Lesson 4 Psych PDF

 Chapter 4 Genes, Evolution, and Behaviour 1  What Makes You You? “I definitely got my curly hair from my mother and my skin complexion from my dad. I inherited my athleticism from neither!” Is it Nature or Nurture?  Do teens enga...

 Chapter 4 Genes, Evolution, and Behaviour 1  What Makes You You? “I definitely got my curly hair from my mother and my skin complexion from my dad. I inherited my athleticism from neither!” Is it Nature or Nurture?  Do teens engage in violence because the way their parents treated them as toddlers?  Are people naturally selfish/generous or aggressive/peaceful? What causes:  Differences in intelligence?  A tendency towards violence? 2  Chromosomes and Genes ___________________ Chromosome – Tightly coiled molecule of DNA – Contains many genes Genes ___________________ – Contain genetic blueprint – like a giant computer file of your characteristics, potentials and limitations Every cell has 46 chromosomes (23 pairs) Exception: _________________________ egg and sperm – Contain 23 chromosomes – Combine to form new cell with 46 chromosomes 3 Heredity encoded in combinations of bases adenine, thymine, guanine, and cytosine protein Genes contain bases, carry codes for ___________ manufacture (approx 70,000 in humans) 4  Chromosomes & Genes Genotype ___________________ – Specific genetic makeup – Present from conception – Never change Phenotype ________________ – Observable characteristics – Can be altered by other genes, environment – e.g. chickens still have genetic code for teeth Genotype 'can' grow how fall Ex how full you versus you. actually' grow 5 Phenotype  Dominant Gene _____________ – particular characteristic that it controls will be displayed _____________ Recessive Gene – characteristic will not show up unless partner gene inherited from other parent also recessive E.G. eye color – Brown eyes dominant over blue eyes 6 CLASP YOUR HANDS TOGETHER! 7  Can You Roll Your Tongue???? = Dominant l = recessive Ll roller LL roller Il non-roller If both parents can roll their tongues, is it possible for them to have children who are non-rollers? Yes I small Is , If both parents are non-rollers, is it possible for them to have children who can roll their tongues? No It Ih is If you can roll your tongue, does that mean that both of your parents can roll their 1 Al tongues? No 8 Cl + roller  Dominant, Recessive & Polygenic Characteristic displayed if: – Dominant gene from either parent – Two recessive genes (one from each parent) Polygenic transmission (multiple gene pairs ______________ influence phenotype) Complicates picture, but also magnifies # of possible variations in a trait 9  Genetic Engineering Recombinant DNA procedures ___________________ – Enzymes cut DNA – Combined with DNA from another organism – Inserted into host cell ___________________ Gene Knockout – Particular function of gene is eliminated Problems? - Few behaviours are controlled by single gene 10 - Ethical issues  Huntington's disease Neurodegenerative disease Symptoms first appear 30-45 yrs – after which typical lifespan 5-15 yrs Affects muscle coordination, cognitive decline, dementia Caused by single dominant gene – 50% chance of passing it on to children Genetic tests available to determine whether one carries the gene – Would you want to know? Genetic procedures available (in vitro) to ensure “HD” free genes in sperm/egg – Ethical? 11 Behavioural genetics Study of how behaviour is influenced by genetics For example - understanding genetic influence of: intelligence, alcoholism, addiction, schizophrenia, mood disorders How do we do this? Behaviour Genetics Techniques Study of genetic relatedness 50 – With parents = _____% 50 Siblings = _____%; 25 % Grandparents = _____ 13  Genetics and Humans Studies of twins & adoptees Concordance Rates – ________________– co-occurrence of a characteristic among individuals Adoption Studies – Look at correlations of various traits between adopted child and either biological or adoptive parents 14  Behavioural Genetics Monozygotic Dizygotic 15  Heritability ___________________ –How much variation is attributed to genetic differences within a population Ex heritability. for Weight is 0 6. or 60 % 60 % of the variation in weight we see –______ in the population is due to genetic differences 16  Heritability Facts About _______________ An estimate of heritability applies only to a particular group living in a particular ______________ environment Heritability estimates do not apply to __________, individuals only to variations within a group Even highly heritable traits can be modified by the environment similar group = Higher heritability 17 Diverse Lower Heritability group =  Genetic Influences on Behaviour Intelligence – To what extent are differences in intelligence due to genetics and what extent does environment determine intelligence? If it is completely controlled by genes: People with the same genes should have __________ More important question – How do genes and environment interact? 