Verbal and Numerical Expressions of Probability: ªIt's a Fifty±Fifty Chanceº

When estimating risks, people may use ª50º as an expression of the verbal phrase ªfifty±fifty chance,º without intending the associated number of 50%. The result is an excess of 50s in the response distribution. The present study examined factors determining the magnitude of such a ª50 blip,º using a large sam-ple of adolescents and adults. We found that phrasing probability questions in a distributional format (asking about risks as a per-centage in a population) rather than in a singular format (asking about risks to an individual) reduced the use of ª50.º Less numer-ate respondents, children, and less educated adults were more likely to say ª50.º Finally, events that evoked feelings of less per-ceived control led to more 50s. The results are discussed in term