How Fair Sanctions Are Orchestrated in the Brain

The new findings could also be significant for therapeutic use in psychiatric and forensic patients.

Civilized human cohabitation requires us to respect elementary social norms. We guarantee compliance with these norms with our willingness to punish norm violations – often even at our own expense. This behaviour goes against our own economic self-interest and requires us to control our egoistic impulses.

In collaboration with Professor Ernst Fehr, Doctor Thomas Baumgartner and Professor Daria Knoch reveal the neuronal networks behind self-control. For the purposes of their study, they combined the transcranial magnetic stimulation (TMS) method with functional magnetic resonance imaging (fMRI).

The results of the study show that people only punish norm violations at their own expense if the dorsolateral prefrontal cortex – an important area for control located at the front of the brain – is activated. This control entity must also interact with another frontal region, the ventromedial prefrontal cortex, for punishment to occur.

The communication between these two frontal regions of the brain is also interesting in light of earlier fMRI studies, which showed that the ventromedial prefrontal cortex encodes the subjective value of consumer goods and normative behaviour. Baumgartner explains, it seems plausible that this brain region might also encode the subjective value of a sanction. This value increases through the communication with the dorsolateral prefrontal cortex. “Using brain stimulation, we were able to demonstrate that the communication between the two brain regions becomes more difficult if the activity in the dorsolateral prefrontal cortex is reduced. This in turn makes punishing norm violations at your own expense significantly more difficult.”

The results could be important in the therapeutic use of the non-invasive brain-stimulation method in psychiatric and forensic patients. Patients who exhibit strong anti-social behaviour also frequently display reduced activity in the ventromedial prefrontal cortex. This region of the brain, however, is not directly accessible for non-invasive brain stimulation, as its location is too deep inside the brain. The results of the current study suggest that the activity in this region of the brain could be increased if the activity in the dorsolateral prefrontal cortex were increased with the aid of brain stimulation. “This indirectly induced increase in the activity of the frontal brain regions could help improve pro-social and fair behaviour in these patients,” concludes Knoch.; Source: University of Zurich