Reduced decision bias and more rational decision making following ventromedial prefrontal cortex damage

Sanjay Manohar; Patricia Lockwood; Daniel Drew; Sean James Fallon; Trevor T-J Chong; Deva Sanjeeva Jeyaretna; Ian Baker; Masud Husain

doi:10.1016/j.cortex.2021.01.015

Reduced decision bias and more rational decision making following ventromedial prefrontal cortex damage

Cortex. 2021 May:138:24-37. doi: 10.1016/j.cortex.2021.01.015. Epub 2021 Feb 11.

Authors

Sanjay Manohar¹, Patricia Lockwood², Daniel Drew³, Sean James Fallon⁴, Trevor T-J Chong⁵, Deva Sanjeeva Jeyaretna⁶, Ian Baker⁷, Masud Husain⁸

Affiliations

¹ Nuffield Dept of Clinical Neurosciences, University of Oxford, UK; Dept of Experimental Psychology, University of Oxford, UK; Department of Neurology, John Radcliffe Hospital, Oxford, UK. Electronic address: [email protected].
² Centre for Human Brain Health, University of Birmingham, UK; Dept of Experimental Psychology, University of Oxford, UK.
³ Nuffield Dept of Clinical Neurosciences, University of Oxford, UK.
⁴ National Institute for Health Research Bristol Biomedical Research Centre, University Hospitals, Bristol NHS Foundation Trust and University of Bristol, UK.
⁵ Turner Institute for Brain and Mental Health, Monash University, Victoria 3800, Australia.
⁶ Nuffield Dept of Clinical Neurosciences, University of Oxford, UK; Department of Neurosurgery, John Radcliffe Hospital, Oxford, UK.
⁷ Department of Neurology, John Radcliffe Hospital, Oxford, UK.
⁸ Nuffield Dept of Clinical Neurosciences, University of Oxford, UK; Dept of Experimental Psychology, University of Oxford, UK; Department of Neurology, John Radcliffe Hospital, Oxford, UK.

Abstract

Human decisions are susceptible to biases, but establishing causal roles of brain areas has proved to be difficult. Here we studied decision biases in 17 people with unilateral medial prefrontal cortex damage and a rare patient with bilateral ventromedial prefrontal cortex (vmPFC) lesions. Participants learned to choose which of two options was most likely to win, and then bet money on the outcome. Thus, good performance required not only selecting the best option, but also the amount to bet. Healthy people were biased by their previous bet, as well as by the unchosen option's value. Unilateral medial prefrontal lesions reduced these biases, leading to more rational decisions. Bilateral vmPFC lesions resulted in more strategic betting, again with less bias from the previous trial, paradoxically improving performance overall. Together, the results suggest that vmPFC normally imposes contextual biases, which in healthy people may actually be suboptimal in some situations.

Publication types

Case Reports

MeSH terms

Bias
Brain
Decision Making*
Gambling*
Humans
Prefrontal Cortex / diagnostic imaging

Abstract

Publication types

MeSH terms

Grants and funding