Personality psychology chapter2 methods in the study of personality

Establishing Relationships among Variables • Variable: dimension along which people differ • Levels – Examples: low vs.. Ways to Characterize a Correlation • Graphical: – Representation

Gathering Information About

Personality

Informal Sources of Information:

• Observations of Self—Introspection, reflection, self-attention

self-– Danger = bias, lack of self-awareness

• Observations of Others

– Danger = possibility of misinterpretation

Gathering Information About

Personality

Formal Methods

• Case study

• Experience sampling

Case Study

Intensive examination of a single person

• Advantages:

– In-depth knowledge

– Information pertains to normal life

– Context of discovery and verification

• Disadvantages

– Very limited generalizability

Experience Sampling

• AKA diary studies

• Conducted across extended periods of time

• Use self-reports

– Multiple observations at prompts

– People do not have to remember far back in time

• Possible to search for patterns within a given person across situations

• Ability to apply a conclusion to a

broad range of people

– Generalizability is best when:

• Data are from many people

• Data are from different types of people (e.g., age, gender, race, SES, culture)

– Implication for generalizability of research with college students?

Establishing Relationships among

Variables

• Variable: dimension along which people differ

• Levels

– Examples: low vs high self-esteem, sex

– Must have at least two values

Ways to Characterize

a Correlation

• Graphical:

– Representation of two

variables, with one

variable plotted on the

horizontal (x) axis and

the other variable

plotted on the vertical

(strongest positive)

Strength of the Correlation

• Accuracy of predictive value or “sloppiness”

0 1 2 3 4 5 6 7

0 2 4 6

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0 2 4 6 0

0 2 4 6

0 1 2 3 4 5 6 7

0 2 4 6 0

Perfect positive Moderate positive Weak positive

Perfect negative Moderate negative Weak negative

• Index of believability or meaningfulness of

relationship

• Statistical significance suggests a relationship

is unlikely to be the result of chance

• Clinical or practical significance indicates that the observed relationship has meaningful,

real-world consequences

Advantages of Correlational

Methods

• Often quick and efficient

• Often the only method available

– For practical reasons (can’t assign personality)– For ethical reasons (can’t get strong levels of some variables—e.g., anxiety)

• Provides a quantitative index

Limitation of Correlation

• Can’t infer causation

– Directionality problem

– Third variable problem

Third Variable

Characteristics of

an Experiment

• Manipulation of variables

• Random assignment to conditions

• Exertion of experimental control

• Measurement of effects of manipulation

Elements of the Experiment

• Independent variable

– The variable the researcher manipulates

• Conceptual definition (e.g., emotional support)

• Operational definition (e.g., parental verbal praise)

– The cause in the cause-and-effect relationship

• Dependent variable

– The variable the researcher measures

• Conceptual definition (e.g., academic performance)

• Operational definition (e.g., math achievement scores)

Advantages of Experimental Method

• Can exercise a high degree of control

– Allows ability to rule out third variable

Disadvantages of Experimental Method

• Often artificial situation

• Usually limited to short durations

• Manipulations must remain weak

• Some variables can’t be manipulated

• Sometimes difficult to determine what it is about the manipulation that was

responsible for the effect

• Can’t control all variables (confounds)

Comparing Types of Study

• How to identify which type of study

– Correlational: Examines variation due to

naturally occurring characteristics in groups that exist naturally

– Experimental: Examines variation due to

variation from a manipulated characteristic in groups that were assigned at random

– All manipulated variables

– All correlational variables (naturally occurring characteristics)

– Mixed variables (experimental personality)

Graphs Portraying Multifactor Research

• Main effects:

– Make general statement

about each individual

variable (e.g., class size,

sociability) and the

dependent measure

(anxiety)

• Interactions:

– Qualify the effect of one

variable on the dependent

measure by taking the

other variable into account 0

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