Exploring the Impact of the Sunk-Cost Bias on Health-Threatening Behavior

Theoretical Background and research questions/hypothesis: Modern decision theory suggests that rational choices should not be influenced by prior sunk costs.  The sunk-cost bias results in individuals choosing a suboptimal choice, relative to a more attractive option. Notably, few studies have investigated the potential impact of the sunk-cost bias on health related decisions. The current study addresses this gap in knowledge. We predicted that young adults would be more likely to engage in a health threatening behavior when they’ve incurred a sunk cost.

Methods:  Two hundred and eighty two participants, ages 19 -25, were randomly assigned to one of four groups: 1) sunk cost incurred with no risk of harm; 2) no sunk cost incurred with no risk of harm; 3) no sunk cost incurred but with risk of harm; 4) sunk cost incurred but with risk of harm.  All participants read five hypothetical scenarios describing social or health-related behavior that young adults might engage in. After reading each scenario, participants indicated if they would choose the riskier option or the safer option in both the sunk cost and non-sunk cost scenarios.

Results:  A sunk cost bias was revealed in responses in two of the five scenarios that did not require health related decisions. Similarly, a sunk cost bias was revealed in responses to one of the five scenarios that required health related decisions.

Conclusions:  A sunk cost bias was not consistently revealed in either of the above contexts (i.e., health related and non-health related).  These findings are not consistent with prior research on the sunk cost bias.  Notably, the current study represents the first attempt to investigate the impact of the sunk-cost bias on health-related decisions. Future research should investigate the conditions under which health threatening decisions made by young adults are influenced by prior irretrievable costs.

Implications for research and/or practice:  Individuals should be reminded that regardless of the health choices that they make, sunk-cost are irrecoverable and should not influence their health related decisions.