Personality and Individual DIfferences Test 1

Chapters 1 and 2 from 4th edition textbook by ashton

Psychological measurement

Measuring individual differences in psychological characteristics using scores that allow meaningful comparisons between people.

Interval scale

A scale in which equal score differences represent roughly equal differences in the trait; most psychological measures are treated this way.

True zero

A meaningful point of zero absence of a characteristic; psychological traits usually do not have one.

Why ratios usually do not apply to psychological traits

Without a true zero, it does not make sense to say one person has twice as much of a trait as another.

Rank order

A way of ordering people from highest to lowest on a trait; it does not show whether score gaps between ranks are equal.

Mean

The average score in a group.

Standard deviation (SD)

A number describing how spread out scores are around the mean.

Variance

The square of the standard deviation.

Standard score (z

score)

z

score formula

Properties of z

scores

T

score

Correlation coefficient (r)

A statistic showing the direction and strength of the relationship between two variables.

Range of r

Correlations range from

Positive correlation

Higher scores on one variable tend to go with higher scores on the other.

Negative correlation

Higher scores on one variable tend to go with lower scores on the other.

Zero correlation

No systematic relationship exists between two variables.

Interpreting r

A 1

Small correlation

Roughly between

Moderate correlation

Roughly between .20 and .40, or between

Large correlation

Greater than about .40 in absolute value.

Correlation does not equal certainty

A correlation predicts average tendencies in groups, not exactly what any individual person will do.

Reliability

The extent to which a measurement agrees with other measurements of the same characteristic; it indicates consistency and low random error.

Measurement error

Random influences that make a score imperfect rather than a pure measure of the intended characteristic.

Internal

consistency reliability

Why more items improve reliability

Averaging across more related items cancels out item

Item correlation

The degree to which responses to one item are related to responses to another item measuring the same trait.

Cronbach's alpha

The most commonly used estimate of internal

Split

half reliability

Parallel

forms reliability

Interrater reliability

The degree to which interchangeable observers or raters agree when judging the same people or behavior.

Test

retest reliability

Validity

The extent to which a measure actually assesses the characteristic it is intended to assess.

Reliability versus validity

Reliability means a measure is consistent; validity means it measures the right thing. A measure cannot be valid without being reasonably reliable.

Content validity

The extent to which a test's items adequately represent all important parts of the construct being measured.

Construct validity

Evidence that a measure truly assesses the theoretical characteristic it claims to measure.

Convergent validity

A measure should correlate strongly with other measures of the same or a closely related construct.

Discriminant validity

A measure should correlate weakly with measures of unrelated constructs.

Criterion validity

The extent to which a measure predicts an important external outcome or criterion.

Predictive validity

Criterion validity specifically involving prediction of future outcomes.

Criterion

A practically important outcome variable, such as job performance, grades, treatment response, or criminal behavior.

Self

report

Self

rating

Observer report

A personality measure in which another person describes the target person's behaviors, thoughts, and feelings.

Direct observation

Measuring a trait by watching and recording trait

Naturalistic observation

Direct observation of behavior in a person's normal, real

Biodata (life outcome data)

Records about a person's life used as possible indicators of personality, such as GPA, phone use, or speeding tickets.

Advantage of self

and observer reports

Limitation of direct observation

It is time

Limitation of biodata

A life outcome can be influenced by many circumstances and traits, so it may not be a pure indicator of one personality trait.

Interrater reliability versus convergent validity

Interrater reliability involves interchangeable raters observing the same thing; convergent validity compares different methods or perspectives that should measure the same trait.

Personality trait

An individual difference in a typical tendency to behave, think, or feel in conceptually related ways, across relevant situations and over a fairly long time.

Individual differences

Differences between people in their relative levels of a characteristic.

Typical tendency

A trait reflects a likelihood or predisposition, not a guarantee that someone will always act a certain way.

Conceptually related behaviors

Different behaviors, thoughts, and feelings that share an underlying psychological element.

Cross

situational consistency

Long

term stability of traits

Mental abilities versus personality traits

Mental abilities measure maximum performance, while personality traits describe typical ways of behaving, thinking, and feeling.

Beliefs and attitudes versus personality traits

Beliefs and attitudes are directed toward specific objects or issues, while traits are broader tendencies.

Situationism

The view that situations, rather than stable personality traits, largely determine behavior.

Walter Mischel

A major situationist who argued that low consistency of behavior across situations limited the usefulness of broad traits.

Mischel and Peake's finding

Different conscientiousness

Aggregation

Averaging behavior across many relevant situations to obtain a more reliable measure of a trait.

Why aggregation matters

It reduces situation

Current trait view

Situations strongly affect behavior in a specific moment, but traits predict average behavior across many situations.

Person effect

Variation in behavior due to stable differences between individuals; this is the variance explained by traits.

Situation effect

Variation in behavior caused by the situation itself.

Person × situation interaction

Variation caused by different people responding differently to the same situation.

Situation selection

People influence their experiences by choosing situations that fit their personalities.

Situation evocation

People influence their experiences by eliciting reactions from others that help create particular situations.

Structured personality inventory

A questionnaire with a predetermined set of items and fixed response options used to assess personality traits.

Personality inventory scale

A group of items whose scores are combined to measure one trait.

Item

A single question or statement in a personality inventory.

Why inventories use multiple items

Multiple related items improve reliability and cover different aspects of a trait.

Regular

keyed item

Reverse

coded item

Purpose of reverse

coded items

Acquiescence response bias

A tendency to agree with statements generally, which can distort scale scores.

Empirical strategy of test construction

Selecting items because they predict an external criterion believed to indicate the trait.

External criterion

An outside outcome or characteristic used to select test items in the empirical strategy.

Advantage of empirical strategy

Items may be hard to fake because they do not have to look obviously related to the trait.

Limitation of empirical strategy

Selected items may work differently in a new sample or may depend heavily on the chosen criterion.

Factor

analytic strategy

Factor analysis

A statistical method that identifies groups of items that tend to go together and likely reflect a common trait.

Advantage of factor

analytic strategy

Limitation of factor

analytic strategy

Rational strategy of test construction

Writing and selecting items that are theoretically relevant to a clearly defined trait.

Advantage of rational strategy

It is simpler to use and allows broad coverage of the intended trait.

Limitation of rational strategy

Obvious items may be easier for people to fake, and the scale can miss important aspects the writer did not include.

Most common modern construction strategy

The rational approach, often combined with factor analysis and empirical evidence.

California Psychological Inventory (CPI)

An empirically constructed inventory measuring socially recognizable traits and predicting outcomes such as academic performance or delinquency.

Hogan Personality Inventory (HPI)

An inventory similar to the CPI, designed especially to predict job

16 Personality Factor Questionnaire (16PF)

An inventory measuring 16 personality factors that can also be used to obtain Big Five scores.

Eysenck Personality Questionnaire (EPQ)

An inventory measuring extraversion, neuroticism, and psychoticism; often used in biological personality research.

Myers

Briggs Type Indicator (MBTI)

NEO Personality Inventory (NEO

PI

NEO Five

Factor Inventory (NEO

Big Five Inventory (BFI)

A brief personality inventory measuring the five broad personality traits.

International Personality Item Pool (IPIP)

A public pool of more than 2,000 personality items that can be used to build many personality scales.

HEXACO Personality Inventory

Revised (HEXACO