Betrayal and unfairness are linked through insula-valuation network dynamics

Area of Science:

• Social Neuroscience
• Neuroeconomics
• Cognitive Neuroscience

Background:

• Cooperation relies on trust and fairness, yet neural bases for violations of these social norms are often studied in isolation.
• Understanding how the brain processes different types of social norm violations is crucial for comprehending social behavior.

Purpose of the Study:

• To investigate whether neural sensitivity to betrayal in one social context predicts responses to unfairness in a separate context.
• To explore the neural mechanisms underlying the generalization of sensitivity to interpersonal norm violations.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan 132 adults during the Trust Game and Ultimatum Game.
• Analysis focused on regional brain activation and functional connectivity, particularly within the anterior insula and ventromedial prefrontal cortex.
• Cross-task analyses examined individual differences in neural responses to social and nonsocial stimuli.

Main Results:

• Both betrayal and unfairness activated overlapping regions in the left anterior insula, but individual differences in activation were uncorrelated across tasks.
• Connectivity patterns differed: stronger anterior insula responses to social betrayal predicted weaker anterior insula-ventromedial prefrontal coupling during fairness evaluation.
• These findings suggest a network-level mechanism for generalizing sensitivity to interpersonal norm violations, rather than a simple shared regional response.

Conclusions:

• Betrayal and unfairness are linked not by identical regional responses but by how salience signals engage valuation circuitry across contexts.
• The study reveals a network-level architecture for generalizing sensitivity to interpersonal norm violations, bridging canonical social exchange tasks.
• This research advances our understanding of the neural basis of social decision-making and norm compliance.