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PSYC 332
Richard Koestner

PSYC 332­ Introduction to Personality  McAdams Chapter Notes (Chapters 6 – 11) th For Final Exam (April 17 6:00 pm) CHAPTER 6 Continuity and Change in Traits: The Role of Genes, Environments, and Time Your life circumstances certainly change between the ages of 18 to 28 (high school reunion example) but do we change? Example of positive change: MaryAnne Cromwell- she used to be skinny and unpopular but came back 10 years later as a successful bombshell who attracted all the men. What was striking was her poise and assertiveness (which she obviously didn’t have before)- everyone was stunned by how much she had changed. Counter-example: McAdams’friend RobertAmundson hadn’t changed at all- he was the center of attention as he always had been. In HS McAdams described him as: socially dominant, outgoing, spontaneous, and NOT conscientious. It appears he hadn’t changed and was still socially dominant. For the most part Continuity in personality was the norm Most people seemed the same in terms of their: social mannerisms, modes of relating to others, the way they spoke, and things they spoke about Questions: do people’s dispositional traits change over time or do they remain constant? Where do personality traits come from? Genes? Environment? THE CONTINUITY OFTRAITS Attributing a trait to a given person implies that the trait has ‘staying power’ How long it will stay, however, is unclear One week is a safe bet, years later, we can’t be sure Psychologists expect trait scales to show high test-retest reliability in short-run TWO KINDS OF CONTINUITY 1)Absolute continuity: defined by Caspi (1998) ‘constancy in quality or amount of an attribute over time (literally receiving the same score on a given trait 10 later) - Not usually applied to single individual but group averages on given trait - Measure entire group on a trait, then again 10 yrs later, and see how much absolute continuity the group maintained. - Important in testing hypotheses about human development: ex. see if people change much after HS Could say that there isn’t absolute continuity in this developmental period McAdams would have predicted drop in social anxiety and increase in friendliness as a group (for his HS graduating class) from ages 18 to 28 2) Differential continuity: consistency of individual differences within a sample of individuals over time, to retain relative placement of the individual in a group Ex. Relative to his peers: Robert was and still is high on social dominance DC is about someone’s standing on a trait, relative to their peers For there to be high DC everyone must keep their place relative to the group Calculated using correlation coefficient: calculated between same individuals’scores on same trait at time 1 and time 2 High R suggests high DC, low R suggests low DC PSYC 332­ Introduction to Personality  Low DC suggests that people’s relative positions on given dimension change unpredictably over time – people change relative to one another on a given trait Low DC does NOT tell us about the direction of change The two types of continuity are completely unrelated to each other: AC- consistency of average score on given trait over time DC- stability of individual differences in their scores High AC does not mean high DC Hypothetical Situations Low High Outcomes - AC & Group average remains the same and everyone DC keeps their relative positions AC DC Group average changes (either up or down) but relative positions stay the same DC AC Group average is stable but relative ranks change AC & - Example: personal income- it will definitely go DC up between ages 18 and 28 BUT people may not keep their same ranks DIFFERENTIALCONTINUITY IN THE ADULTYEARS Most informative research on topic of whether traits remain consistent has been done in the adult year via longitudinal study Longitudinal study: researchers follow same group of individuals over time to chart continuity and change in psychological variables (via correlations- T1 and T2) To date, results collected from studies that span up to 50 years What do longitudinal studies show? High DC in personality traits over the adult lifespan Study by Conley (1958a) - 50 yr. longitudinal study of hundreds of adults -All newlyweds at beginning of study - Ps rated themselves and were rated by spouse at 4 time points (1935, 1938, 1954, 1955, 1980, 1981) - Self ratings agreed with spouse ratings on many traits - Both self and spouse ratings showed high DC Self-ratings on given trait at T1 predicted spouse ratings of that trait at T2 DC in trait ratings displayed when examining: a) Self-ratings over time b) Spouse ratings over time c) Ability of one kind of rating to predict another kind of rating for same trait over time - There was good longitudinal consistency for E and N Study by Costa et al. (1980) - 460 male volunteers in Baltimore Longitudinal Study of Aging - Assessed different traits at two times: o At time of first testing, ps ranges in age from 17-85 o Correlations btw E scores at T1 and T2 separated by 6 to 12 yr period (above .70) so there was substantial DC o High stability coefficients for ratings of N Results from longitudinal studies also examine Big 5 traits Generally, DC shown all of Big 5 across intervals ranging 3-30 yrs PSYC 332­ Introduction to Personality  Scales Measuring The Big 5: 1. NEO-PI 2. 