A team of scientists in Spain is getting ready to experiment on prisoners. If the scientists get the necessary approvals, they plan to start a study this month that involves placing electrodes on inmates’ foreheads and sending a current into their brains. The electricity will target the prefrontal cortex, a brain region that plays a role in decision-making and social behavior. The idea is that stimulating more activity in that region may make the prisoners less aggressive.
This technique — transcranial direct current stimulation, or tDCS — is a form of neurointervention, meaning it acts directly on the brain. Using neurointerventions in the criminal justice system is highly controversial. In recent years, scientists and philosophers have been debating under what conditions (if any) it might be ethical.
The Spanish team is the first to use tDCS on prisoners. They’ve already done it in a pilot study, publishing their findings in Neuroscience in January, and they were all set to implement a follow-up study involving at least 12 convicted murderers and other inmates this month. On Wednesday, New Scientist broke news of the upcoming experiment, noting that it had approval from the Spanish government, prison officials, and a university ethics committee. The next day, the Interior Ministry changed course and put the study on hold.