TY - JOUR

T1 - Reducing demand for ineffective health remedies

T2 - overcoming the illusion of causality

AU - MacFarlane, Douglas

AU - Hurlstone, Mark John

AU - Ecker, Ulrich

PY - 2018/12/2

Y1 - 2018/12/2

N2 - Objective: We tested a novel intervention for reducing demand for ineffective health remedies. The intervention aimed to empower participants to overcome the illusion of causality, which otherwise drives erroneous perceptions regarding remedy efficacy.Design: A laboratory experiment adopted a between-participants design with six conditions that varied the amount of information available to participants (N = 245). The control condition received a basic refutation of multivitamin efficacy, whereas the principal intervention condition received a full contingency table specifying the number of people reporting a benefit vs. no benefit from both the product and placebo, plus an alternate causal explanation for inefficacy over placebo.Main outcome measures: We measured participants’ willingness to pay (WTP) for multivitamin products using two incentivized experimental auctions. General attitudes towards health supplements were assessed as a moderator of WTP. We tested generalisation using ratings of the importance of clinical-trial results for making future health purchases.Results: Our principal intervention significantly reduced participants’ WTP for multivitamins (by 23%) and increased their recognition of the importance of clinical-trial results.Conclusion: We found evidence that communicating a simplified full-contingency table and an alternate causal explanation may help reduce demand for ineffective health remedies by countering the illusion of causality.

AB - Objective: We tested a novel intervention for reducing demand for ineffective health remedies. The intervention aimed to empower participants to overcome the illusion of causality, which otherwise drives erroneous perceptions regarding remedy efficacy.Design: A laboratory experiment adopted a between-participants design with six conditions that varied the amount of information available to participants (N = 245). The control condition received a basic refutation of multivitamin efficacy, whereas the principal intervention condition received a full contingency table specifying the number of people reporting a benefit vs. no benefit from both the product and placebo, plus an alternate causal explanation for inefficacy over placebo.Main outcome measures: We measured participants’ willingness to pay (WTP) for multivitamin products using two incentivized experimental auctions. General attitudes towards health supplements were assessed as a moderator of WTP. We tested generalisation using ratings of the importance of clinical-trial results for making future health purchases.Results: Our principal intervention significantly reduced participants’ WTP for multivitamins (by 23%) and increased their recognition of the importance of clinical-trial results.Conclusion: We found evidence that communicating a simplified full-contingency table and an alternate causal explanation may help reduce demand for ineffective health remedies by countering the illusion of causality.

U2 - 10.1080/08870446.2018.1508685

DO - 10.1080/08870446.2018.1508685

M3 - Journal article

SP - 1472

EP - 1489

JO - Psychology and Health

JF - Psychology and Health

SN - 0887-0446

ER -