Within-person variation in psychological qualities and their assessment
Lecture 3, Psych 350 - R. Chris Fraley
http://www.yourpersonality.net/psych350/fall2013/
Personality Processes
• Many of the questions that are asked in psychology are
concerned with differences between people.
• Examples:
– Are people who were physically abused as children more likely
than those who were not to develop symptoms of
psychopathology?
– Are people who have warm and supportive relationships with
their parents more likely than those who do not to be viewed as
“good friends” among their peers?
– Are people who play violent video games more likely than those
who do not to behave aggressively toward people in real life?
• It is not adequate to merely study people who play violent
video games and examine their rate of their aggressive
behavior.
• Why?
Behaves aggressively
Plays Violent Video Games
No
Yes
No
3
Yes
7
7/10 aggressive
• Answer: The counterfactual or comparison is missing.
• Thus, we compare people who do and people who do not play
violent video games and study their relative rates of aggressive
behavior. [2x2 lasers]
Between Persons Research
• This approach is typically referred to as nomothetic or
between-persons research.
• Why? Because the comparisons are made with respect to
different people; the differences are between persons.
• Nonetheless, we often assume that the association in question
exists at the individual level too. (If people who play violent
video games are more likely than those who do not to behave
aggressively, presumably, for a given person, he or she will
behave more aggressively on days on which he or she plays
violent games compared to those days on which he or she does
not.)
• Is this reasonable?
– Maybe
• Is it logically and statistically sound?
– No
• Ecological fallacy – a logical fallacy, originally discussed in
ecology, in which inferences about individuals are based
exclusively on aggregate statistics about groups.
High
Low
Aggressive behavior
Low
High
Violent video game playing
High
Low
Aggressive behavior
Low
High
Violent video game playing
High
Low
Aggressive behavior
Low
High
Violent video game playing
High
Low
Aggressive behavior
Low
High
Violent video game playing
High
Low
Aggressive behavior
Low
High
Violent video game playing
Summary
• To summarize:
• The between-persons association between two variables does
not necessarily provide evidence for the association between
those variables within persons.
• (And the flipside of this, of course, is that evidence of an
association within a person does not provide evidence for that
association between people.)
Ideographic
• As a result, many psychologists (especially in personality
psychology) attempt to understand associations within
individuals.
• Ideographic or within-persons focus:
• If it doesn’t work a certain way for you, why should you care?
Ideographic Methods
• There are many methods for studying the way in which
psychological processes work for specific individuals.
– Various terms: daily diary methods, experience sampling,
ambulatory assessment, momentary ecological assessment
• Assess two or more psychological variables for a given person
and examine the way in which those variables are related to one
another within that person’s life.
• On days in which I’m the happiest, what am I doing?
• Does the quality of my relationship with my wife impact my
productivity at work?
• Do I perform better on exams when I study on a regular basis or
when I cram before exams?
• Does my weight vary as a function of eating X, Y, and Z? How
much weight should I expect to gain if I eat a pint of Ben and
Jerry’s?
• My moods vary a lot. What kinds of events predict that
variation?
• What kinds of daily events predict the quality of my sleep and
the content of my dreams?
Major Project 2 - Ideographic Analyses
• One of the major projects you’ll be completing in this course
involves within-person analyses.
• Specifically, you’ll be responsible for
– Selecting a research question involving three or more variables
– Collecting data on yourself over 30 days
– Analyzing those data to reach conclusions about the association
between variables in your own life
Personality Processes
• To assist in collecting and analyzing the data, we will use a
web-based system called yourPersonality.
• Go to http://www.yourpersonality.net/qs350/ to login.
• Login using your class alias/ID (first week labs) as your User
Name and your corresponding password
• Our labs this week will focus on using yourPersonality and
getting you started on the project.
• So please think between now and Friday what kind of questions
you’d like to answer about yourself.
• Fri: (Homework due) Exploring yourPersonality and practice
making modules. Begin making the modules for your project.