16 PF: Tense 3. ACL: Adaptability 4. Neuroticism 5. MMPI factors Most R coefficients are around .65 (very high) Test-Retest reliability .85 because doesn’t always give same score from one day to next Despite good evidence for DC in traits over time, traits scores are NOT perfectly stable Reasons for instability: error of the measures, change and fluctuation in traits Personality trait scores at T1 in adulthood are good but not perfect predictors of scores on those same traits at T2 Factors influencing strength of DC: - Length of time interval between testing: longer time interval Means lower DC - Some traits show higher DC regardless Study by Schuerger et al. 1989 - Reviewed 89 longitudinal studies of personality traits w/ main focus on N and E (anxiety) - Found that test-retest correlations on traits declined as time interval increased: around .7 for short time intervals (1 yr) and then gradually decreases as interval lengthens reaching .5 for very long intervals (over 10 yrs) - E shows higher DC than N (antiety) and continuity of overall average of other traits Another factor influencing differential continuity: age of the participants- belief that as people age, the change less and less relative to one another Roberts & DelVecchio (2000) - Stability coefficients were lowest in studies of children’s traits (.41) - Higher among young adults (.55) - Reached plateau for adults between ages: 50 and 70 (.7) - Suggests we should expect higher DC in personality traits as people age through midlife - As people move into adulthood and middle age, stability coefficients increase and distributions of trait scores show less internal fluctuation & more interindividual continuity - Results suggest that trait ratings in children show less DC than trait ratings in adulthood (kids develop more rapidly and fluidly) Researchers hesitant to study kids traits in the same way as adult traits But do adult traits develop from children’s traits? CHILDHOOD PRECURSORS: FROM TEMPERAMENT TO TRAITS Before the second child, parents think first born is product of the environments they provide- then they realize how different even infants can be from one another (inborn differences in personality) Temperament: differences in basic behavioral style, observed early in life and under significant and direct biological control Represent the ‘early in life framework’out of which personality traits eventually emerge Thomas, Chess, and Birch (1970): - Devised simplest and best known scheme for measuring different types of temperaments & understanding what they measure - Based on interview of mothers and babies - Distinguished among 3 different types of temperament patters PSYC 332­ Introduction to Personality  Thomas, Chess, & Birch’s Infant Temperaments Temperament Style Mood Emotional Eat & Sleep Other Characteristics Reactivity Cycles 1) Easy Consistently Low to moderate Regular positive intensity 2) Difficult Consistently High intensity Irregular negative 3) Slow-to-warm-up Relatively Low intensity - Combination of 1 & 2 negative - Tendency to withdraw from new events initially but approach them later More refined schemes for categorizing temperament: Rothbart (1986) - 6 Temperament Dimensions observed in First Yr of Life: 1) Activity Level 2) Smiling & laughter 3) Fearfulness 4) Distress to limitations 5) Soothability 6) Vocal activity Other Temperaments with Important Implications: Behavioral Inhibition Effortful control Jerome Kagan (1989) Behavioral Inhibition: extremely young children show timidity in face of new events and people - 15% of 2 yr old Caucasian children are inhibited: consistently shy & emotionally subdued in unfamiliar situations - 15% are uninhibited: sociable & affectionately spontaneous - Believes extremely shy & extremely sociable children constitute two separable genetic types whose behavioral differences are partly function of different thresholds of reactivity in limbic system Inhibited children Reluctant to play with unfamiliar toy In Kindergarden- shy away fro new activities & ppl Stage fright in new situations Intense physiological responses: more dilated pupils & higher HR when in mildly stressful social situations Higher levels of morning cortisol in the blood (heightened arousal)- same with rhesus monkeys in same position Lower threshold of reactivity More easily aroused in social situations & respond by withdrawing PSYC 332­ Introduction to