A neural mechanism underlying failure of optimal choice with multiple alternatives

Nat Neurosci. 2014 Mar;17(3):463-70. doi: 10.1038/nn.3649. Epub 2014 Feb 9.


Despite widespread interest in neural mechanisms of decision-making, most investigations focus on decisions between just two options. Here we adapt a biophysically plausible model of decision-making to predict how a key decision variable, the value difference signal-encoding how much better one choice is than another-changes with the value of a third, but unavailable, alternative. The model predicts a surprising failure of optimal decision-making: greater difficulty choosing between two options in the presence of a third very poor, as opposed to very good, alternative. Both investigation of human decision-making and functional magnetic resonance imaging-based measurements of value difference signals in ventromedial prefrontal cortex (vmPFC) bore out this prediction. The vmPFC signal decreased in the presence of low-value third alternatives, and vmPFC effect sizes predicted individual variation in suboptimal decision-making in the presence of multiple alternatives. The effect contrasts with that of divisive normalization in parietal cortex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Attention / physiology*
  • Decision Making / physiology*
  • Female
  • Functional Neuroimaging / methods*
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Neural Networks, Computer*
  • Prefrontal Cortex / physiology*
  • Psychomotor Performance / physiology*
  • Young Adult