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Money talks: neural substrate of modulation of fairness by monetary incentives.

Zhou Y, Wang Y, Rao LL, Yang LQ, Li S - Front Behav Neurosci (2014)

Bottom Line: We found evidence for a significant modulation by the proposed amount on fairness in the right lateral prefrontal cortex (PFC) and the bilateral insular cortices.Inter-individual differences in the modulation effects in the left inferior frontal gyrus (IFG) accounted for inter-individual differences in the behavioral modulation effect as measured by the rejection rate, supporting the concept that the PFC plays a critical role in making fairness-related normative decisions in a social interaction condition.Our findings provide neural evidence for the modulation of fairness by monetary incentives as well as accounting for inter-individual differences.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Behavioral Science, Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China.

ABSTRACT
A unique feature of the human species is compliance with social norms, e.g., fairness, even though this normative decision means curbing self-interest. However, sometimes people prefer to pursue wealth at the expense of moral goodness. Specifically, deviations from a fairness-related normative choice have been observed in the presence of a high monetary incentive. The neural mechanism underlying this deviation from the fairness-related normative choice has yet to be determined. In order to address this issue, using functional magnetic resonance imaging we employed an ultimatum game (UG) paradigm in which fairness and a proposed monetary amount were orthogonally varied. We found evidence for a significant modulation by the proposed amount on fairness in the right lateral prefrontal cortex (PFC) and the bilateral insular cortices. Additionally, the insular subregions showed dissociable modulation patterns. Inter-individual differences in the modulation effects in the left inferior frontal gyrus (IFG) accounted for inter-individual differences in the behavioral modulation effect as measured by the rejection rate, supporting the concept that the PFC plays a critical role in making fairness-related normative decisions in a social interaction condition. Our findings provide neural evidence for the modulation of fairness by monetary incentives as well as accounting for inter-individual differences.

No MeSH data available.


Related in: MedlinePlus

Brain activations influenced by fairness and proposer type at proposal presentation. (A) Maps of the t statistics for the contrast [unfair > fair] showing activation of the bilateral insula, ACC, and lateral PFC, and for the contrast [fair > unfair] showing activation of the medial prefrontal cortex. (B) Map of the t statistic for the contrast [human > computer] showing activation of the bilateral insula, ACC, medial prefrontal cortex and lateral PFC. Abbreviations: ACC, anterior cingulate cortex; PFC, prefrontal cortex.
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Figure 3: Brain activations influenced by fairness and proposer type at proposal presentation. (A) Maps of the t statistics for the contrast [unfair > fair] showing activation of the bilateral insula, ACC, and lateral PFC, and for the contrast [fair > unfair] showing activation of the medial prefrontal cortex. (B) Map of the t statistic for the contrast [human > computer] showing activation of the bilateral insula, ACC, medial prefrontal cortex and lateral PFC. Abbreviations: ACC, anterior cingulate cortex; PFC, prefrontal cortex.

Mentions: A significant main effect of fairness was found in several brain regions. Specifically, the bilateral insula, ACC, lateral PFC showed greater activation for unfair proposals than for fair proposals, whereas the medial prefrontal cortex showed greater activation for fair proposals than for unfair proposals (p < 0.05, cluster-level correction) (Table 2 and Figure 3A). A significant main effect of proposer type was also found, in which the bilateral insula, ACC, medial prefrontal cortex, lateral PFC were more activated in the human proposer condition than in the computer proposer condition (p < 0.05, cluster-level correction) (Table 2 and Figure 3B). No significant main effect of stake size was found (p < 0.05, cluster-level correction).


Money talks: neural substrate of modulation of fairness by monetary incentives.

Zhou Y, Wang Y, Rao LL, Yang LQ, Li S - Front Behav Neurosci (2014)

Brain activations influenced by fairness and proposer type at proposal presentation. (A) Maps of the t statistics for the contrast [unfair > fair] showing activation of the bilateral insula, ACC, and lateral PFC, and for the contrast [fair > unfair] showing activation of the medial prefrontal cortex. (B) Map of the t statistic for the contrast [human > computer] showing activation of the bilateral insula, ACC, medial prefrontal cortex and lateral PFC. Abbreviations: ACC, anterior cingulate cortex; PFC, prefrontal cortex.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4017157&req=5

Figure 3: Brain activations influenced by fairness and proposer type at proposal presentation. (A) Maps of the t statistics for the contrast [unfair > fair] showing activation of the bilateral insula, ACC, and lateral PFC, and for the contrast [fair > unfair] showing activation of the medial prefrontal cortex. (B) Map of the t statistic for the contrast [human > computer] showing activation of the bilateral insula, ACC, medial prefrontal cortex and lateral PFC. Abbreviations: ACC, anterior cingulate cortex; PFC, prefrontal cortex.
Mentions: A significant main effect of fairness was found in several brain regions. Specifically, the bilateral insula, ACC, lateral PFC showed greater activation for unfair proposals than for fair proposals, whereas the medial prefrontal cortex showed greater activation for fair proposals than for unfair proposals (p < 0.05, cluster-level correction) (Table 2 and Figure 3A). A significant main effect of proposer type was also found, in which the bilateral insula, ACC, medial prefrontal cortex, lateral PFC were more activated in the human proposer condition than in the computer proposer condition (p < 0.05, cluster-level correction) (Table 2 and Figure 3B). No significant main effect of stake size was found (p < 0.05, cluster-level correction).

Bottom Line: We found evidence for a significant modulation by the proposed amount on fairness in the right lateral prefrontal cortex (PFC) and the bilateral insular cortices.Inter-individual differences in the modulation effects in the left inferior frontal gyrus (IFG) accounted for inter-individual differences in the behavioral modulation effect as measured by the rejection rate, supporting the concept that the PFC plays a critical role in making fairness-related normative decisions in a social interaction condition.Our findings provide neural evidence for the modulation of fairness by monetary incentives as well as accounting for inter-individual differences.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Behavioral Science, Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China.

ABSTRACT
A unique feature of the human species is compliance with social norms, e.g., fairness, even though this normative decision means curbing self-interest. However, sometimes people prefer to pursue wealth at the expense of moral goodness. Specifically, deviations from a fairness-related normative choice have been observed in the presence of a high monetary incentive. The neural mechanism underlying this deviation from the fairness-related normative choice has yet to be determined. In order to address this issue, using functional magnetic resonance imaging we employed an ultimatum game (UG) paradigm in which fairness and a proposed monetary amount were orthogonally varied. We found evidence for a significant modulation by the proposed amount on fairness in the right lateral prefrontal cortex (PFC) and the bilateral insular cortices. Additionally, the insular subregions showed dissociable modulation patterns. Inter-individual differences in the modulation effects in the left inferior frontal gyrus (IFG) accounted for inter-individual differences in the behavioral modulation effect as measured by the rejection rate, supporting the concept that the PFC plays a critical role in making fairness-related normative decisions in a social interaction condition. Our findings provide neural evidence for the modulation of fairness by monetary incentives as well as accounting for inter-individual differences.

No MeSH data available.


Related in: MedlinePlus