Personality  Eysenck on Introversion: Similar to Kagan on Inhibition Introverts are overly aroused in general & withdrawal beh is effort to decrease arousal levels Recent research by Kagan (1994) found: behaviorally inhibited children more likely to show neural activation of right frontal lobe while uninhibited children more likely to show activation of left frontal lobe Right frontal activity: negative affectivity (fear & depression) Left frontal activity: positive affectivity (joy and happiness) Kagan believes that that link between inhibition & combination of introversion & neuroticism in adulthood will eventually be shown Kagan (1994) Out of every 100 Caucasian newborns: - 20% will show extreme irritability & excitability shortly after birth - By age 2: 75% of them will be: shy, timid, and fearful upon meeting unfamiliar people, put in unfamiliar rooms, or encounter unfamiliar objects - By adolescence: 10 will still be very shy - By adulthood: 6 or 7 of original 20 are introverted in their behavior (ones who lost shyness were probably influenced by environment encouraging them to be more outgoing) - BUT even the ones who lost the shyness but were originally inhibited children will keep ‘shyness physiology’ Effortful control: active & voluntary capacity to withhold dominant response in order to enact subordinate response given situational demands- ability to control one’s impulses. Kids with High Effortful Control - Keep themselves in check in situations where impulsive behavior could lead to trouble - Delay immediate gratification to focus attention on longer term goals and rewards - In preschool: better able to resist candy when told to or focus attention on a game even if want something at moment - In grade school: able to resist temptation if it will lead to later rewards. Ex. watching TV Research has shown: high levels of effortful control predict- Successful interpersonal functioning Better school grades Fewer behavioral problems Important factor in moral development & consolidation of conscience Paves way for rule compliance & ability to cooperate interact w/ others respectfully Stats on Effortful Control From early age, girls show more effortful control than boys Differences in social class also More economically deprived- lower EC Levels also improve over time: older children are better at controlling impulses (marked improvement between ages 2 and 4) Individual differences show good longitudinal consistency Study by Li-Grinning (2007) - 439 African American & Latino children between ages 2 & 4, and again 16 months later - Tested delay of gratification (component of EC) - Found overall correlation of .40 between first and second assessment suggesting moderate interindividual stability over 16 month period Not sure how stable individual differences are over longer period but suggestion is that indices of EC are related to later Conscientiousness Not many studies have tracked early temperament with later personality traits bc scales used in each are so different (mother reports of infant beh. vs. self-report) PSYC 332­ Introduction to Personality  Temperament dimensions measured by different taxonomies: Irritability, positive affect, activity level, rhythmicity, adaptability, sensory threshold, soothability, intensity of mood etc… Some researchers believe Big 5 taxonomy cud be used to classify children with variables related to temperament but others don’t feel match can be found Landmark study by Caspi et al (2003) - Part of the Dunedin study - 1000 ps born betweenApril 1972 & March 1973 - Tested at ages: 3, 5, 7, 9, 11, 13, 15, 21, 26 yrs - At age 3, each child in study participated in 90 minute developmental testing session & were rated on 22 behavioral characteristics - Ratings grouped to produce 5 different temperament types: Temperament Type Characteristics Well-adjusted -Appropriate levels of self control -Adequate self confidence - Did not become upset when confronting novel situations Undercontrolled - Mostly boys - Impulsive, restless, negativistic, distractible - Showed strong & volatile emotional reactions Confident -Adjusted quickly to testing situation - Showed characteristics of friendliness, impulsivity, & enthusiasm Inhibited - Mostly girls - Socially reticent (reserved), fearful, easily upset by examiner Reserved - Timid/ uncomfortable in testing session - But less shy and cautious than inhibited children Order: most to least prevalent (in this study) Well-adjusted Confident Reserved Undercontrolled Inhibited At age 26: trait ratings collected via self-report & friends/acquaint. There was continuity on certain dimensions Most predictable children were: undercontrolled & inhibited types Some Correlates of the Personality Types Personality Type Correlates/ Outcomes Undercontrolled Scored highest on trait measures of negative emotionality Easily upset-likely to overact to minor events Feel mistreated, deceived, and