Wilson and Brekke Model of Mental Contamination
The Wilson and Brekke model describes how unwanted mental processes (e.g., stereotyping, advertising effects, misattribution) contaminate judgments, and outlines the conditions required for detection and correction, including awareness, motivation, accurate theories, and control.
THE IDEA
THE WILSON AND BREKKE MODEL
The Wilson and Brekke model of contamination (illustrated in Figure 10.1) explains how judgments become tainted by unwanted mental processes, such as racial prejudice, advertising effects, halo effects, or misattribution. Contamination begins when an unwanted mental process is triggered. To avoid contamination, people must first detect that it exists—a difficult task because mental processes are largely inaccessible (Nisbett & Wilson, 1977b). Unlike physical contamination (e.g., spoiled milk), judgments do not show overt signs of taint; as Wilson and Brekke (1994) wrote, 'Human judgments – even very bad ones – do not smell' (p. 121).
Detection may rely on indirect clues, such as an unexpected reaction (e.g., disliking a highly touted candidate) that triggers thoughts about bias, or a salient potential contaminant. People often rely on lay theories about bias; for example, an unexpected negative reaction to a job candidate might be attributed to racism only if the person has a theory about that bias. White male supervisors are unlikely to attribute a negative reaction to a white male from Des Moines to prejudice.
Once contamination is suspected, correction requires three conditions: (1) motivation to correct the error, (2) awareness of the direction and magnitude of the bias, and (3) sufficient control over responses to adjust the judgment. The main causes of mental contamination include: (1) lack of awareness of mental processes, (2) lack of control over mental processes, (3) inaccurate theories about unwanted influences, and (4) inadequate motivation to correct.
Numerous biases can be viewed as mental contamination, including automatic stereotyping, unwanted effects of accessible information (priming), effects of persuasive communications (advertising), and misattribution of arousal.
When to use it
Hiring decisions where unconscious bias (e.g., race, gender) might affect evaluations of candidates.
Consumer decisions influenced by advertising or sales tactics, such as buying a product based on exaggerated claims.
Legal judgments where pretrial publicity or irrelevant information may bias jurors' perceptions of guilt.
Medical diagnoses where initial impressions (e.g., based on patient demographics) may lead to confirmation bias in subsequent tests.
FROM THEORY TO EVERYDAY LIFE
In practice
Racial Prejudice in Hiring
Ms. Green evaluates Mr. Jones for a job and gives him a negative evaluation. She suspects this might be due to racial prejudice. However, she cannot directly observe whether her judgment is tainted, and must rely on indirect clues (e.g., the unexpectedness of her reaction) and her lay theories about racism to detect contamination. Even if detected, she must decide how much to correct and whether she has enough control to override her initial impression.
Advertising Influence on Purchases
A consumer buying a product based on exaggerated claims may not realize their judgment is contaminated by advertising. They might only suspect bias if they notice an unexpected emotional reaction or if the advertising is particularly salient. Correction would require awareness of the influence, motivation to resist, and the ability to adjust their evaluation.
A MOMENT TO REFLECT
Put it to work.
Think of a time you suspected your judgment was biased by an unwanted influence. How did you detect it? What steps did you take to correct it?
What lay theories do you hold about common biases (e.g., racism, advertising effects)? How might those theories help or hinder your ability to detect contamination in your own thinking?
Consider a decision where you tried to correct for bias but were unsure how much to adjust. How did you decide the magnitude of correction? Was it effective?
References
- Mental contamination and debiasing — Wilson & Brekke (1984)
- Telling more than we can know: Verbal reports on mental processes — Nisbett & Wilson (1977)
- The influence of accessible information on judgments — Stapel, Martin, & Schwarz (1998)
- The elaboration likelihood model of persuasion — Petty & Wegener (1993)
- Attitudes and attitude change — Wegener & Petty (1997)
CONTINUE THE CONVERSATION
Source texts
- Heuristics and Biases The Psychology of Intuitive Judgment (Thomas Gilovich, Dale Griffin, Daniel Kahneman)