When making decisions, people must frequently take into account numerical information, but not all individuals have the ability to understand and use numbers. Less numerate individuals comprehend less numerical information; but numeracy goes beyond comprehension, relating systematically to psychological mechanisms. In particular, greater numeracy has been associated with reduced susceptibility to framing effects, less influence of nonnumerical information such as mood states, and greater sensitivity to different levels of numerical risk. This greater number sensitivity has been linked with number-related affective reactions reported by the highly numerate. I briefly discuss methods to increase number use in decisions and policy implications of numeracy research.
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