betrayed by others Described by others as: antagonistic, unreliable, tense, narrow-minded Predicts high levels of N and low levels ofAand C in adulthood PSYC 332­ Introduction to Personality  Inhibited Overcontrolled & non-assertive personality style High constraint Low positive emotionality Predicts low levels of E The three other personality types did not show clear-cut profiles in adulthood but continuity still observed Ex. confident children became extraverted adults, reserved children were lower in E and O Temperament according to Caspi (1998): psychobiological core around which personality is structured Developmental elaboration: process through which temperament dimensions gradually develop into more fully articulated personality trait Complex interplay through which inborn tendencies both shape and are shaped by environment over time There are 6 mechanisms of developmental elaboration The 6 Mechanisms of Developmental Elaboration (How temperament dimensions develop into personality traits) Mechanism Description Learning processes Temperamental differences determine what kids learn, and how they earn it Environmental elicitation Temperamental differences elicit different reactions from the environment which may reinforce initial differences Environmental construal Temperamental differences influence how kids process information about their environment- shaping experiences of their environment Social and temporal comparisons Temperamental differences influence how kids compare themselves to themselves (over time) and to others- shaping their developing self-concepts Environmental selection Temperamental differences influence how kids choose environments intern influencing development of personality traits (might chose environment consistent w/ temperament which reinforces already present dispositions) Environmental manipulation Once self-concepts are established, kids will manipulate their environments to confirm or elaborate dispositions they already have Physical and social environments kids chose feedback to influence their further development According to Caspi: initial dispositions from infancy gain strength and become more elaborated over time until they become full-fledged personality traits Results from the Dunedin study showed: certain predictable trajectories can be documented but results show unpredictability and discontinuity over time PSYC 332­ Introduction to Personality  Inborn temperamental tendencies give rough template for development of adult traits but template is flexible and subject to changes from environment THE ORIGINS OFTRAITS: GENES & ENVIRONMENTS It is known that MZ twins have more in common than DZ twins Identical (MZ) twins share tastes, characteristics and interests, while DZ twins are no more alike than regular siblings MZ twins have same genetic makeup, DZ twins only share ½ their genes 1980s study about Twins reared apart: years later, still showed many similarities and concordances in tastes and behaviors Examples: 2 fire chiefs, 2 romantic husbands, 2 fashion designers, 2 car experts… THE LOGIC OFTWINANDADOPTION STUDIES You can’t have anything without BOTH genes AND environment Our traits are a product of the interaction of genes and environment In US- said that 90% of variability in height is genetic 10% associated w/ environmental factors (nutrition & social class) Tall people have tall kids Two important implications of scientific findings on height: 1) The 90% genetic variance refers to ‘the group’not particular person 2) The percentages of variability (90%-10%) depend on characteristics of the population a. Malnutrition can impact height b. Anation’s average height is good indicator of their wealth and levels of physical health In dire situations, like famine (thought they are rare) percent distribution of variability is likely different (ex. less than 90% due to genetics- more than 10% due to environment The Heritability Quotient: estimates the proportion of variability in a given characteristic that can be attributed to genetic differences between people (one of most difficult and misunderstood problems in psychology) – ex. HQ for height is 90% Biochemical components of the genetic code: thymine, adenine, cystosine, guanine With regard to personality: - Remember that genetic influences on traits are indirect and complex (there is no single gene that matches cleanly to a personality trait) - Remember that there is much genetic similarity across human species in general (90% of genes are identical from one individual to another are identical) o In discussing heritability-talking about 10% that is variable Two main methods used by behavioral scientists to make heritability estimates: Natural studies 1) Twin studies a. MZ and DZ samples b. Measure traits and determine correlations and their magnitude for both types of twin pairs c. Formula for estimating heritability in