The natural frequency effect (NF effect)—whereby framing health risks using information presented as natural frequencies (NFs), instead of conditional probabilities (CPs), results in improved diagnostic problem solving—has led to the recommended use of NFs in clinical practice. This experiment tests, via incentivization of a lab-based decision, the hypothesis that the NF effect reflects differential motivation applied to solving problems that differ in complexity. The study examines if incentive effects are moderated by task complexity and expertise and also explores the extent to which NF frames improve diagnostic understanding. Incentives increased correct problem solving and the NF effect was replicated. The NF effect did not vary as a function of incentivization, but was slightly attenuated by task complexity and expertise. There was no evidence that effort mediated the incentive effect. The correct PPV (which is low) was associated with reduced trust in the test’s diagnostic accuracy. For those who committed errors, NF frames increased the likelihood of underestimating the PPV, with underestimation associated with greater trust in the test. The NF effect is robust to incentives supporting the use of NF frames in clinical settings. When errors occur, however, NF frames are linked to underestimation.This network project brings together economists, psychologists, computer and complexity scientists from three leading centres for behavioural social science at Nottingham, Warwick and UEA. This group will lead a research programme with two broad objectives: to develop and test cross-disciplinary models of human behaviour and behaviour change; to draw out their implications for the formulation and evaluation of public policy. Foundational research will focus on three inter-related themes: understanding individual behaviour and behaviour change; understanding social and interactive behaviour; rethinking the foundations of policy analysis. The project will explore implications of the basic science for policy via a series of applied projects connecting naturally with the three themes. These will include: the determinants of consumer credit behaviour; the formation of social values; strategies for evaluation of policies affecting health and safety. The research will integrate theoretical perspectives from multiple disciplines and utilise a wide range of complementary methodologies including: theoretical modeling of individuals, groups and complex systems; conceptual analysis; lab and field experiments; analysis of large data sets. The Network will promote high quality cross-disciplinary research and serve as a policy forum for understanding behaviour and behaviour change.
Three-hundred and 25 participants (235 novices and 90 medical experts) were randomly allocated to a frame (NF vs. CP) by task difficulty (short vs. standard menus) by incentive (present vs. absent) between-subjects design. The task was to calculate the positive predictive value (PPV) of the hemoccult test for colorectal cancer. Effort, self-efficacy, and diagnostic understanding were assessed.
