Commentary: Utility-free heuristic models of two-option choice can mimic predictions of utility-stage models under many conditions

Citation: Padoa-Schioppa C (2015) Commentary: Utility-free heuristic models of two-option choice can mimic predictions of utility-stage models under many conditions. A Commentary on Utility-free heuristic models of two-option choice can mimic predictions of utility-stage models under many conditions. Many neuroeconomic studies in the past 10 years have reported neural signals encoding the subjective value (or utility) of offered and chosen goods The precise mechanisms through which values are compared to make a decision remain unclear and are matter of current research. However, the fact that neurons in the orbitofrontal and ventromedial prefrontal cortices encode the subjective value of offered and chosen goods, taken together with the fact that lesions to these same areas selectively disrupt economic decisions (Camille et al., 2011), strongly suggests that economic choices are ultimately based on these value signals These results are generally viewed as a significant breakthrough compared to standard and behavioral economic theories, where subjective value (or utility) enters as an " as if " concept. In a recent paper, Piantadosi and Hayden (2015) challenge this understanding. Goods available for choice can generally vary on multiple dimensions (or attributes), and by definition subjective values integrate all the dimensions relevant to the decision. The authors first examine the specific case in which choices are made between two options that depend only on quantity and probability (two parametric dimensions). Building on an argument originally put forth by Tversky (1969), they show that decisions based on an integrated utility (algorithm 1) cannot be distinguished from decisions based on a utility-free heuristic (algorithm 2). According to this second algorithm, subjects would first identify the attribute with highest variance and then choose according to that attribute alone (dimensional prioritization). This heuristic does not include the computation of any utility. The authors go on to claim that the same argument applies very broadly to binary decisions between goods that vary on two or more dimensions, provided that the dimensions are decomposable into additive functions. In the last part of the paper, they claim that similar arguments apply to neural data and that neural signals previously found to encode subjective value " may arise artifactually from utility-free heuristic processes. " The paper is interesting for it highlights one of the challenges in linking a behavioral choice or a neural signal to the computation of subjective values. Importantly, if the algorithm of Piantadosi and Hayden applied as broadly as the authors claim …