I. Genetic diversityII. HeritabilityIII. Genes for X’IV. Separating H and E influenceV. Selective breedingVI. Twin researchVII. Adoption studiesVIII. Genes and child developmentIX. Environment and gene expressionI. PersonalityII. TraitsIII. ReliabilityIV. ValidityEvidence that hippocampus is smaller in people with PTSD: “X causes Y”. Identical twins of such PTSD veterins also had relatively small hippocampi, even when they had never been in combat .Just a natural variationSmaller hippocampus makes you more susceptible to stress effects- it is actually Y that causes X! Volume-stress rxn party due to genetic variation.Parent’s genes may contribute to the environment a child finds itself inNiche seeking: who are the people, the attractions that welcome you? This is at least part of an expression of your genomeTwo kinds of identical twins:One placenta shared (monochorionic) or dichorionic (two placentas)Cat in the hat experiment: read cat in the hat to an infant after cat in the hat has been reading to prenatal infant, see if the infant shows recognition: it does. Prenatal learningIdentical twins exhibit phenotypic diversity even when they have identical histories of environmental exposure and genetic identicalness.Influence on environment on gene expression: epigenetics. Environment affects whether the gene is switched on and becomes activePups of high care moms are less fearful and less susceptible to effects of stress than the pups of low care momsWhen low care pups are raised by high care moms, they are less fearful than low care pups raised by low care momsEvidence that brain biochemical activity related to fear and stress responses can be altered by early experiencesGene for crime?People with the allele might be more likely to behave in ways that lead to some kinds of criminal behavior in some kinds of environments.Raine and Mednick: percentages of adopted males with criminal records as a function of biological father’s and adaoptive father’s criminal record statusHigher rate when the biological father has a criminal record, but also slight correlation in whether the adoptive father has a criminal record or not (also environmental influence)Personality (new PowerPoint):Trait: a disposition to reliably behave in a certain way under certain conditions. Usually regarded as continuous rather than categoricalMany traits can be produced by continuous variation along each axis (unstable/stable axis and introverted/extroverted axis)Eysenck’s two-factor model of personality: circle with labeled axes that categorizes personality traits. People don’t take it seriously because people believe that two factors are not enoughCentral trait creates surface traits (what you can observe)16 PF (personality factors): self-report questionnaireCattell, 1950. 18,000 trait-descriptive adjectives taken from a dictionary, then reduced to 170 basic ones, then get peer readings (large sample of undergraduates and get their peers to rate them), then by factor analysis of the peer ratings of adjectives, 170 is reduced to 16 basic dimensions of personalityEx: social – unsociable, shrewd – naïveFactor analysis: reduce the dimensionality of a set of data. How many underlying variables (latent variables, factors) are needed to account these data and patterns of correlations?Example of principle of parsimony: find the simplest explanation of a set of observationsThe factor structure was the same when measured in 6 different cultures, and they were the same as the US original – does not deal with questions about average trait values in different regions, countries, culturesPersonality structure: big five modelOpenness – non-opennessConscientiousness – undirectednessExtraversion – introversionAgreeableness – antagonismNeuroticism – placidity- Each factor has 6 specific traits/facetsNames of the scales and facets aren’t produced by a totally objective procedure such as factor analysis. More like reasonable/consensual labels for what the clustering test items are getting at.Reliability: stability over time, consistency across independent observersInter-observer reliability: how well do independent observers or judges agree about presence of absence of a trait?Validity: is the thing being measured meaningfully related to the underlying trait or behavior that it’s supposed to be an indicate of?A test’s validity coefficient can’t be greater than its reliability coefficientInformative: diagnostic, discriminates the two groupsScores on conscientiousness combined with SAT scores are a better predictor of GPA than SAT aloneTraits can differ in situations – are you the same with your friends as you are with your family?The MMPI (Minnesota multiphasic personality inventory) was designed to assess abnormal as well as normal dimensions of behavior.PSYC 100 1st Edition Lecture 13 Outline of Last Lecture  I. Genetic diversity II. Heritability III. Genes for X’ IV. Separating H and E influence V. Selective breeding VI. Twin research VII. Adoption studies VIII. Genes and child development IX. Environment and gene expressionOutline of Current LectureI. PersonalityII. TraitsIII. ReliabilityIV. Validity Current Lecture Evidence that hippocampus is smaller in people with PTSD: “X causes Y”. Identical twins of such PTSD veterins also had relatively small hippocampi, even when they had never been in combat .- Just a natural variation - Smaller hippocampus makes you more susceptible to stress effects- it is actually Y that causes X! Volume-stress rxn party due to genetic variation.  Parent’s genes may contribute to the environment a child finds itself in Niche seeking: who are the people, the attractions that welcome you? This is at least part of an expression of your genome Two kinds of identical twins: One placenta shared (monochorionic) or dichorionic (two placentas) Cat in the hat experiment: read cat in the hat to an infant after cat in the hat has been reading to prenatal infant, see if the infant shows recognition: it does. Prenatal learning  Identical twins exhibit phenotypic diversity even when they have identical histories of environmental exposure and genetic identicalness.  Influence on environment on gene expression: epigenetics. Environment affects whetherthe gene is switched on and becomes active Pups of high care moms are less fearful and less susceptible to effects of stress than the pups of low