twins: h² = 2(Rmz – Rdz) Heritability Quotient = 2 x correlation (MZ) – correlation (DZ) 2) Adoption studies a. Examine extent to which adoptive children share similar traits with members of adoptive families b. Compare them to biological siblings (share 50% of genetic makeup) vs 0% in adoptive siblings c. Evidence for heritability can be claimed when correlations of biological siblings are greater than for adoptive siblings d. Helps nature vs. nurture in unique way: correlations between adopted kids and their biological parents would be 100% genetic bc they don’t share environment and PSYC 332­ Introduction to Personality  correlations between adopted kids and their adoptive parents would be 100% environmentat bc they don’t share any genes Behavior genetics: scientific discipline with roots in psychology, genetics, biology, and related fields- that explores empirical evidence concerning relative influences of genetic and environmental factors in accounting for variability in human behavior Twin and adoption studies form basis for many of field’s findings about heritability of personality traits HERITABILITY ESTIMATES OFTRAITS Research shows- virtually all traits that can be reliably measured are at least moderately heritable Big Swedish study (Floderus-Myrhed et al. 1980) found heritability estimates of slightly over 50% for E and N traits University of Minnesoda study: greater than 40% heritability for traits of: Leadership, mastery, traditionalism (following rules and respecting authority), stress reaction, absorption (engrossed in sensory experiences), alienation, well-being, avoidance of harm, aggressiveness Authoritative review of Behavioral Genetic Studies in Personality (Plomin et al, 1990): Important findings - On average MZ correlations are .50, DZ are .30 - Twin correlations suggest that genetic influence on personality is significant AND substantial - Proportion of phenotypic variance explained by genetic variance is 40% These results have been supported by studies in 90s In terms of The Big 5: - For N, E, and O- MZ correlations are more than twice as large as DZ correlations - Heritability for the Big 5 are in 40-50% range - Strongest heritability in study for Study by Loehlin et al. (1998) - MZ and DZ high school students - Found heritability estimates on Big 5 of 51% to 58% - Concluded that Big 5 are substantially and equally heritable - Sub-traits of Big 5 also show heritability (Jang et al. 1998) So twin studies consistently suggest that personality traits are at least moderately heritable- sometimes substantially Heritability estimates normally in 40-50% range Puzzling findings: 1) Some studies show MZ correlations that are twice as high as DZ (N, E, O) Logic: because MZ share twice as much DNAas DZ, they shouldn’t be more than twice as similar to each other (genetic variance should be additive) 2) Adoption studies show lower heritability estimates (biological siblings are no more alike than are adoptive siblings- heritability estimates around 20%) Our relative standing on traits is only mildly similar to that of our biological siblings MZ twins are more alike than DZ twins and regular biological siblings Nonadditive genetic variance: genes may not influene traits in a linear, additive way- instead interact in configural pattern where all components are essential and absence or change in one can produce large qualitative or quantitative change in the result Dunn and Plomin’s Question (1990): Why are siblings so different? 50% shared genes isn’t much more than 0%- unless share 100% of genes, not likely to be that similar on traits Emergenesis: emergent property of configuration of genes or basic traits that are genetic in origin- certain patterns of genes may give rise to particular behavioral tendencies that would not themselves be produced even in attenuated form, by the pieces that make up the pattern SHARED ENVIRONMENT PSYC 332­ Introduction to Personality  Since heritability percentage known to be 40-50% - 50% of variance in personality traits can be explained by environmental effects Childrearing styles, family patterns, schools neighborhood… But it isn’t that simple University of Minnesota study (Tellegen et al. 1988): examined twins reared together and apart Table 6.2: Correlations for MZ Twins reared apart & together Pg. 225 – Things to note 1) Correlations for MZ twins reared together on social potency & stress reaction are in line with what we’d expect from similar traits 2) Correlations for MZ twins reared together are almost identical to MZ twins reared apart - so shared environment doesn’t seem to make MZ twins reared together any more similar that MZ twins reared apart Exception: with social closeness correlations for reared together were higher than reared apart their adoptive mothers (0) Exceptions to the rule: Traits showing family env. effect
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