How prior preferences determine decision-making frames and biases in the human brain

Alizée Lopez-Persem,Philippe Domenech,Mathias Pessiglione

doi:10.7554/elife.20317

Abstract

Understanding how option values are compared when making a choice is a key objective for decision neuroscience. In natural situations, agents may have a priori on their preferences that create default policies and shape the neural comparison process. We asked participants to make choices between items belonging to different categories (e.g., jazz vs. rock music). Behavioral data confirmed that the items taken from the preferred category were chosen more often and more rapidly, which qualified them as default options. FMRI data showed that baseline activity in classical brain valuation regions, such as the ventromedial Prefrontal Cortex (vmPFC), reflected the strength of prior preferences. In addition, evoked activity in the same regions scaled with the default option value, irrespective of the eventual choice. We therefore suggest that in the brain valuation system, choices are framed as comparisons between default and alternative options, which might save some resource but induce a decision bias.

Highlights

Standard decision theory assumes that when faced with a choice, individuals first assign subjective values to each option, and compare these values in order to select the best option (Samuelson, 1938; Von Neumann and Morgenstern, 1947)
We analyze choices and response times to assess the presence of a bias in favor of the default option
We examined how prior preference shapes the neural representation of decision value

Summary

Introduction

Standard decision theory assumes that when faced with a choice, individuals first assign subjective values to each option, and compare these values in order to select the best option (Samuelson, 1938; Von Neumann and Morgenstern, 1947). Neural activity in the vmPFC reflects subjective values, either measured with likeability ratings or inferred from binary choices (Kable and Glimcher, 2009; Rangel and Hare, 2010). (Chib et al, 2009; Hare et al, 2010; Lebreton et al, 2009; Plassmann et al, 2007) Such value coding was observed during choice and in the absence of choice, during passive viewing of items presented in the attentional focus or when performing a distractive task on these items (Lebreton et al, 2009; Levy et al, 2011; Abitbol et al, 2015)

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