Chapter Two Methods in the Study of Personality

Gathering Information About Personality Informal Sources of Information: Observations of Self—Introspection, self- reflection, self-attention –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

Generalizability 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

Correlational Method A relationship in which the values of two variables go together in a meaningful way Features of a Correlation –Direction –Strength

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 (y) axis. –Knowledge of score on one dimension leads to prediction of other dimension

Ways to Characterize a Correlation Quantitative –Correlation coefficient (r) –Positive correlation: When high values of one variable are associated with high values of another variable –Negative correlation: When high values of one variable are associated with low values of another variable 0+1 (non-existent) (strongest negative) (strongest positive)

Strength of the Correlation Accuracy of predictive value or “sloppiness” Perfect positive Moderate positive Weak positive Perfect negative Moderate negative Weak negative

Significance 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 Self-esteem Athletic ability Third Variable

Experimental Method Used to make inferences about causality How it works: –By creating a situation in which the researcher can control and manipulate differences in a variable(s). She can then observe the effects of these differences.

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 explanations –Allows regulation of temporal sequence of events Can infer causality

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

Multifactor Studies Objective: –To examine the combined effect (interaction) of two or more variables on an outcome variable Types –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