Scores on the three-item Cognitive Reflection Test (CRT) have been linked with dual-system theory and normative decision making (Frederick, 2005). In particular, the CRT is thought to measure monitoring of System 1 intuitions such that, if cognitive reflection is high enough, intuitive errors will be detected and the problem will be solved. However, CRT items also require numeric ability to be answered correctly and it is unclear how much numeric ability vs. cognitive reflection contributes to better decision making. In two studies, CRT responses were used to calculate Cognitive Reflection and numeric ability; a numeracy scale was also administered. Numeric ability, measured on the CRT or the numeracy scale, accounted for the CRT's ability to predict more normative decisions (a subscale of decision-making competence, incentivized measures of impatient and risk-averse choice, and self-reported financial outcomes); Cognitive Reflection contributed no independent predictive power. Results were similar whether the two abilities were modeled (Study 1) or calculated using proportions (Studies 1 and 2). These findings demonstrate numeric ability as a robust predictor of superior decision making across multiple tasks and outcomes. They also indicate that correlations of decision performance with the CRT are insufficient evidence to implicate overriding intuitions in the decision-making biases and outcomes we examined. Numeric ability appears to be the key mechanism instead.

Background Previous research demonstrated that providing (vs. not providing) numeric information about medications’ adverse effects (AEs) increased comprehension and willingness to use medication, but left open the question about which numeric format is best. Objective To determine which of four tested formats (percentage, frequency, percentage+risk label, frequency+risk label) maximizes comprehension and willingness to use medication across age and numeracy levels. Design In a cross-sectional internet survey (N=368; American Life Panel, 5/15/08–6/18/08), respondents were presented with a hypothetical prescription medication for high cholesterol. AE likelihoods were described using one of four tested formats. Main outcome measures were risk comprehension (ability to identify AE likelihood from a table) and willingness to use the medication (7-point scale; not likely=0, very likely=6). Results The percentage+risk label format resulted in the highest comprehension and willingness to use the medication compared to the other three formats (mean comprehension in percentage + risk label format=95% vs mean across the other three formats = 81%; mean willingness= 3.3 vs 2.95, respectively). Comprehension differences between percentage and frequency formats were smaller among the less numerate. Willingness to use medication depended less on age and numeracy when labels were used. Limitations Generalizability is limited by use of a sample that was older, more educated, and better off financially than national averages. Conclusions Providing numeric AE-likelihood information in a percentage format with risk labels is likely to increase risk comprehension and willingness to use a medication compared to other numeric formats.

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