Neuroimaging study links brain activity in the prefrontal cortex to certain psychopathic traits

Could a brain scan identify who is and isn’t a psychopath? New neuroimaging research has found that some patterns of brain activity during moral judgments are associated with psychopathic traits.

“Moral judgment refers to how appropriate one’s behavior is within the context of what is right and wrong. We use this process daily when trying to do the right thing. The ability to engage in moral judgment is a pillar of interhuman relations,” said study author Amir Gandjbakhche, a senior investigator and head of the Section on Analytical and Functional Biophotonics of the National Institute of Child Health and Human Development.

“There are ‘moral judgment’ instances where decisions can cause harm to the person and their environment. Differences in moral judgment responding are seen in antisocial personality disorder (ASPD), commonly referred to as ‘psychopathy’ in popular culture.”

“Until recently, only clinical interviews and self-reported psychological tests have been used to study psychopathic traits in relation to moral judgement. But new imaging techniques such as functional magnetic resonance imaging (fMRI) and functional near-infrared spectroscopy (fNIRS) can be used to assess psychopathic traits as they relate to moral judgement tasks, adding knowledge about how brain activation may relate to these behaviors,” Gandjbakhche explained.

“Because all individuals exhibit psychopathic traits in some capacity, the challenging question is whether we can establish a baseline for typical individuals. Having these baselines allows us to compare these measurements to individuals whose behaviors have been classified as ‘psychopaths’ and potentially provide intervention outcome measures or future therapeutic targets.”

In an initial study published in the journal Brain and Behavior, the researchers used fNIRS to examine brain activity in 33 healthy participants while they made moral judgements in various hypothetical situations. They were particularly interested in an area of the brain known as the prefrontal cortex, a region involved in planning, decision making, and learning.

Gandjbakhche and his colleagues found that different types of moral dilemmas and different types of decisions were associated with different brain responses. Brain activity in the left dorsolateral area of the prefrontal cortex was significantly higher when a nonutilitarian decision was made in an impersonal moral dilemma.

Next, the researchers examined how brain activity in the prefrontal cortex was related to psychopathy. Their study, published in Behavioural Brain Research, found that the psychopathic traits of coldheartedness and carefree non-planfulness were associated with activity in the left dorsolateral prefrontal cortex and ventromedial prefrontal cortex during personal moral judgements.

On the other hand, the psychopathic traits of Machiavellian egocentricity, rebellious nonconformity, coldheartedness, and carefree non-planfulness were associated with activity in the right lateral prefrontal cortex and a small area of ventromedial prefrontal cortex during impersonal moral judgements.

“Our study presents data and results that shed light on how functional neural activity and behavior may be tied. We expect that fNIRS can eventually be used to assess disorders that manifest in behaviors that reflect psychopathic traits, such as antisocial personality disorder, conduct disorder, etc,” Gandjbakhche told PsyPost.

“This project will potentially assist in the creation of a tool that allows for early detection of psychopathic traits, which may lead to improved diagnoses, treatments, and preferable outcomes for patients and society.”

An example of an impersonal moral dilemma is the classic trolley dilemma, in which participants are asked if they would flip a switch to divert a runaway trolley. Flipping the switch results in one person being killed, but five other people being saved.

In a personal version of this dilemma, the participants are asked if they would push a large stranger in front of the runaway trolley. The stranger will die, but his body will stop the trolley and save five people.

“All individuals have some psychopathic traits. These are very complex psychological constructs and are associated with many neural interconnected mechanisms,” Gandjbakhche explained to PsyPost.

“fNIRS can be used to find patterns of neural activity that are associated with specific behaviors, namely different levels of psychopathic traits demonstrated by participants. Our study used fNIRS to find prefrontal brain regions that are involved in moral decision making and relate to these psychopathic traits.”

Scientific research always includes some limitations, and the new studies are no exceptions. Gandjbakhche and his colleagues have made some headway in linking brain activity to psychopathic traits, but more research is needed.

“We are part of a vast scientific research effort which is just beginning to understand how the brain processes moral judgment scenarios. A large number of factors contribute to making a moral judgement, such as the environment and genetics, to name a few. These many factors force us to be careful in characterizing and diagnosing antisocial personality traits,” Gandjbakhche explained.

“Subclinical traits of antisocial personality that all of us have cannot be generalized to clinically significant levels of antisocial personality disorder and thus cannot be used for these purposes. We will continue to contribute to this field of research by developing more accessible and portable measures of brain activity to study clinical populations and healthy individuals.”

“This will allow, for example, a more detailed characterization on how moral judgment and other cognitive processes evolve in individuals with antisocial personality disorder and healthy adults across the lifespan. We should always remember that science is not purely for classification or differentiation, but for helping human beings live a better life,” Gandjbakhche said.

“We hope that one day, our research will help specific populations, for example the prison population. Incarcerated individuals have higher rates of antisocial personality traits, which our research has shown may be related to moral judgment making and associated brain activation patterns. There is potential for these behavioral and biological metrics to help inform rehabilitation efforts to decrease recidivism rates and encourage integration into society.”

The study, “Canonical correlation analysis of brain prefrontal activity measured by functional near infra-red spectroscopy (fNIRS) during a moral judgment task“, was authored by Hadis Dashtestani, Rachel Zaragoza, Hamed Pirsiavash, Kristine M. Knutson, Riley Kermanian, Joy Cui, J. Douglas Harrison Jr., Milton Halem, and Amir Gandjbakhche.