PSY230H5 Lecture Notes - Lecture 5: Meta-Analysis, Longitudinal Study, Personality Psychology

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17 Oct 2018
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Department
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Stability of personality
Scientific relevance: fundamental assumption of personality psychology:
personality traits are stable
Personal relevance: will you still be the same in 10 years? How likely is ti that
people you care about will be the same, change, improve?
Stability of individual differences
Assessed with retest correlations
Retest interval: the time interval between 2 assessments of personality (one
month, one year)
Stability: retest correlations over longer time periods (years)
True stability: retest correlations over longer time periods adjusted for
unreliability
Stability of personality: meta analysis
Meta-Analysis: A meta-analysis combines results of several original studies.
Original Studies:
Method. Assessed personality traits repeatedly over longer time intervals
(at least one year apart)
Data in the meta-analysis: 3,217 correlation coefficients from 152 longitudinal
studies of personality.
People become more stable in their personalities
Why are retest correlations not r=1.00?
Measurement Error. Reduces correlations even if personality has not changed.
Variability. Temporary changes due to transient situational influences (e.g., bad
hair day).
Change. Long-term changes in personality traits.
Stability and change of the big five: self-perception versus actual personality
Requires a multi-method approach (self-ratings & informant ratings)
135 participants and their spouses rated personality twice (6 year retest interval).
A highly reliable Big Five measure.
Conclusion
Personality traits (Big Five) are very stable over long periods of time.
Other personality characteristics (attractiveness, intelligence, political orientation) are
also very stable over time.
Some characteristics are less stable over time
(life satisfaction, income).
Relevance: Your personality may be stable, but your happiness is not.
Age differences in big five personality traits: cross-sectional studies
Neuroticism, Extraversion and Openness decrease with age
Conscientiousness and Agreeableness increase with age
Limitation: cross-sectional studies confound cohort effects (born 1920, 1950, 1980)
and age effects (20, 40, 60 years after birth).
A longitudinal study of mean level change
Participants.
- 212 participants who were children in the 1920s.
- 248 infants born in Berkeley, CA, in the 1920s.
Method. Completed the California Personality Inventory (CPI) several times during
adulthood.
A meta analysis of longitudinal studies
Data. Obtained information about mean levels of personality from 92 longitudinal
studies.
Method. Computed standardized mean differences (Cohen’s d) between different age
groups.
Conclusion
Replicates increase in agreeableness and conscientiousness (effect of aging)
Does not replicate decrease in openness (cohort effect?)
Effect size is large over a life-time (10 cm growth from age 10 to age 80), but relatively
small over short time periods (4 cm from age 20 to age 30).
Specht et al. (2011) examined this question using the German SOEP data (N = 14,000)
Difficult to study due to high stability.
Difficult to study due to measurement problems.
If behavior changes, does it mean personality changes?
Few consistent results.
Main conclusion: Stability is more likely and change is unpredictable.
Personal relevance
Many of the characteristics that define your personality are likely to remain fairly
stable for the rest of your life. [This also applies to others]
Traits are not the same as actual behavior. You can use situational influences on
behavior (choice of friends, romantic partner, job, place to life, etc.) to influence your
life.
Life-outcomes (life-satisfaction, income) are less stable than your personality.
Week 5: Stability
Wednesday, October 17, 2018
1:49 PM
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Stability of personality
Scientific relevance: fundamental assumption of personality psychology:
personality traits are stable
Personal relevance: will you still be the same in 10 years? How likely is ti that
people you care about will be the same, change, improve?
Stability of individual differences
Assessed with retest correlations
Retest interval: the time interval between 2 assessments of personality (one
month, one year)
Stability: retest correlations over longer time periods (years)
True stability: retest correlations over longer time periods adjusted for
unreliability
Stability of personality: meta analysis
Meta-Analysis: A meta-analysis combines results of several original studies.
Original Studies:
Method. Assessed personality traits repeatedly over longer time intervals
(at least one year apart)
Data in the meta-analysis: 3,217 correlation coefficients from 152 longitudinal
studies of personality.
People become more stable in their personalities
Why are retest correlations not r=1.00?
Measurement Error. Reduces correlations even if personality has not changed.
Variability. Temporary changes due to transient situational influences (e.g., bad
hair day).
Change. Long-term changes in personality traits.
Stability and change of the big five: self-perception versus actual personality
Requires a multi-method approach (self-ratings & informant ratings)
135 participants and their spouses rated personality twice (6 year retest interval).
A highly reliable Big Five measure.
Conclusion
Personality traits (Big Five) are very stable over long periods of time.
Other personality characteristics (attractiveness, intelligence, political orientation) are
also very stable over time.
Some characteristics are less stable over time
(life satisfaction, income).
Relevance: Your personality may be stable, but your happiness is not.
Age differences in big five personality traits: cross-sectional studies
Neuroticism, Extraversion and Openness decrease with age
Conscientiousness and Agreeableness increase with age
Limitation: cross-sectional studies confound cohort effects (born 1920, 1950, 1980)
and age effects (20, 40, 60 years after birth).
A longitudinal study of mean level change
Participants.
- 212 participants who were children in the 1920s.
- 248 infants born in Berkeley, CA, in the 1920s.
Method. Completed the California Personality Inventory (CPI) several times during
adulthood.
A meta analysis of longitudinal studies
Data. Obtained information about mean levels of personality from 92 longitudinal
studies.
Method. Computed standardized mean differences (Cohen’s d) between different age
groups.
Conclusion
Replicates increase in agreeableness and conscientiousness (effect of aging)
Does not replicate decrease in openness (cohort effect?)
Effect size is large over a life-time (10 cm growth from age 10 to age 80), but relatively
small over short time periods (4 cm from age 20 to age 30).
Specht et al. (2011) examined this question using the German SOEP data (N = 14,000)
Difficult to study due to high stability.
Difficult to study due to measurement problems.
If behavior changes, does it mean personality changes?
Few consistent results.
Main conclusion: Stability is more likely and change is unpredictable.
Personal relevance
Many of the characteristics that define your personality are likely to remain fairly
stable for the rest of your life. [This also applies to others]
Traits are not the same as actual behavior. You can use situational influences on
behavior (choice of friends, romantic partner, job, place to life, etc.) to influence your
life.
Life-outcomes (life-satisfaction, income) are less stable than your personality.
Week 5: Stability
Wednesday, October 17, 2018 1:49 PM
Unlock document

This preview shows pages 1-2 of the document.
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