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

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Bibliographic Details
Title:	A neural mechanism underlying failure of optimal choice with multiple alternatives.
Authors:	Chau, Bolton K H, Kolling, Nils, Hunt, Laurence T, Walton, Mark E, Rushworth, Matthew F S
Source:	Nature Neuroscience. Mar2014, Vol. 17 Issue 3, p463-470. 8p. 1 Diagram, 6 Graphs.
Subjects:	Magnetic resonance imaging, Magnetic resonance, Frontal lobe, Prefrontal cortex, Diagnostic imaging
Abstract:	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. [ABSTRACT FROM AUTHOR]
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Database:	Psychology and Behavioral Sciences Collection

Description
Abstract:	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. [ABSTRACT FROM AUTHOR]
ISSN:	10976256
DOI:	10.1038/nn.3649