PSYB30H3 Lecture Notes - Lecture 2: Predictive Validity, Personality Test, Problem Solving
PSYB30 - Introduction to Personality
Lecture 2 - Personality Assessment, Measurement, and Research Design
Personality Assessment, Measurement, and Research Design
Question
● If you wanted to know what a person was like, what would you do?
○ Questionnaires
○ Social media
○ Get data using different methods
● How could you learn about a person: observation, personality tests, experiment,
interaction, etc.
● Why would you use a particular method?
● What would you hope to learn from this method?
How Do Psychologists Study Personality?
● Scientific method - methodical process, certain steps are followed to make claims that
are reliable and valid, want to ensure reliability and validity of construct
○ Not all reliable things are valid
■ For a method to be valid it has to be reliable but not all reliable things are
valid
○ Describe how to make and test observations
○ Draw conclusions
○ Minimize errors
○ Publish results or conference with others about your conclusion
○ Tools
■ Theories
■ Predictions
■ Controlled methods
■ Independent verifications
○ Theoretical weaker than theory
● Observational studies and personality questionnaires
● Correlational and experimental designs
Research Designs in Personality
● Experimental methods
○ Used to determine causality - whether one variable causes another
○ Two key requirements:
■ Manipulation of variables
● You cannot really manipulate a trait but you can manipulate a
state measure because state is situation specific
● Personality is inherent to the individual
■ Ensuring that participants in each experimental condition are equivalent to
each other
● Random assignment ensures equality in experiments
● Correlational studies
○ Correlation is a statistical procedure for determining whether there is a
relationship between two variables, not manipulating any variables
○ Designed to identify “what goes with what” in nature, and not designed to identify
causal relationships
○ One variable tends to be associated with another variable, measure the
association
○ Major advantage is that it allows us to identify relationships among variables as
they occur naturally
○ Correlation coefficient varies from -1 (perfect negative relationships) through 0
(no relationship) to +1 (perfect positive relationship)
■ +1 -1 is a perfect relationship
■ As one variable goes up the other one goes up as well (positive)
■ As one variable goes up the other one goes down, working in opposite
directions (negative)
○ Cannot infer causality
■ You don’t know if one variable is causing the relationship to the other or if
there is a third variable
○ Correlation does not indicate causation
■ Directionally problem
■ Third variable problem
○ Size correlations
■ Small correlations range in size from 0 to -.3 and 0 to +.3 (weak
relationship)
■ Medium correlations range in size from -.3 to -.5, and +.3 to +.5
(moderate relationship)
■ Large correlations range in size from -.5 to -.9, and +.5 to +.9
● Case studies (idiographic approach)
○ In depth examination of the life of one person (idiographic)
○ Advantages
■ Can find out about personality in great detail
■ Can give insight into personality that can be used to formulate a more
general theory that is tested on a larger sample
■ Can provide in depth knowledge about an outstanding figure, such as a
political or religious figure
○ Disadvantage
■ Results based on the study of single person cannot be generalized to
others
Case Study: Justin Trudeau
● Assess the personal quality of Justin Trudeau
○ What are the essential features of the prime ministers personality?
● Important Personality Qualities?
○ Public communication
○ Organizational capacity
○ Political skill
○ Vision
○ Cognitive style
○ Emotional intelligence
● Family ties:
○ His father, Pierre Elliott Trudeau, was part way through his first term as prime
minister and had married Justin’s mother, Margaret, earlier that year
○ There were politicians on both sides of Justin’s family: maternal grandfather
James Sinclair served as minister of fisheries in the cabinet of Prime Minister
Louis St Laurent
● Spent his childhood in full view of the media
● His brother Michel died by an avalanche
● Is said to much more closely resemble his vibrant mother than his stoic father, and he
appeared destined for a life outside of Canadian politics
○ Became a school teacher
○ Gained the reputation of being a political lightweight
● Often described as “charismatic”
● His boyish, eager-to-please personality leads him to project publicly in a way that can
seem intellectually unsophisticated
When to Use Experimental, Correlational, and Case Study Designs
● Each design has strengths and weaknesses; strength of one is weakness of other
○ Based on what their research question is and what approach will give them the
best answer
● Which design a researcher uses depends on the research question and goal of research
● Taken together, three designs provide complementary methods for exploring personality
Lemon Juice Experiment
● The amount of saliva you produce after putting a drop of lemon juice on your tongue
might tell you something about your personality
● Scientists think introverts have increased activity in their reticular activating system
(RAS) and therefore increased production of saliva
○ The theory is that the RAS in introverts has a high level of activity, even when it
isn’t being stimulated
○ In extraverts, there is a low level of activity in the RAS when it isn’t stimulated, so
they required a much larger stimulus to generate a response. So they usually
Document Summary
Lecture 2 - personality assessment, measurement, and research design. How could you learn about a person: observation, personality tests, experiment, interaction, etc. Scientific method - methodical process, certain steps are followed to make claims that are reliable and valid, want to ensure reliability and validity of construct. For a method to be valid it has to be reliable but not all reliable things are valid. Describe how to make and test observations. Publish results or conference with others about your conclusion. Used to determine causality - whether one variable causes another. You cannot really manipulate a trait but you can manipulate a state measure because state is situation specific. Ensuring that participants in each experimental condition are equivalent to each other. Correlation is a statistical procedure for determining whether there is a relationship between two variables, not manipulating any variables. Designed to identify what goes with what in nature, and not designed to identify causal relationships.