18  Reaction Range ____________________ – Range of possibilities - upper and lower limits - that the genetic code allows – Environmental effects determine where person falls within these limits – Reaction range may cover as much as 15-20 IQ Environment t us el wherearange points 19 Behaviour genetics & Minnesota Twin Study Is there a genetic component to personality? To intelligence? Genetic contribution Need to study Shared family environment Unique individual experiences 20  Minnesota Twin Study Assessed >400 pairs of twins (reared together and apart) Median age separated =2.5 mos Genetic factors accounted for 39-58% of variation Unique experiences accounted for 36-56% of variation Familial environment little or no accounted for___________ variation 21  Identical twins raised together higher than raised apart Rules out entirely genetic explanation Heritability for Intelligence? 50 70 % of variation b/w people – genetics accounts for ________ - 22  Other Research Attitudes have an inherited component ______________ – preservation of life, equality, athleticism - highest genetic component – Certain inherited characteristics (e.g. physical characteristics such as development of vestibular system) may predispose people to certain activities 23 Evolutionary Psychology 24  Evolution & Behaviour Evolutionary Psychology ________________________ – How behaviour & tendencies have evolved in response to environmental demands What is evolution? – Change over time in frequency with which genes, & characteristics they produce, occur within an interbreeding population Mutations ________________ – Create genetic variations, making evolution possible – Can be passed to offspring 25 Legacy of Darwin Natural Selection ________________ If trait gives some members a competitive advantage (attract mates, escape danger, acquire food) – more likely to survive and pass on their genes 26  Evolution of Learning Tryon (1934) Selective breeding of maze-bright and maze- dull rats Measured # of mistakes made be each rat Bred “bright” males with “bright” females, “dull” males with “dull” females 27  Human Adaptions Bipedal locomotion Development of tools, weapons Social organization (________________________) specialized roles-males and females Change in brain structures (e.g. ability to learn language, repeat beh’rs that are rewarded and suppress those punished, choosing safe foods to eat, form cooperative alliances) 28  Evolution of Human Brain Greatest growth in areas concerned with higher mental processes - attention, memory, thought, language 29  An Evolutionary snapshot language Innate ability to acquire ____________ Newborns prewired to receive specific stimuli Need to belong to a _____________ group emotions Some basic ______________ seem universal 30  Mating Systems & Parental Investment The Evolution of Desire – Have we evolved patterns for choosing a mate? Parental Investment ___________________ – Time, effort, energy, risk associated with caring successfully for each offspring – Humans invest a great deal in small # of offspring – Other species produce large # of offspring & offer little care – Trivers (1972) – sex differences in parental investment explain mating systems 31  Mating systems Polygynous ________________ (most common in mammals) – Females > males in parental investment – One male; many females – More polygnous the species – the greater size difference b/w + Monogamous ___________________ (90% of all birds) – Two parents have equal parental investment – Little sexual dimorphism between males/females 32  Mating systems Polyandrous _________________ (rare in mammals, occurs in some fish & insects) – One female - many males – Females compete for access to males – Sexual dimorphism - female stronger, more aggressive Polygynandry _________________(chimpanzees) – Promiscuous relationships among males / females 33  What do men & women want? Men & Men Women women Physical Mutual attraction attractiveness , Earning Potential , Health Status , ambition Dependability Emotional stability 34  The ideal mate - worldwide! Women - Older (around 3 years) - High parental Investment - Symmetrical face (indicative of health) Men - Youth & Health - Clear Skin, animated facial expression , high energy level Bouncy youthful guit , , 35  La Cerra Study Do women have preference for men who show signs of high parental investment? Showed female undergrads pics of males in 5 conditions and asked to rate attractiveness as potential mate Standing alone Highest Smiling & playing with child Ignoring crying child lowest Standing beside child (neutral) Vacuuming 36  Social Animals Help One Another Cooperation ____________________ – One individual helps another and gains some advantages – E.g., cooperating to achieve a goal Altruism __________________ – One individual helps another but there are costs involved – E.g., putting oneself in danger to help another – Does this make sense evolutionarily?? 37  Evolutionary Psychology Kin Selection 1. _________________ – Behaviors that help genetic relatives may be favored by natural selection Having offspring isn’t the only way to ensure your genes are passed to future generations – Help relatives – who share some of your genes - produce offspring 38  Explaining Altruism Reciprocity hypothesis 2. _____________________ – A helpful action is repaid at a later date by observers of the helpful individual 39  Aggression Adaptive purpose for aggression (evolution) – Certain physical & beh’l attributes selected for – Divide limited resources (food, mate, territory) – Forming social alliances Dominance Hierarchy _______________________ – Can serve to quell aggression – Set access to resources 40 Coalitions & Aggression Only 2 species form coalitions for the purpose of lethal aggression against others Humans · Chimpanzees and 41