PSY100 Personality

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• PSY100 Personality
• Approaches to the Scientific Study of
  Personality
• Describing and Measuring Individual Differences
• Validating Individual Difference Measures
• Important Consequences of Individual Differences
• Causes of Individual Differences

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• How does Personality Psychology differ from Other
  Disciplines in Psychology?
• Cognitive psychology The science of basic
  cognitive processes
• Neuropsychology The science of the connection
  between the brain and the mind
• Social psychology The science of social
  influences on psychological processes
• Developmental psychology The science of changes
  in psychological processes over the life span.

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• All these disciplines implicitly assume that all
  people are the same.
• Personality psychology makes a different
  assumption People are different from one another
  in important ways.
• Cognitive Why do some people have better
  memories than others?
• Social Why do people respond differently to
  rejection by others?
• Developmental Why are some children more afraid
  of strangers than others?

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Two Approaches to Personality Idiographic versus
Nomothetic Approach The idiographic
(person-centered) approach A focus on one
individual at a time, and it tries to understand
this individuals actions from the individuals
characteristics. The nomothetic
(variable-centered) approach A focus on the
relation between a certain outcome such as
academic achievement (getting an A in this class)
to a variable like organized-disorganized.
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Idiographic Nomothetic Traditional ModernGra
nd Theories Small TheoriesOne individual at a
time Large samplesQualitative QuantitativeFreu
d Eysenck Idiographic question Why did
Mariah Carey have a nervous breakdown? Nomothetic
question Are young stars in the music industry
more likely to suffer a nervous breakdown than
normal people?
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• Freud Rogers It is impossible to test
  scientific theories with case studies.
• Skinner Behaviorism assumed that all people
  are born equal and that individual differences
  are a mere consequence of different learning
  experiences. Nobody believes this anymore.
• Eysenck An influential early proponent of the
  nomothetic approach. Although unnecessarily
  confrontational, his work continues to influence
  modern personality research.

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• Important Notice
• As noted in the textbook, in recent decades the
  study of personality has shifted toward narrower
  research programs that examine specific aspects
  of personality
• In other words, most contemporary personality
  research takes the nomothetic approach.
• Consistent with this modern trend, my second
  year course PSY230 Introduction to
  Personality focuses exclusively on the modern,
  nomothetic approach to personality psychology.

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Warning If you want to learn more about
psychodynamic theories (Freud, Adler, Jung), DO
NOT take PSY230 However, I hope to convince you
in the rest of todays lecture that the
nomothetic approach examines interesting
questions and provides answers that are relevant
to the understanding of yourself and others.
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• The Scientific (Nomothetic) Study of Personality
  and Individual Differences
• Three Goals of Personality Psychology
• Classification How do people differ?
• Causes Why do individuals differ from each
  other?
• Consequences What are the effects of individual
  differences?

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• Examples
• How consistent are people in their behaviors?
  When somebody is friendly to us, how likely is it
  that this person is also friendly to others.
• Why are some people friendlier than others?
  Nature vs. nurture How much is personality due
  to genetic differences? How much influence do
  parents have on their childrens personality?
• What are the consequences of personality?Does
  personality predict important life-outcomes such
  as longevity, happiness, and income?

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• The Scientific Study of Individual Differences
• The nomothetic approach to personality research
  relies heavily on correlations (textbook pp.
  54-56).
• Correlations provide information about the
  relation between variability in two variables.

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• Examples
• Stability Will individual differences in todays
  friendliness be the same in the future?
• Consistency Are individual differences in
  friendliness in one situation the same in a
  different situation?
• Cause Do genetic differences predict individual
  differences in friendliness?
• Consequences Do individual differences in
  friendliness predict individual differences in
  happiness?

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r .73 r2 50
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• Describing Individual Differences
• Everyday language provides thousands of words to
  describe individuals (honest, caring, ambitious,
  orderly, shy, modest, self-confident,)
• Correlations (and more advanced statistics) show
  that individual differences in some of these
  traits (characteristics) are related (e..g, shy
  is negatively related to confident).
• As a result, it is possible to describe
  personality with fewer dimensions.

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• The Big Five
• Initially, personality psychologists used
  different traits to describe personality and
  there exist hundreds of measures to measure
  individual differences in these traits.
• In the past two decades, it was discovered that
  these measures are related to each other and can
  be reduced to five major traits that
  differentiate one individual from another.
• The Big Five provide a comprehensive first
  impression of an individual. They do not capture
  all aspects of individual differences.

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• The Atlas Analogy
• I like to compare the Big Five to continents.
• Continents capture important differences between
  regions of the word (Europe is different from
  Asia).
• However, there still exists important
  differences between countries in each continent
  (Germany is different from Italy).

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• The Big Five
• Neuroticism A disposition to experience more
  negative feelings and low self-esteem.
• Extraversion A disposition to be outgoing,
  risk-taking, and cheerful.
• Openness A disposition to be curious and
  interested in novel and unconventional things.
• Agreeableness A disposition to be caring and
  modest
• Conscientiousness A disposition to be
  organized, ambitious, and dependable.

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• Measuring Personality Traits
• Self-report The easiest and most widely used
  method (e.g., I am self-confident). Assumes
  that people are honest and know themselves.
• Informant reports asking acquaintances (e.g.,
  Joe is self-confident) more difficult to obtain
  assumes that others know the person well.
• Observing behavior e.g., research assistants
  rate personality based on videotapes of behavior
  time-consuming

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• Experience sampling ask participants to keep a
  diary or momentary records of their thoughts,
  feelings, and behaviors. Time-consuming, requires
  high motivation and honesty of participants.
• Each methods has its advantages and drawbacks.
• The best way of measuring personality would be
  to use multiple methods. For example, we are
  currently conducting a study of married couples
  in which we assess personality with self-reports,
  informant reports, and experience sampling.

