Randomness beliefs and decisions on risky medical treatments

Theoretical predictions entails that subjective beliefs of randomness affect the aggregation of medical outcomes of multiple-play medical treatments. Particularly, those who believe in more repetition of random events would tend to believe that multiple-play treatments are riskier medical interventions. As a consequence the level of repetition bias could reduce (increase) the willingness to accept or recommend multiple-play medical treatments if people are risk averse (risk prone). On the contrary, the repetition bias is expected to not affect single-play treatments. In an experiment we find evidence for these theoretical predictions by exploiting the between individual variation in the repetition bias for risk averse and risk prone subjects and by analysing hypothetical decisions of the Spanish general population for medical treatments in single and multiple-play scenarios. Consequences for individual decision making in the health context are considered as well as for the interpretation of the differences between single vs. multiple play treatments in previous studies.