Chapter 2 Personality Research Methods

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Chapter 2Personality Research Methods
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Measuring personality variables

• What is a variable?
• What kinds of variables are there?
• Categorical variables (examples gender,
  political affiliation)
• Continuous variables (height, weight)
• How can we measure an aspect of personality as a
  variable?
• Psychometrics (psyche mind, metric measure)
  an applied branch of psychology that deals with
  psycho-logical measurement
• The most commonly used approach the self-report
  questionnaire measure

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Personality InventoryPlease read the following
items and decide how well they describe your
personality. Respond to each according to the
following list of alternatives

• a. very much
  unlike me
• b. somewhat unlike
  me
• c. somewhat like me
• d. very much like
  me
• I am socially somewhat awkward.
• I dont find it hard to talk with strangers
• I feel tense when Im with people I dont know
  well.
• When conversing I worry about saying something
  dumb.
• I feel nervous when speaking to someone in
  authority.
• I am often uncomfortable at parties and other
  social functions.
• I feel inhibited in social situations.
• I have trouble looking someone right in the eye.
• I am more shy with members of the opposite sex.

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Measuring personality variables

• What is a variable?
• What kinds of variables are there?
• Categorical variables (examples gender,
  political affiliation)
• Continuous variables (height, weight)
• How can we measure an aspect of personality as a
  variable?
• Psychometrics (psyche mind, metric measure)
  an applied branch of psychology that deals with
  psycho-logical measurement
• The most commonly used approach the self-report
  questionnaire measure

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NAME HEIGHT (X) WEIGHT (Y)
Allport, Allen 69 175
Bimiup, Scotty 68 159
Brewer, Joseph 71 177
Derrickson, Derek 68 150
Dorman, Carlton 67 162
Horne, Karyn 65 134
Ingram, Irene 64 121
James, Jocelyn 67 125
Jones, Ernie 67 158
Lang, Fred 69 161
Kelly, Christine 63 119
Lime, Nora 68 128
etc.
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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Personality InventoryPlease read the following
items and decide how well they describe your
personality. Respond to each according to the
following list of alternatives

• a. very much
  unlike me
• b. somewhat unlike
  me
• c. somewhat like me
• d. very much like
  me
• I am socially somewhat awkward.
• I dont find it hard to talk with strangers
• I feel tense when Im with people I dont know
  well.
• When conversing I worry about saying something
  dumb.
• I feel nervous when speaking to someone in
  authority.
• I am often uncomfortable at parties and other
  social functions.
• I feel inhibited in social situations.
• I have trouble looking someone right in the eye.
• I am more shy with members of the opposite sex.

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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Item-to-total correlations
SHY1 SHY2 SHY3 SHY4 SHY5 SHY6 SHY7 SHY8 SHY9
SHY .68 .64 .67 .67 .65 .73 .75 .57 .61
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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Reliability (internal consistency) Cronbachs
alpha .83 Factor pattern
Factor 1
SHY1 .69
SHY2 .62
SHY3 .67
SHY4 .66
SHY5 .65
SHY6 .75
SHY7 .78
SHY8 .54
SHY9 .58
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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

25

Personality InventoryPlease read the following
items and decide how well they describe your
personality. Respond to each according to the
following list of alternatives

• a. very much
  unlike me
• b. somewhat unlike
  me
• c. somewhat like me
• d. very much like
  me
• I am socially somewhat awkward.
• I dont find it hard to talk with strangers
• I feel tense when Im with people I dont know
  well.
• When conversing I worry about saying something
  dumb.
• I feel nervous when speaking to someone in
  authority.
• I am often uncomfortable at parties and other
  social functions.
• I feel inhibited in social situations.
• I have trouble looking someone right in the eye.
• I am more shy with members of the opposite sex.

26
Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Example of concurrent validity

• Correlate the participants total shyness
  score for the 9-item measure of shyness (X
  variable) with their rating on the following
  dimensional scale (Y variable)
• In general, how shy are you?
• ______________________________________________
  ___________
• 0 10 20 30 40
  50 60 70 80 90 100
• If both X and Y are good alternative ways to
  measure shyness, the correlation between X and Y
  should be positive and large (for example, r
  .88).

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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Example of convergent and discriminant validity

• Correlate the participants total shyness
  score for the 9-item measure of shyness (X
  variable) with their total scores on the
  following other personality measures
• 
  Shyness score correlated with
• Social anxiety
  .91
• Introversion
  .82
• Conscientiousness
  .15
• IQ
  .03
• The first two correlations provide evidence
  of the shyness measures convergent validity.
• The last two correlations provide evidence
  of the shyness measures discriminant
• validity.

