How can we answer questions about personality scientifically? Personality Research Methods
Self-Identification Survey
Personality Research Methods Goals – 1. Most generally, to become more sophisticated consumers of research information 2. To understand how we study personality empirically 3. To appreciate strengths and weaknesses of various designs and analyses – what they can and can’t tell us about personality 4. Be able to interpret some key types of statistics
Personality Research Methods What is the purpose of research? To, as objectively as possible: • Evaluate theories • Answer practical questions
In general, to accumulate knowledge in an objective and public manner
Personality Research Methods Three topics: • Research design • Interpreting data (statistics) • Measurement (personality assessment, already covered)
Personality Research Methods Research Design Two broad kinds of questions in research – 1) Is X related to Y? • Are SAT scores related to GPA scores? • Is emotional expressivity related to physical health?
2) Does X cause Y? • Does medication cause symptom reduction? • Does child abuse cause Borderline PD? • Do genes determine sexual orientation?
Causality is “the big question”
Personality Research Methods Research Designs Types of research design • Experimental • Passive • Case Study
Personality Research Methods Research Design Experimental Design – • Manipulate a variable (IV) and measure changes in another variable (DV). • Random assignment to conditions (levels of IV). • Strengths and Limitations - Discuss
Personality Research Methods Research Design Passive Designs – • Observe (measure) how pre-existing differences between people on one variable are related to differences between those people on another variable • E.g., drug abuse and psychological adjustment
• Why “Passive”? • Strengths and Limitations – discuss
Personality Research Methods Research Design Case Studies – • In depth analysis of specific entities (a person, a group, an organization) • Eg, Charles Whitman; Freud - the case of Little Hans; Allport – “Letters From Jenny”; • Strengths and limitations - discuss
Personality Research Methods Research Design Personality Psychology often uses Passive Designs Why?
Is Extraversion related to popularity? Is Drug Abuse related to psychological adjustment?
Personality Research Methods Three topics: • Research design • Interpreting data (statistics) • Measurement (personality assessment, already covered)
Personality Research Methods Interpreting Data Statistics are nothing but tools to help us make sense out of data. We will typically: • Look for group differences on some variable • Look for relationships among variables
At one level, these are the same things.
Your BFI Data A few questions to answer: • Is personality related to happiness? • Are there sex differences in personality? • Is personality related to GPA? • Do these associations/differences differ by trait? But first – how do we quantify/describe associations/differences?
Personality Research Methods Interpreting Data Why worry about this? • General sophistication in critical thinking? • Ability to understand studies that we’ll be discussing Two general kinds of statistics: 1. Descriptive Statistics 2. Inferential Statistics
Personality Research Methods Interpreting Data Two general kinds of statistics: 1. Descriptive Statistics – • •
To summarize/describe the data that was collected in a sample of subjects. Examples – frequencies, means, standard deviations, correlation
Your BFI Data A few questions to answer: • Is personality related to happiness? • Are there sex differences in personality? • Is personality related to GPA? • Do these associations/differences differ by trait?
Personality Research Methods Interpreting Data What is a correlation? • A correlation (r) is a number that summarizes the direction and degree of association between two variables • Do people who have high SAT scores also get relatively high GPAs? • This is a question about the association between two variables: SAT score and GPA.
Personality Research Methods Interpreting Data A correlation gives two pieces of info: 1. Direction of association • + people who score relatively high on one variable tend to score relatively high on the other • - people who score relatively high on one variable tend to score relatively low on the other • 0 there is no relationship between the variables people who score relatively high on one variable are likely to score either high OR low on the other. • Note: “relatively”; “positive” ≠ good
Your BFI Data A few questions to answer: • Is personality related to happiness? • Are there sex differences in personality? • Is personality related to GPA? • Do these associations/differences differ by trait?
Personality Research Methods Interpreting Data A correlation gives two pieces of info: 2. Degree of association • •
How strongly related are the two variables? Range from +1 (Very strong positive relationship) to –1 (Very strong negative relationship) • Values closer to zero represent “weaker” relationships So what would a “strong” correlation be? .90? .30? .50?
Personality Research Methods Interpreting Data Interpreting a correlation – Is this relationship strong or weak? At least two ways to interpret the size of a corr: 1. Research context 2. Translate to Probabilities (BESD, in textbook)
Personality Research Methods Interpreting Data Two General Kinds of statistics (continued) 2. Inferential Statistics – • •
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To make statements/inferences about the population(s) of people from which the sample of subjects was drawn. “Statistical significance”. Is the result representative of the “population”? Male and female samples (20 each) – find difference in IQ. Is this representative of the “population of males and females?
Statistical vs Experimental “Control” What is experimental control? What do we want to “control” when doing an experiment? What if we can’t do so experimentally? – Statistical control? “Multiple regression”, partial correlations, etc Example Conscientiousness, SAT, and GPA Wagerman and Funder
Personality Research Methods Goals – 1. Most generally, to become more sophisticated consumers of research information 2. To understand how we study personality empirically 3. To appreciate strengths and weaknesses of various designs and analyses – what they can and can’t tell us about personality 4. Be able to interpret some key types of statistics
