Law-abiding folks can be stunned by an unforgivable crime or the perpetrator’s callous response to it. Often, the only explanation is that the criminal is a psychopath, a condition marked by shallow emotions, insincerity and a lack of empathy.

The condition is an acute concern in the U.S. prison system. While only 1 percent of Americans are diagnosed as psychopaths, the condition afflicts as many as 30 percent of prisoners.

But science might be on the verge of explaining the physiology of a psychopathic brain.

In a new study, neuroscientists peeked inside the brains of 80 incarcerated psychopaths. For the study, the psychopathic prisoners were confronted with a series of scenes that typically generate an empathic response in a normal person. For example, some of the scenarios included situations where a person was being intentionally hurt.

Meanwhile, the prisoners’ brain activity was measured using MRI technology. Researchers found that the areas of the brain that trigger empathy or emotional learning did not behave normally in the psychopaths.

The psychopathic brain, researchers determined, is hardwired differently. Having concern for others is not in their skillset.

Empathy is such a basic component of the human experience that even babies show characteristics of it, such as crying when other babies cry. Recent research has even suggested that empathy is even present among rodents.

Yet everyone from psychologists to prison wardens has long known that the psychopaths who fill prisons show little empathy. Perhaps the knowledge that psychopaths don’t have the same brain function that most humans are born with will bring doctors one step closer to treating the condition, and society a step closer to managing one of the most critical issues in criminal justice.