Delayed synergies are harder to see: an experimental investigation of factors influencing synergistic judgements of health risks
When certain health hazards are combined, they produce synergies. In other words, they lead to risks that are greater than the sum of risks presented by each factor separately. For instance, smoking and radon exposure interact synergistically to increase lung cancer risk. Without doubt, how people judge such risk combinations is important – and previous research showed mostly underestimation of synergistic risks. Our previous research instead suggests that people are better at judging certain synergistic risks as such than others. In the current pre-registered study, we aim to understand why this is the case. In particular, we experimentally test whether the likelihood of judging a combination of risk factors as synergistic depends on the outcome being immediate or delayed, binary or continuous, or whether knowledge about the outcome plays a role. We find that synergistic judgements are much more likely for immediate outcomes compared to the delayed ones. Thanks to the structure of our data, we are also able to shed light on the possible mechanism for this. In particular, our data suggest that this result is due to the difference in how much weight people give to the single risk factors for immediate vs delayed outcomes, not to how they evaluate the combination of risk factors. Our study furthermore tests for the effects of format of the task. We find that synergistic judgements are more likely if natural frequencies and partitive probabilities are used, as opposed to non-partitive (single-case) probabilities. These results have important implications for communications concerning synergistic health risks.
Prof. David Comerford
Economics Division, Stirling Management School, University of Stirling, FK9 4LA.
(+44 / 0) 75-42-188-166
Director, Behavioural Science Centre
Program Director, MSc Behavioural Science
Recent publications:
Bridger, E. K., Tufte-Hewett, A., & Comerford, D. A. (2023). Perceived health inequalities: are the UK and US public aware of occupation-related health inequality, and do they wish to see it reduced?. BMC Public Health, 23(1), 2326.
Comerford, D. A., Tufte-Hewett, A., & Bridger, E. K. (2023). Public preferences to trade-off gains in total health for health equality: Discrepancies between an abstract scenario versus the real-world scenario presented by COVID-19. Rationality and Society, 10434631231193599.