The Empathy Gap: Psychopathy, the Brain, and What the Law Does With Both

In 2005, a neuroscientist named James Fallon was studying brain scans of convicted serial killers when he noticed something unusual about one of the scans in his dataset. The pattern of activity was consistent with the others he had been analyzing: reduced function in the orbital cortex and other regions associated with empathy, moral reasoning, and impulse control. The kind of scan, in his own words, that he associated with psychopathy.

The scan belonged to him.

Fallon had included his own brain scan in the dataset without realizing it. When he went back and examined his family history, he found a long line of violent relatives, including multiple alleged murderers on his father's side. He has spent the years since trying to understand why he became a successful scientist and family man while others with similar neurology became killers. His conclusion is that he does not fully know. [1]

That uncertainty is exactly what makes psychopathy one of the most difficult problems in forensic psychiatry, and one of the most consequential ones for the law.

What Psychopathy Actually Is

Psychopathy is not a diagnosis that appears in the DSM, the manual used by psychiatrists and psychologists to classify mental disorders. The closest formal diagnosis is antisocial personality disorder, but psychopathy is a more specific construct, assessed primarily through a tool called the Psychopathy Checklist Revised, developed by Canadian psychologist Robert Hare. [2]

The checklist measures a constellation of traits across two broad dimensions. The first is interpersonal and affective: superficial charm, grandiosity, pathological lying, lack of remorse, shallow emotional responses, and a failure to empathize with the feelings or suffering of others. The second is behavioral: impulsivity, irresponsibility, poor behavioral controls, and a persistent pattern of antisocial conduct. [2]

A score above thirty on the checklist is generally used to identify psychopathy. Approximately one percent of the general population meets this threshold. Among incarcerated people, estimates range from fifteen to twenty-five percent. Among people convicted of violent offenses, the rates are higher still. [3]

Psychopathy is not the same as violence. Many people who score high on the checklist never commit crimes. They occupy positions in business, law, politics, and other fields where certain psychopathic traits, charm, fearlessness, immunity to stress, can function as advantages. The relationship between psychopathy and harmful behavior is real but not deterministic. [4]

Lens One: The Scientific Evidence

The scientific literature on psychopathy is among the most extensive in all of forensic psychology, and it points consistently in one direction: the brains of people with psychopathy are measurably different from those of people without it.

Neuroimaging studies have found reduced gray matter volume in the amygdala, the paralimbic system, and regions of the prefrontal cortex in people who score high on psychopathy measures. These differences are not subtle. They are visible on structural scans and are consistent across multiple independent research groups. [5]

Functional imaging studies have added to this picture. When people with psychopathy are shown images of others in pain or distress, the neural circuits that typically activate in response to witnessing suffering show reduced activity. The same is true when they are exposed to fear-inducing stimuli. The brain's emotional alarm system, which in most people generates an aversive response that motivates avoidance of harmful behavior, does not fire in the same way. [6]

Researcher Kent Kiehl has spent years bringing a mobile MRI unit into prisons across the United States and scanning the brains of incarcerated people. His work has consistently found that high psychopathy scores are associated with reduced activity in the paralimbic system during emotional processing tasks, and that these neurological differences are measurable, reliable, and distinct from those seen in other psychiatric populations. [7]

The scientific question that remains genuinely open is what causes these differences. Studies of twins suggest a strong heritable component. But environment also plays a significant role. Severe early childhood trauma, neglect, and abuse have been linked to the development of psychopathic traits, and researchers believe that the interaction between genetic vulnerability and environmental experience shapes the final neurological profile. [8]

Lens Two: The Neuroscience

The core neurological feature of psychopathy, as the research reveals it, is a fundamental disruption in the system that connects emotional experience to decision-making and moral reasoning.

In a brain without psychopathy, the amygdala generates emotional responses to social and moral stimuli. It registers the fear and distress of others. It produces discomfort in response to causing harm. These emotional signals are transmitted to the prefrontal cortex, where they influence judgment and shape behavior. The feeling of guilt, the aversion to cruelty, the instinctive reluctance to hurt someone, these are not purely rational constructs. They are grounded in an emotional system that provides ongoing input to the reasoning brain. [9]

In psychopathy, the connectivity between the amygdala and the prefrontal cortex is disrupted. The amygdala does not respond normally to the suffering of others. The emotional signal that most people experience as conscience does not arrive with the same force, or in some cases at all. The prefrontal cortex is left to make moral decisions without the emotional grounding that normally guides them.

This is what Fallon discovered about himself. He is capable of understanding, intellectually, that harming others is wrong. What he has described lacking is the gut-level emotional response that makes that understanding feel urgent and real. He describes himself as a pro-social psychopath, someone who has the neurological profile but whose behavior has been shaped by a stable upbringing and strong environmental supports toward constructive ends. [1]

The implication for criminal responsibility is profound and uncomfortable. The moral intuitions that most people rely on to guide their behavior are biological. They are produced by brain systems. When those systems are structurally and functionally different, the resulting moral experience is different too.

The question of whether someone whose brain does not generate normal guilt responses can be held responsible in the same way as someone whose brain does is one that neither neuroscience nor law has fully answered.

