Research News

The brain’s role in violence; Vanderbilt researcher examines how brain science could affect legal responsibility

[Media Note: Vanderbilt has a campus broadcast facility with a dedicated fiber optic line for live TV interviews and a radio ISDN line. A high resolution photo of Owen Jones is available at]

A man with no prior history of sexual misconduct was caught trying to molest a child. A brain scan found that he had a large tumor pressing on his right frontal cortex. When the tumor was removed, he no longer wanted to molest children. A suicidal man tried to kill himself with a crossbow. When the arrow went into his skull, the damage done to his prefrontal cortex reversed his anti-social tendencies. A surgeon carved his name in his patient’s stomach, but was not legally punished because he was found to have a mental disorder seemingly caused by degeneration of his frontal and anterior temporal cortices.

All these scenarios raise the question, how much do we really know about the criminal mind and should laws and punishments be affected by abnormal brain form or function? If so, how and how much?

A new essay co-authored by Vanderbilt professor Owen Jones, who is one of the nations’s few professors of both law and biology, concludes that there is ample evidence to suggest different brain dysfunctions or diseases can contribute to anti-social and even criminal behavior.

“Certainly not all criminal or violent behaviors are caused by dysfunctional brains,” said Jones. “But getting a better understanding of how neurological damage could affect violent criminal behavior and recidivism is an important step in continuing efforts to refine criminal law and punishment.”

Researchers have shown that the brain’s prefrontal cortex is neurologically active when making rational deliberations, following rules, or making moral judgments. People with damage to their prefrontal cortex may know right from wrong, but they may not be able to use that knowledge when choosing how to behave. And early damage to the orbito-frontal cortex appears to make it much harder for a person to learn moral and social rules later on.

“Ongoing research by many scientists is opening a Pandora’s Box of questions on whether and when a defendant should be considered criminally insane or legally responsible for his or her criminal behavior,” said Jones. “But while science may help, simple answers are unlikely.”

For example, Jones said just because a person has damage to his or her prefrontal cortex does not mean the person will be violent. Prefrontal cortex damage often results in personality changes, but not everyone with such damage becomes unduly aggressive, and not every instance of excessive aggression traces to brain abnormalities.

“Ultimately, we need further research to better understand the pivotal role that brain architecture and function play in a person’s perceptions, choices, and actions – and the way that knowledge might be used to help make law more effective, fair and efficient,” said Jones.

Jones stressed that, at this point, brain imaging is a still-developing field. He believes much more work needs to be done, on the law side, to enable standardized and sensible interpretations of results, as well as careful and constructive discussion of possible legal implications.

“Law, Responsibility, and the Brain” can be found in the May edition of PLOS Biology.

For more news about Vanderbilt, visit the News Service homepage at

Media Contact: Amy Wolf, (615) 322-NEWS