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Title page for ETD etd-12022011-130033


Type of Document Master's Thesis
Author Kim, Joseph Un
Author's Email Address dwqkim@gmail.com
URN etd-12022011-130033
Title Orbitofrontal cortex lesions attenuate affective biases in economic decision-making
Degree Master of Arts
Department Psychology
Advisory Committee
Advisor Name Title
David H. Zald Committee Chair
Bruce D. McCandliss Committee Member
Sohee Park Committee Member
Keywords
  • framing effect
  • orbitofrontal cortex
  • decision-making
  • prospect theory
  • lesion
  • emotion
Date of Defense 2011-11-28
Availability unrestricted
Abstract
The orbitofrontal cortex has been speculated to play an important role in the processes that allow emotional factors to influence decision-making. In recent neuroimaging studies, orbitofrontal activity patterns have been linked to framing bias susceptibility in economic choice-behavior. However, it is still unclear whether orbitofrontal function directly contributes to the emergence of such observed framing bias. Hence, in the current study, we sought to examine the effect of orbitofrontal cortex (OFC) lesions on framing bias by investigating economic choice-behavior of twelve OFC lesion patients using a financial decision-making task. Results showed OFC lesion patients exhibit marked reduction in framing bias, which indicated OFC lesions disrupt processes that adapt choice-behavior to contrasting affective contexts. Furthermore, OFC lesion patients were no more likely than controls to choose the gamble option over the sure option and vice versa in the task overall, which suggested that their reduced framing bias was neither due to generalized disinhibition of risk-taking tendencies, nor a broad and nonspecific shift in choice-preference irrespective of framing manipulations. Critically, OFC lesion patients revealed deficits in adjusting their choices according to varying reward magnitude and distinct relative reward values. This study provides key evidence in support of the hypothesis that the orbitofrontal cortex serves a critical role in guiding economic decision-making by integrating salient information about the affective context of potential choices.
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