Enlarged ventricles, cortical  PKU degeneration o Recessive gene on autosome 12 o Dominant  offspring has 50% chance o Occurrence: 1 in 10,000 of acquiring o Lack enzyme; phenylalanine  tyrosine o Detection possible through gene o brain damage  mental retardation mapping o Effectively treated by diet  Tay Sachs Disease Sex-linked disorders o Recessive gene on pair 15  Men are more susceptible than women because o Occurrence: 1 in 3600 (Eastern Europe) y chromosome is shorter (less information) o Lack enzyme to break down fatty acids  XXX, Xy, Xyy – phenotypically male o Normal development at birth  Blind, deaf, unable to swallow, Down syndrome (chromosomal mutation in meiosis) muscle atrophy, mental damage  Nervous system abnormality  retardation  Fatal by age 4  Physical appearance (mongolism)  Huntington’s  Due to accumulation of amyloid protein (also in o Rare dominant gene on autosome pair 4 Alzheimer’s) o Occurrence: 1 in 16 000 o Plaques and neurons die o On set 35 – 45 years o Can alleviate symptoms with intense  At first: clumsy, forgetful cognitive stimulation  Progressive deterioration:  Incidence related to mother’s (and dad’s) age muscle control (chorea), I.Q., o Risk about 1 in 1000 brain, terminal in 10 – 20 years o Past 40, 6 in 1000 3 Genetic Influences on Behaviour Heredity, Environment and Intelligence  differences in intelligence due to genetic factors and environment  Genetic argument o The more genes people have in common, the more similar they are in IQ  Environment argument o Twins and siblings raised together have more similar IQs Biological Reaction Range, the Environment, Personality and Intelligence  Reaction Range: genetically influenced trait is the range of possibilities  one inherits a range for potential intelligence and environment will determine where they are in the boundaries Behaviour, Genetics and Personality  Hans Eysenck was the first modern personality theorists o Personality differences could be traced to differences in brain development or function  Five Factor Model – personality trait theory of Robert McCrae and Paul Costa o Extraversion-Introversion (sociable, outgoing, adventuresome vs quiet, inhibited, solitary) o Agreeableness (cooperative, helpful, good-natured vs antagonistic, uncooperative, suspicious) o Conscientiousness (responsible? goal directed? dependable? careless?) o Neuroticism (worrying, anxious, emotionally unstable vs well adjusted, secure, calm) o Openness to experience (imaginative, artistically sensitive vs unreflective, lacking in intellectual curiosity)  Identical twins may be more alike o People treat them the same o Parents dress them up in identical clothes  Identical twin experiment where they are raised in different environments o Variation attributable to genetic factors o Variation due to a shared family environment among those reared together o Variation attributable to other factors due to unique individual personal experiences o Proven that they are more similar even raised in different environments o Genetic factors and individual experience most influenced o Twins have heritability coefficients all greater than 0.5 Conclusion  Genetic, environmental and personal experiences are all equally important to personality characteristics The Neuroscience and Genetics of Dyslexia  Dyslexia: difficulty learning to read  Genetic contribution to the entire range of reading ability  Spelling and phonological coding (ability to translate letters and syllables into sounds)  Specific dyslexia susceptibility gene on chromosome 6  Chromosome 1, 2, 3, 6, 15 and 18 influence reading ability o Not a sex-linked disorder  Gene variants associated with dyslexia influence brain development and later brain function o Hard to do experiment  Reading out loud does not mean you are reading the word right  Reading silently, uncertain if you read it correct in your head  Less activation that controls in two area of the left temporal lobe 4 Evolution and Behaviour  Evolutionary psychology - how behaviour have evolved over millions of years in response to environment o no behaviour can occur without environment impacting Evolution  1 day = 9.6 million years  Mid nov – vertebrates  11:54 on 31 – homo sapiens  Jan – life begins  Dec 11 – mammals  Overall, we haven’t been  Feb-oct – nothing much  19 - birds around for a long time happening  Dec 24 – primates Darwin  He didn’t want to publish his discovery o Humans were related to apes and other creatures in the world Evolution of Adaptive Mechanisms Evolution  change over time in number of particular genes and characteristics they produce in an interbreeding population  some genetic variations through mutations, random, accidents during mitosis  mutations help create variation and variation is needed for evolution Natural Selection  characteristics that increase the likelihood of survival and ability to reproduce within a particular environment o more likely to survive and become more common over time  neutral variation/evolutionary noise (random variations) is preserved for future environmental demand Evolutionary Adaptations  products of natural selection  allow organism to meet recurring environmental challenges to their survival, thereby ↑ reproductive ability  organism’s biology  behavioural capabilities and its behaviour (mental abilities)  whether it will survive  theory 1 o forced apelike animals from trees to hunt on open plains o survival greater for bipedal locomotion (walk on 2 legs) o freeing their hands to use as weapons o hunting encouraged social organization o language developed o Australopithecus (early ancestor)  homo erectus  Neanderthal  Brain size tripled o domain specific adaptations: designed to solve a particular problem  human brain is all purpose problem solver  Proximal vs distal causes Distal  Proximal o Proximal – immediate, what causes behaviour now  Evolutionary history of species o Distal – evolutionary process  Distal  Individual DNA  Inherited traits o Very functional – changing to meet environmental needs  Social development  Ultimately everything is due to the genes but  Emotional reaction info processing  Phenotype does not mean genotype  Traits not necessarily due to natural selection (psychology – closer to proximal)  Phenomenological experience  No natural selection o Genetic drift  Founder effect… chance (geographic)  Restricted gene pool of species (e.g. due to migration) o Correlates of structure - other related trait selected 5 An Evolutionary Snapshot of Human Nature  Language – infants exposed to language at a younger age  human bonding with caregiver – recognize human faces  need to belong – make cooperative relationships with a group became critical to survival & reproductive success  helpful – altruism increases with degree of genetic relatedness  emotions – social communication  personal adaptations to life – learning & experience Evolutionary Psychology Personality  Evolutionary Personality Theory: how biological factors contribute to diff between personality traits o Extraversion, emotional stability helpful in mate selection o Conscientiousness and agreeableness important to group survival and reproduction o Openness to experience for problem solving and creative activities Mating Systems and Parental Investment  Produce lots of offspring and offer little or no care E.g. fish  Produce few offspring, offer care, protection until independently survive on their own E.g. humans, mammals  Parental Investment: the time, effort, energy and risk associated with caring successfully for each offspring o Sex with more investment is more discriminant and more competed for o Sex difference – egg and sperm, pregnancy and breast feeding o Polygyny: more than one wife  More female investment and polygyny  Male investment low to maximize fitness to reproduce with different females  Species with more polygyny are larger males relatives to females  Females are more discriminating since they have limited eggs o Monogamous mating system: equal or approximately equal parental investment e.g. birds  Natural selection would favour genes that lead to parents staying together  Both parents investment leads to lower competition o Polyandry: one female mates with many males (rare)  Females are larger and more aggressive than males since they are competing for their mates o Polygynandry: (promiscuity) all members of the group mate with all other members eg. chimpanzees  Can help reduce competition for a mate Mate Preference  Both genders - mutual attraction, dependability and emotional stability  Men - emphasize more on physical attractiveness (consistent in every culture) o Good hea
More Less

Related notes for Psychology 1000

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.