1. What predicts behavior? The Person-Situation Debate
INTERNAL FORCES !
(the person)
What predicts behavior? The Person-Situation Debate
CONTEXTUAL FORCES !
(the situation)

2. SITUATIONIST CRITIQUE OF PERSONALITY:
(other names: Person-Situation Controversy; Consistency Paradox)
A controversial and painful debate that almost killed the field of personality but at the end helped to redefine and improve the concept of trait (the later, thanks to people like Bem, Funder, Buss, Winter, Cantor, Emmons, among others).
Political roots of this debate? Long-standing disagreements between clinical psychologists (Freudian, interested in intra-psychic structures --the internal!) and experimental psychologists (Radical behaviorism, interested in social, cultural forces --what can be observed!)

3. SITUATIONIST CRITIQUE OF PERSONALITY:
How did all started?
Mischel’s (1968) did an extensive review of personality studies (use of self-reports and projective tests to predict single behaviors) and found that most correlations among related measures of personality traits (e.g., honesty and conscientiousness scales) and between personality traits and related behaviors (e.g., honesty scale and cheating behavior) were only (less 10% variance).
MISCHEL’S CONCLUSION --> is the concept of trait important or useful at all?

4. SITUATIONIST CRITIQUE OF PERSONALITY:
therefore ….
Personality traits don’t influence behavior much (we overestimate people’s behavioral consistency --> personality = cognitive illusion).
At any time, people’s behavior is mainly powered by situational forces such as roles, peer pressure, ‘cues’ (priming of certain cognitions and motives), media influence, etc ...

5. PERSONALITY PSYCHOLOGY’S RESPONSE TO THIS DEBATE?
10 years later …….
Epstein (1979), Funder and Ozer's (1983) --> reanalysis of some of situationism's best known studies -> predictive power of situations had about the same size as criticized "personality coefficients"! ( )

6. 1. INTERACTIONISM PROPOSED SOLUTIONS TO CONTROVERSY
(and lessons learned from it)
1. INTERACTIONISM
Very often, a big chunck of behavioral variance (y) is predicted by the interaction between the situation (S) and personality (P), that is: PxS
BEHAVIOR (y) = P + S + PxS + error
ANALYSIS OF VARIANCE (ANOVA) MODEL

7. Example of a significant interaction effect between personality and the situation

8. BEHAVIOR (y) = P + S + PxS + error
Y = creative work performance
P = openness to experience (scores on this measure were used to divide people in two groups: HIGH and LOW Openness)
S = clerical job vs. student newspaper job
HIGH
HIGH
Creative
vs.
Uncreative behavior
LOW
HIGH
LOW
(Y)
LOW
News-paper
Clerical
Job type (S)

9. BEHAVIOR (y) = P + S + PxS + error
Y = creative work performance
P = openness to experience (scores on this measure were used to divide people in two groups: HIGH and LOW Openness)
S = clerical job vs. student newspaper job
HIGH
HIGH
In this example, only the main effects (P & S separately) are significant (the interaction between them is not significant)
Creative
vs.
Uncreative behavior
LOW
HIGH
LOW
(Y)
LOW
News-paper
Clerical
Job type (S)

10. 2. ROLE OF MODERATOR-VARIABLES
PROPOSED SOLUTIONS TO CONTROVERSY
(and lessons learned from it)
2. ROLE OF MODERATOR-VARIABLES
Individual differences in people’s need for consistency (how much importance you give to show consistency on your behavior, values, goals, etc) and self-monitoring (attention to situational cues) moderate predictive power of personality and the situation.

11. 3. AGGREGATION PROPOSED SOLUTIONS TO CONTROVERSY
(and lessons learned from it)
3. AGGREGATION
Correlations between conceptually-related traits or between traits and their related behaviors increase dramatically when these measures are aggregated (ie. averaged) across different situations, times, types of questionnaires, etc.)