Abstract

People continuously have to take decision in context of uncertainty, through processes that can be modelled as Bayesian inferences. It has been observed that we tend to take more rational decision when the relevant information is expressed in form of natural frequencies, instead of percentages. This “facilitating effect of natural frequenciesµ raised the attention of the scientific community, starting a lively discussion. This work aims at providing a critical depiction of the debate over natural frequencies, framing the theoretical and experimental aspects. The target is to underline the critical issues that are still present nowadays, and their impact on future research in the field. To achieve that goal, firstly we clarify the notion of “natural frequencyµ, separating it from other related concepts, such as “normalized frequencyµ. Secondly, we explore the repercussions of the use of natural frequencies on Bayesian reasoning, considering clinical trials as an example. Thirdly, we describe two different theoretical frameworks which have been proposed to explain the facilitating effect of natural frequencies, the Ecological Rationality and Nested-Set, comparing their respective affinities and weak points. Fourthly, we underline the critical points that still need to be faced when discussing the topic. Lastly, we conclude by canvassing some potential perspectives for future research