Judgments of risk frequencies: Tests of possible cognitive mechanisms

How do people judge which of 2 risks claims more lives per year? The authors specified 4 candidate mechanisms and tested them against people's judgments in 3 risk environments. Two mechanisms, availability by recall and regressed frequency, conformed best to people's choices. The same mechanisms also accounted well for the mapping accuracy of estimates of absolute risk frequencies. Their nearly indistinguishable level of performance is remarkable given their different assumptions about the underlying cognitive processes and the fact that they give rise to different expectations regarding the accuracy of people's inferences. The authors discuss this seeming paradox, the lack of impact of financial incentives on judgmental accuracy, and the dominant interpretation of inaccurate inferences in terms of biased information processing.