Set for Probabilistic Thinking
Wright and Phillips proposed that some respondents approached uncertainty in nonprobabilistic terms. They used both frequent certainty judgments and frequent expressions of not knowing to motivate the idea; those responses alone do not establish whether confidence was well calibrated.
THE IDEA
Set for Probabilistic Thinking
Wright and Phillips (1980) argued that their Asian respondents were especially susceptible to a certainty illusion, a tendency to hold beliefs with absolute certainty. They offered this proposal because of the high frequency with which their Asian respondents reported 100% probability judgments that their chosen answers to general-knowledge questions were correct. The incidence rates for such judgments were generally more than twice as high for their participants in Asia (e.g., Malaysian students, Hong Kong businessmen) as for those in Britain. Similar differences were observed in the general-knowledge study of Yates et al. (1989). The rates of 100% judgments for the American and Japanese participants in that study were 22.6% and 21.4%, respectively, whereas the corresponding rate for the mainland Chinese participants was 47.7%.
Wright and Phillips did not attribute the certainty illusion to across-the-board assuredness; instead, they proposed that the illusion is merely one manifestation of a set to view the world in nonprobabilistic terms. Another manifestation of that set is quite different. In another task, Wright and Phillips (1980) asked participants to respond in an open-ended fashion to questions about various issues (e.g., “Will you catch a head cold in the next three months?”). Consistent with the notion of cross-cultural variations in a set for probabilistic thinking, Wright and Phillips’s Asian respondents generally offered more than twice as many “Don’t know” responses to such questions than did their British respondents.
The probabilistic thinking set idea has some intuitive appeal. Moreover, it raises a variety of interesting additional questions: One concerns how different sets might have arisen in different parts of the world, and another asks how the decision strategies of people with nonprobabilistic sets cope with the actual probabilistic nature of the world.
When to use it
Evaluating risk in investment decisions, where overconfidence might lead to excessive risk-taking or underconfidence to missed opportunities.
Cross-cultural management training to understand why team members from different backgrounds might express varying levels of certainty.
Designing surveys or polls that account for cultural tendencies toward extreme or moderate responses.
Personal growth: identifying one's own pattern of certainty or uncertainty in predictions to improve judgment calibration.
FROM THEORY TO EVERYDAY LIFE
In practice
Certainty illusion in general knowledge
Wright and Phillips’s Malaysian student and Hong Kong businessman samples reported 100% confidence on general-knowledge questions more than twice as often as the British sample. Assessing overconfidence also requires comparing those judgments with answer accuracy.
Don't know responses in personal predictions
When asked open-ended questions such as "Will you catch a head cold in the next three months?", the Asian samples gave more responses expressing uncertainty than the British sample. Such responses do not by themselves demonstrate underconfidence.
A MOMENT TO REFLECT
Put it to work.
Think of a decision you made with high certainty. Was it justified by evidence, or might you have fallen into the certainty illusion?
Why might a nonprobabilistic set be adaptive in some contexts but maladaptive in others? Give a specific example.
How could cultural differences in probabilistic thinking affect international business negotiations or teamwork?
References
- Cultural variation in probabilistic thinking (study on certainty illusion and set for probabilistic thinking) — Wright, G. and Phillips, L.D. (1980)
- Cross-cultural study on probability judgments in general knowledge — Yates, J.F. et al. (1989)
CONTINUE THE CONVERSATION
Source texts
- Heuristics and Biases The Psychology of Intuitive Judgment (Thomas Gilovich, Dale Griffin, Daniel Kahneman)