From Blame to Punishment: Disrupting Prefrontal Cortex Activity Reveals Norm Enforcement Mechanisms

• Authors: Joshua W. Buckholtz, Harvard University; Justin W. Martin, Vanderbilt University; Michael T. Treadway, Emory University; Katherine Jan, Vanderbilt University; David H. Zald, Vanderbilt University; Owen Jones, Vanderbilt University; Rene Marois, Vanderbilt University
• Journal Title: Neuron
• Volume: Volume 87, Number 6
• Publisher: Elsevier (Cell Press): 12 month embargo | 2015-09-23, Pages 1369-1380
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.neuron.2015.08.023
• Subjects: Health Sciences, Mental Health; Biology, Neuroscience; Psychology, Behavioral
• Keywords: Adolescent; Adult; Female; Humans; Magnetic Resonance Imaging; Male; Prefrontal Cortex; Punishment; Reaction Time; Social Norms; Transcranial Magnetic Stimulation; Young Adult

Abstract

The social welfare provided by cooperation depends on the enforcement of social norms. Determining blameworthiness and assigning a deserved punishment are two cognitive cornerstones of norm enforcement. Although prior work has implicated the dorsolateral prefrontal cortex (DLPFC) in norm-based judgments, the relative contribution of this region to blameworthiness and punishment decisions remains poorly understood. Here, we used repetitive transcranial magnetic stimulation (rTMS) and fMRI to determine the specific role of DLPFC function in norm-enforcement behavior. DLPFC rTMS reduced punishment for wrongful acts without affecting blameworthiness ratings, and fMRI revealed punishment-selective DLPFC recruitment, suggesting that these two facets of norm-based decision making are neurobiologically dissociable. Finally, we show that DLPFC rTMS affects punishment decision making by altering the integration of information about culpability and harm. Together, these findings reveal a selective, causal role for DLPFC in norm enforcement: representational integration of the distinct information streams used to make punishment decisions. Buckholtz et al. use inhibitory brain stimulation and fMRI to show that DLPFC involvement in norm enforcement is selective for punishment behavior over blameworthiness judgments. Behavioral modeling suggests that DLPFC integrates representations of harm and culpability to determine appropriate sanctions.