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Reliability and validity in personality
measurement

• Reliability (consistency of measurement)
• Internal consistency
• Item-to-total correlation
• Corrected item-to-total correlation
• Split-half reliability
• Cronbachs alpha
• Test-retest reliability
• Validity (construct validity)
• Face validity
• Concurrent validity
• Convergent and discriminant validity
• Criterion (predictive) validity

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Four possible causal structures of an A-B
relationship

• A B Changes in Variable A cause
  corresponding changes to occur
• in Variable B
• B A Changes in Variable B
  cause corresponding changes to occur
• in Variable A
• A B Changes in Variable A cause changes in
  Variable B, which
• in turn cause
  changes in Variable A, which in turn . . .
• A Changes in Variable C cause
  corresponding changes in both
• C Variables A and
  B. Variables A and B therefore covary even
• B though neither one causes the other

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Three categories of moderating variables in
personality research
Category Function Representative Example
Situational moderating variables Specify in which types of situations traits will be good versus poor predictors of their trait-relevant behaviors Psychologically weak versus strong situations
Personal moderating variables Specify for which types of people traits will be good versus poor predictors of their trait-relevant behaviors Private self-consciousness
Criterion moderating variables Specify the types of behaviors that traits will predict either well or poorly Level of aggregation of the behavioral measure
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Experimental study Correlational study
Goal Test for a causal relationship between a manipulated variable and a measured variable Test for a correlational relationship between two measured variables
Variables Independent variable (manipulated) Dependent variable (measured) Predictor variable (measured) Criterion variable (measured)
Criteria Experimenter controls the IV Random assignment to conditions Measures of both the predictor and the criterion variables must be obtained
Major pitfalls Confounded manipulation of the independent variable Confounded measurement of the dependent variable Using a measured variable that is unreliable or that lacks validity Confounded measurement of the predictor variable Confounded measurement of the criterion variable Using measured variables that are unreliable or that lack validity
Possible conclusions Level of IV affects level of DV Level of IV doesnt affect level of DV PV is related to (associated with) CV PV is not related to CV
Best safeguard Replication Replication
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Methods for measuring aspects of personality

• Trait inventories (e.g., self-report
  questionnaires)
• State experience measures (e.g., mood ratings)
• Ability tests (e.g., intelligence test)
• Subjective ratings (e.g., self-ratings of
  behavior)
• Objective ratings (e.g., observer ratings of
  behavior)
• Behavioral measures (e.g., counts of specific
  behaviors)
• Physiological measures (e.g., galvanic skin
  response)

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Personality InventoryPlease read the following
items and decide how well they describe your
personality. Respond to each according to the
following list of alternatives

• a. very much
  unlike me
• b. somewhat unlike
  me
• c. somewhat like me
• d. very much like
  me
• I am socially somewhat awkward.
• I dont find it hard to talk with strangers
• I feel tense when Im with people I dont know
  well.
• When conversing I worry about saying something
  dumb.
• I feel nervous when speaking to someone in
  authority.
• I am often uncomfortable at parties and other
  social functions.
• I feel inhibited in social situations.
• I have trouble looking someone right in the eye.
• I am more shy with members of the opposite sex.

38
Methods for measuring aspects of personality

• Trait inventories (e.g., self-report
  questionnaires)
• State experience measures (e.g., mood ratings)
• Ability tests (e.g., intelligence test)
• Subjective ratings (e.g., self-ratings of
  behavior)
• Objective ratings (e.g., observer ratings of
  behavior)
• Behavioral measures (e.g., counts of specific
  behaviors)
• Physiological measures (e.g., galvanic skin
  response)

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Example of a Mood Adjective Check List

• Check all of the following adjectives that
  describe your current mood
• ____ anxious ____ nervous
• ____ agitated ____ relaxed
• ____ serene
• ____ apprehensive
• ____ calm
• ____ confident
• ____ confused

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Methods for measuring aspects of personality

• Trait inventories (e.g., self-report
  questionnaires)
• State experience measures (e.g., mood ratings)
• Ability tests (e.g., intelligence test)
• Subjective ratings (e.g., self-ratings of
  behavior)
• Objective ratings (e.g., observer ratings of
  behavior)
• Behavioral measures (e.g., counts of specific
  behaviors)
• Physiological measures (e.g., galvanic skin
  response)

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IQ tests are cognitive ability tests
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Methods for measuring aspects of personality

• Trait inventories (e.g., self-report
  questionnaires)
• State experience measures (e.g., mood ratings)
• Ability tests (e.g., intelligence test)
• Subjective ratings (e.g., self-ratings of
  behavior)
• Objective ratings (e.g., observer ratings of
  behavior)
• Behavioral measures (e.g., counts of specific
  behaviors)
• Physiological measures (e.g., galvanic skin
  response)

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Observing and recording behavioral measures
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Methods for measuring aspects of personality

• Trait inventories (e.g., self-report
  questionnaires)
• State experience measures (e.g., mood ratings)
• Ability tests (e.g., intelligence test)
• Subjective ratings (e.g., self-ratings of
  behavior)
• Objective ratings (e.g., observer ratings of
  behavior)
• Behavioral measures (e.g., counts of specific
  behaviors)
• Physiological measures (e.g., galvanic skin
  response)

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A penile plethysmograph
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