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An experimental approach to examine behavior and brain activity during decision-making under risk as compared to ambiguity
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  • Benjamin Albrecht,
  • Johannes Hewig,
  • Patrick Mussel,
  • Isabell Welpe,
  • Angela Stanton,
  • Wolfgang Miltner
Benjamin Albrecht
Julius Maximilians University Würzburg
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Johannes Hewig
Julius Maximilians University Würzburg

Corresponding Author:[email protected]

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Patrick Mussel
Freie Universität Berlin
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Isabell Welpe
Technische Universität München
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Angela Stanton
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Wolfgang Miltner
Friedrich Schiller University Jena
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Neural correlates of decisions under risk and under ambiguity have been examined for several decades. In the current study, we focus on a neglected aspect that is a potential confounding of the average risk of alternatives in a trial, the average magnitude of the outcomes, and the difference in risk between the two alternatives. We present an experimental approach to solve this problem here and explicitly separate risk and ambiguity. In the present fMRI-study with 20 participants, we created different levels of risk and ambiguity to investigate their effects on behavior and brain activation. In a first experimental block, decisions with mixed-risk options (one high-risk option paired with one low-risk option) were compared to decisions with two high-risk or two low-risk options in terms of the effects on decision-making and neural activity. The second block consisted of the same risk levels crossed with high and low ambiguity by withholding information about the probabilities of the outcomes. During mixed-risk trials participants made cautious decision significantly more often. This effect was strongest during mixed trials with high ambiguity in the second block. In addition, risk behavior of subjects was correlated with the subjective importance of the amount of potential monetary losses or wins and the related probabilities. The fMRI results revealed activation of the dorsal anterior cingulate cortex (dACC), the insula, and the orbitofrontal cortex (OFC) during mixed risk trials without ambiguity. In contrast, activation of the amygdala was specifically present during mixed-risk trials with high ambiguity.
09 May 2023Submitted to Psychophysiology
30 Oct 2023Assigned to Editor
30 Oct 2023Submission Checks Completed
30 Oct 2023Review(s) Completed, Editorial Evaluation Pending
12 Nov 2023Reviewer(s) Assigned