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I tend to be relaxed and handle stress well. I
tend to worry a lot.I tend to be quiet. I tend
to be outgoing and sociable.I tend to be
original and come up with ideas. I tend to like
to reflect and to play with ideas. I tend to be
considerate and kind to almost everyone.
I tend to be rude to others. I tend to do a
thorough job. I tend to do things efficiently.
1 2 3 4 5 6 7Strongly disagree strongly agree
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Scoring of Your Personality Test N 12
8.60 3.00 E 34 9.01 3.00 O 56
9.73 2.35 A 78 11.39 2.00 C 910 10.53 2.09

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• Stability of Personality
• Relative differences in personality are quite
  stable over time.
• Stability increases over the life-span. It is
  not fixed at 20.
• Personality changes with age - Neuroticism,
  Extraversion, Openness decrease.- Agreeableness,
  Conscientiousness increase.

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• Consequences of Personality
• Personality and Health
• Personality and Longevity
• Personality and Happiness
• Personality and Marital Satisfaction (Divorce)
• Personality and Job Performance (Income)

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• Personality and Health
• Stress is related to illness Suppression of
  the immune system.
• Neuroticism is related to stress-reactivity.
• We would expect neuroticism to be related to
  health.
• However, neuroticism is more related to
  subjective perception of symptoms (hypochondria)
  than to objective health.

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• Personality and Longevity
• It is difficult to study the relation between
  personality and longevity.
• The Terman-study assessed personality of gifted
  children in the 1920s and 1930s. Now researchers
  can examine which children are still alive.
• Conscientiousness is the best predictor of
  longevity.
• The processes underlying this relationship are
  still unclear.

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• Personality and Happiness
• Extraversion is a disposition to experience more
  positive affect (pleasant feelings).
• Neuroticism is a disposition to experience more
  negative affect (unpleasant feelings).
• Extraversion and Neuroticism are the most
  important personality predictors of
  life-satisfaction.

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• Personality and Marital Satisfaction
• Research on personality and marital satisfaction
  has a long history (since 1930s).
• Most studies show a negative effect of
  neuroticism on marital satisfaction and a
  positive effect on divorce.
• Another interesting finding is that people do
  not marry on the basis of personality Spouses
  personality scores are uncorrelated.

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• Personality and Job Performance
• It is plausible that some personality traits
  help people in certain jobs - extraversion
  service jobs - optimism sales jobs
• In addition, conscientiousness is a good
  predictor of job performance in many different
  jobs (work ethic)
• Conscientiousness becomes a stronger predictor
  of job performance with higher autonomy.

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• Causes of Personality
• The relative contribution of genetic/biological
  factors versus environmental/cultural factors has
  been a major controversy.
• After the first child parents believe in
  environmental factors.
• After the second child parents believe in
  genetic factors.
• What is the evidence?

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• Twin Studies
• Before DNA testing (before the 1990s),
  researchers had to rely on indirect evidence to
  examine the influence of nature (genes) and
  nurture (environment).
• Twin studies capitalized on the difference
  between monozygotic twins (MZ) and dizygotic
  twins (DZ).
• MZ twins are genetically identical.
• DZ twins share on average 50 of their genes,
  just as much as other siblings.

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• Genetic Contribution to Personality
• To examine a genetic contribution, we can
  compare the similarity of MZ twins to the
  similarity of DZ twins.
• (Given certain assumptions), if MZ twins are
  more similar to each other than DZ twins, then
  genes must influence the trait.
• For example, the height of MZ twins correlates
  very highly (r .90), whereas the height of DZ
  twins is correlated less highly (r .45).
• Height is genetically determined.

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• Numerous studies have demonstrated greater
  similarity (higher correlations) for MZ twins
  than for DZ twins for personality traits
  including the Big Five.
• Today nobody doubts that genetic factors
  contribute to personality.
• Twin studies also lead to the conclusion that
  growing up in the same household has no influence
  on personality.
• This finding is the topic of a heated debate as
  it is hard to believe that parents have no
  influence on the personality of their children.

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• Do Genes Determine Personality?
• Genes cannot directly influence experiences and
  behavior.
• Genes influence biological processes, which in
  turn influence experiences and behavior.
• Understanding these processes can help people to
  change their personality.

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• Neuroticism has been linked to a gene that
  influences the reuptake of serotonin in the
  brain.
• Drugs like Prozac (SSRIs) change the biological
  reuptake mechanism.
• Studies show that drugs like Prozac change
  personality scores on a Neuroticism scale.
• SSRIs also have several side-effects. They are
  used only when people suffer from abnormal levels
  of depression and anxiety.
• What should we do when it becomes possible to
  change personality at will?

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• Cultural influences on personality
• Cross-cultural studies show variation in
  personality traits across cultures. For example,
  HK Chinese score lower on Extraversion and
  Openness.
• Acculturation studies show that personality
  changes. HK Chinese who migrated to Canada have
  higher extraversion and openness scores.
• In North America, Extraversion and Neuroticism
  scores have increased over the past decades.

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• Conclusion
• Personality psychology examines individual
  differences.
• It relies more on correlations than on
  experimental studies.
• It examines the major traits that differentiate
  people.
• It examines the consequences of individual
  differences for real-world outcomes.
• It examines the causes of individual differences.