Written By Dominic Ibarra Javonillo
In the 19th century, Franz Joseph Gall introduced an idea that would change the relationship between our physical body and mental mind. This idea was “phrenology,” an approach that measures ridges and bumps in the skull to acquire meaningful information about one’s personality. Like palm reading, phrenology is not supported by much empirical data, yet its popularity grew as it became fashionable to visit phrenologists in the 19th century . However, the practice lost its popular appeal and scientific authority in the turn of the next century. Despite this, phrenology had introduced a notion that eerily still persists today. What is the relationship between the brain and human nature (i.e. behavior)? How do physical brain changes affect mental mind changes? With the advent of brain scanning technologies such as functional magnetic resonance imaging (fMRI), researchers have been able to locate active brain areas while individuals perform certain tasks and behaviors. Many research fields have begun correlating areas of the brain with particular behaviors using fMRI. One of these emerging fields is neurocriminology, which seeks to answer a classic question about the brain and human nature: how can brain abnormalities lead to criminal behavior?
In January, Darby et al. published a neurocriminology study that sheds light on the brain’s relationship with criminal behavior. Prior to the Darby et al. study, there have been other findings of damaged brain regions that correlate with violent, criminal behavior. Past studies have analyzed this behavior by studying head injuries, brain lesions, and structural neuroimaging . These studies provided strong evidence that damage to frontal lobe of the brain corresponds with violence and aggression . However, Darby et al. points out that it is unclear whether lesions to the frontal lobe and related areas either cause, result from, or correlate with criminality . Rather than limiting their view to isolated islands of damaged brain regions, Darby et al. uses a new technique called “lesion network mapping” to determine that these damaged islands are connected through a network of neural bridges.
Looking at resting brain regions and their functional connections to each other, the group found that the separate brain lesions of their 17 criminal subjects were all connected in one network—that is, these regions each collectively carry out the same function . With this network in mind, Darby et al. found that these regions were also connected to brain areas active during moral tasks and moral decision-making . However, the most significant point of their study was their investigation into opponent networks that negatively correlate with criminal behavior. Darby et al. found that their identified network positively correlated with decisions against harm and negatively correlated with regions activated by practical decisions to incite harm onto others . This study’s findings may be better understood if one imagines a major airport with connecting flights to other smaller airports. If, for some reason, the major airport is closed, all the connecting flights would not reach the smaller airports. Likewise, damage to these competing networks offer a reason why previous studies have found abnormalities in brain areas linked to criminal behavior. Ultimately, Darby et al. found that by combining the two competing networks, one might effectively predict criminal behavior when brain damage to these networks occur.
Of course, the thought of making predictions based on brain abnormalities raises many important ethical questions. What should be done to individuals who have these abnormalities? Do criminals with these brain abnormalities have free will? Where does accountability for their crimes lie? While these questions may not have solid answers, they do encourage discussion and dialogue over criminal behavior. Certainly, this discourse would provide valuable insight for criminal legislation and law enforcement by identifying these unique and extreme circumstances like brain abnormalities. With intersections in philosophy and law, neurocriminology is one of the many fields in which scientific research may drive important social changes for all.
 The Shape of Your Head and the Shape of Your Mind. (2014, January 6). The Atlantic.
 Bannon S.M., Salis K.L., O’Leary K.D. 2015. Structural brain abnormalities in aggression and violent behavior. Aggression and Violent Behavior. 25:323-31.
 Darby R.R., Horn A., Cushman F., Fox M.D. 2018. Lesion network localization of criminal behavior. PNAS. 15:601-6.