A neural mechanism underlying failure of optimal choice with multiple alternatives.

Journal article

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.

Authors: Chau, B; Kolling, N; Hunt, LT; Walton, M; Rushworth, M

• Publication status: Published
• Journal: Nature neuroscience
• Volume: 17
• Issue: 3
• Pages: 463-470
• Publication date: 2014-03-01
• DOI: 10.1038/nn.3649
• EISSN: 1546-1726
• ISSN: 1097-6256
• Language: English
• Keywords: Young Adult; Neural Networks (Computer); Humans; Adult; Male; Prefrontal Cortex; Attention; Psychomotor Performance; Decision Making; Magnetic Resonance Imaging; Functional Neuroimaging; Female