Lens Three: The Legal Interpretation

Psychopathy occupies a paradoxical position in the legal system. It is simultaneously used to deny defendants leniency and to question their fundamental moral responsibility.

In most jurisdictions, psychopathy does not qualify as a mental disease or defect sufficient to support an insanity defense. Courts have generally reasoned that psychopathy does not prevent a person from knowing that their actions are wrong, only from caring. Under the M'Naghten standard discussed in an earlier post, that distinction matters. Knowing is the threshold. Feeling is not. [10]

But psychopathy is also used by prosecutors as an aggravating factor in sentencing, particularly in capital cases. High scores on the psychopathy checklist are presented as evidence that a defendant is especially dangerous, unlikely to respond to rehabilitation, and therefore deserving of harsher punishment.

The contradiction here is significant. The legal system, in the same proceeding, can use psychopathy to argue that a person is too dangerous to deserve mercy while simultaneously refusing to recognize it as a condition that affects criminal responsibility. The neurological difference is acknowledged for the purpose of increasing punishment and dismissed for the purpose of reducing it.

The Supreme Court's decision in Kansas v. Hendricks in 1997 allowed for the indefinite civil commitment of sexually violent predators after they had completed their prison sentences, partly on the basis of diagnoses like psychopathy. [11] The Court reasoned that the commitment was civil rather than criminal and therefore did not constitute additional punishment. Critics argued that incarcerating someone indefinitely after they had served their sentence, based on a prediction of future dangerousness, was punishment in every meaningful sense.

More recently, defense attorneys have used neuroscientific evidence of psychopathic brain differences to argue for reduced sentences in capital cases, with some success. In Wiggins v. Smith in 2003 and Rompilla v. Beard in 2005, the Supreme Court found that defense attorneys had been ineffective when they failed to investigate and present neurological and psychological evidence in capital sentencing. [12] These decisions have pushed courts toward taking brain evidence more seriously, even when it does not support a full insanity defense.

Putting All Three Lenses Together

The scientific evidence establishes that psychopathy is associated with measurable, consistent neurological differences in regions responsible for empathy, emotional processing, and moral reasoning. The neuroscience explains the mechanism: disrupted connectivity between the amygdala and prefrontal cortex means that the emotional signals that normally guide moral behavior arrive weakened or not at all. The law uses this diagnosis selectively, treating it as a reason to punish more harshly while refusing to treat it as a reason to question the standard of responsibility being applied.

James Fallon's story sits at the center of what makes this problem so difficult. He has the brain, and by his own account some of the traits, associated with psychopathy. He also has a life that reflects care, contribution, and relationship. His neurology did not determine his outcome. But it shaped the terrain he was working with.

The question the law has not answered is this: if the moral emotions that anchor most people's behavior are biological, and if a person's biology produces those emotions in a fundamentally different form, what does it mean to hold that person to a standard built for a brain they do not have?

That question does not have a clean answer. It does have an honest one. And the honest one requires looking at what is actually happening in the brain, not just what we want to be true about responsibility and choice.

The next post will look at addiction, and ask a parallel question: when the brain's decision-making system has been physically altered by substance use, how much of what looks like a choice actually is one?

Sources

[1] Fallon, J., "The Psychopath Inside: A Neuroscientist's Personal Journey into the Dark Side of the Brain," 2013: jamesfallon.com

[2] Hare, R.D., "The Hare Psychopathy Checklist Revised," 2nd ed., Multi-Health Systems, 2003: mhs.com

[3] Kiehl, K.A. and Hoffman, M.B., "The Criminal Psychopath: History, Neuroscience, Treatment, and Economics," Jurimetrics, 2011: pmc.ncbi.nlm.nih.gov/articles/PMC4059069

[4] Babiak, P. and Hare, R.D., "Snakes in Suits: When Psychopaths Go to Work," HarperCollins, 2006

[5] Yang, Y. et al., "Localization of deformations within the amygdala in individuals with psychopathy," Archives of General Psychiatry, 2009: jamanetwork.com

[6] Blair, R.J.R., "The amygdala and ventromedial prefrontal cortex in morality and psychopathy," Trends in Cognitive Sciences, 2007: cell.com/trends/cognitive-sciences

[7] Kiehl, K.A., "A cognitive neuroscience perspective on psychopathy," Psychiatry Research, 2006: pubmed.ncbi.nlm.nih.gov

[8] Viding, E. et al., "Evidence for substantial genetic risk for psychopathy in 7-year-olds," Journal of Child Psychology and Psychiatry, 2005: pubmed.ncbi.nlm.nih.gov

[9] Damasio, A., "Descartes' Error: Emotion, Reason, and the Human Brain," Penguin, 1994

[10] Morse, S.J., "Psychopathy and Criminal Responsibility," Neuroethics, 2008: springer.com

[11] Kansas v. Hendricks, 521 U.S. 346 (1997): supreme.justia.com/cases/federal/us/521/346

[12] Rompilla v. Beard, 545 U.S. 374 (2005): supreme.justia.com/cases/federal/us/545/374