This project examined the variables that mediate the relationship between the exogenous variables numerical presentation and numeracy and the endogenous variables risk perception and risk related decisions. Previous research suggested that numerical format and numeracy influence outcomes. The question that remained unanswered was why? The goal of this project was to peer into the proverbial black box to critically examine information processing at work.
To examine possible mediating variables, two theoretical models that have emerged in the risk perception literature were tested. The first is an evolutionary theory proposing that over time, individuals have developed an augmented ability to process frequency information. Thus, frequency information should be clearer and people should be faster at forming risk perceptions with information in this format. According to this model, processing speed and evidence clarity mediate the relationship between evidence format and risk perception. A second framework, the affective processing theory, argues that frequency information is more vivid and people derive more affect from information in this format. Therefore, according to this model, affect and vividness mediate the relationship between presentation format and risk perception. In addition to these two perspectives, a third theory was proposed and tested. The integrated theory of risk information processing predicted that reaction time, clarity, affect, and vividness would all influence risk perception.
Two experiments were conducted to test the predictions of these three theories. Overall, some support for an integrated model was found. Results indicated that the mediating variables reaction time, clarity, affect, and vividness had direct effects on risk perception. In addition, risk perception had a strong influence on risk related decisions. In Study 2, objective numeracy had a direct effect on reaction time, such that people with high numeracy spent more time forming risk evaluations. Furthermore, people with a preference for numerical information evaluated numerical evidence as clearer and more vivid than people who preferred to receive evidence in nonnumerical formats. Both theoretical and applied implications of these results are discussed and recommendations for future research are provided
