People with personality traits associated with narcissism, Machiavellianism, and psychopathy exhibit unique patterns of brain activity, even at rest. A recent analysis of brain scans shows that these people have increased baseline activity in areas associated with strategic planning and decreased activity in areas responsible for empathy and self-reflection. The study was published in the journal Cognitive, Affective & Behavioral Neuroscience.
Psychologists group three overlapping personality types under one umbrella known as the Dark Triad. Narcissism is a mixture of grandiosity, a deep sense of entitlement, and an underlying emotional vulnerability. Machiavellianism is characterized by ruthless, calculating manipulation and a general lack of empathy for others. Psychopathy is defined as emotional callousness combined with highly impulsive or antisocial behavior.
Although these characteristics are often studied in people with clinical diagnoses or criminal histories, they exist on a continuum across the general population. Elevated levels of these traits often correlate with antisocial behavior, prejudice, and aggression in everyday settings. Researchers have focused on the psychological and behavioral consequences of these hostile personalities. The biological basis of this triad structural model has received little attention in clinical science.
Richard Bakiasi, a researcher at the University of Trento in Italy, led a team that investigated the core neural structures that these three traits have in common. Most previous neuroimaging studies on this topic have relied on small groups of participants or on analyzing individual regions of the brain determined in advance. Bakiaj and his colleagues aimed to organically look at the whole brain to see how large-scale networks function in individuals who score high on dark personality tests. The research team wanted to determine whether these personality dimensions have common neurobiological roots.
The research team obtained cognitive and neuroimaging data from an existing database of 200 German adults. All participants in the database completed a standardized questionnaire designed to measure three dark traits. Individuals in the sample scored within the reference range. This means that they represent the typical general public rather than clinical or incarcerated populations. The researchers obtained functional magnetic resonance imaging scans of each participant along with study data.
Functional magnetic resonance imaging works by detecting changes in blood flow and oxygenation, which act as surrogates for actual neural activity. The scans analyzed in this study were captured during resting states, not during specific cognitive tests. Participants simply wake up in the scanner and gaze into a low-contrast crosshair to minimize visual stimulation. This protocol allowed the researchers to capture authentic spontaneous brain network activity during baseline conditions.
To process the large amount of image data, the researchers used a type of unsupervised machine learning. They fed their brain scans into an algorithm that blindly separated the signals into 20 different neurobiological networks. Because the algorithm was not given a predefined anatomical region to search, it provided a data-driven map of how the brain was functioning across the entire sample. This prevented the researchers from introducing subjective geographic bias into the analysis.
The team focused specifically on low-frequency spectral power within these isolated networks. This measurement serves as an indicator of intrinsic neural excitability, indicating how active a brain region remains by default when a person is physically at rest. Low frequency power is deeply associated with tonic arousal, which determines how individuals passively monitor their environment. The team mapped these network activity levels with participants’ scores on personality questionnaires to look for correlations.
Two specific brain networks effectively predicted overall Dark Triad scores in our sample. The first is the central executive network, a system that manages goal maintenance, focused attention, and flexible problem solving. People with high scores on dark personality traits showed increased baseline activity in this cognitive network.
Researchers suggest that this high baseline power reflects a chronically primed cognitive state. This heightened environmental vigilance and strategic cognitive control help people successfully navigate social situations. Deception requires sustained mental effort to maintain the lie and properly assess the target’s emotional response. In support of this theory, researchers found a specific positive correlation between elevated activity in the central executive network and high scores on a scale of Machiavellianism.
The second predictive circuit was the posterior segment of the default mode network. This network is traditionally active when the brain is at rest and governs self-referential thinking, memory processing, and social cognition. The default mode network handles the ability to understand the inner lives of others, a psychological skill known as theory of mind. Impaired functioning in this area is deeply correlated with deficits in moral reasoning.
In contrast to the central executive network, participants with high dark personality scores had decreased activity in the default mode network. Researchers have linked this weakened spontaneous activity to slowed self-reflection and reduced empathy, which are common features of both narcissism and psychopathy. Reduced activity in these specific areas can make it very difficult for individuals to form deep social connections. Impaired emotional control in narcissism can manifest as hypersensitivity to criticism, caused by a lack of self-reflection.
The exact regions showing reduced activity included the parieto-occipital region, a segment previously thought to be involved in clinical impulsivity. The reduction in baseline activity here corresponds closely to the impulsive and risk-taking behavior commonly seen in individuals high in psychopathic traits. Weak networks can impede an individual’s ability to engage in future-oriented thinking. This lack of foresight often results in rash decisions being made without considering the long-term consequences.
Taken together, these contradictory patterns suggest that the rise in dark personality traits depends on enhanced goal-directed vigilance combined with suppression of reflective activity. These people’s brains seem to be physically wired to prioritize tool manipulation over emotional connection. These results represent a network-level signature of dark personality traits and advance the idea that brain-wide dynamics parallel antagonistic behavior.
This study includes several limiting factors that prevent broader generalization. This research relies entirely on self-report surveys to measure personality traits, which may not fully capture the nuances of a person’s psychological profile. Even if surveys account for basic self-presentation biases, people with high deception scores may not be accurately reporting their own behavior. To validate these findings, subsequent studies will need to incorporate multiple different behavioral assessment tools.
Because this study extracted observational data for a single period, causality cannot be determined. It remains entirely unclear whether these brain patterns cause dark personality traits, or whether practicing antisocial traits slowly shapes the brain over the adult lifespan. The open access dataset also lacked detailed demographic information such as socioeconomic status and racial identity. Lacking such variables, the team was unable to investigate how environmental or cultural factors relate to personality development.
Future longitudinal studies will be needed to follow individuals over time and observe how these neural networks mature. Such studies could determine whether neural patterns are permanent biological traits or change with age and experience. Understanding the temporal dynamics of these brain correlates may ultimately help scientists develop interventions against extreme antisocial behavior. Modifying pathological personality traits with targeted therapies requires a firm understanding of how the adult brain changes.
The study, “Neural Fingerprints of the Dark Triad: Changes in Resting State BOLD Power (fALFF) in Executive Mode and Default Mode Networks,” was authored by Richard Bakiaj, Clara Isabel Pantoja Muñoz, and Alessandro Grecucci.
