Different psychopathic personality traits change how the brain allocates attention and processes emotions. A study published in the journal BMC Psychology shows that traits like boldness shift focus, while traits like meanness dampen emotional responses to distressing images. These different mechanisms provide a more nuanced perspective on the biological roots of psychotic behavior in the general population.
Psychopathy is not a single homogeneous condition. Psychologists often describe it as a set of distinct personality traits that appear to varying degrees in everyday people. The widely used triad model divides these traits into three main categories, including boldness, meanness, and disinhibition.
Boldness includes social superiority, emotional resilience, and lack of fear. Meanness is characterized by a lack of empathy, a tendency to exploit others, and ruthlessness. Disinhibition describes impulsive behavior, irritability, and difficulty controlling impulses.
Researchers have debated the underlying causes of these characteristics. One well-supported theory suggests that psychopathic behavior stems from a basic emotional flaw. Under this idea, the brain is unable to generate the normal emotions of fear and empathy because the sensory areas are not activated.
Another theory proposes an attentional bottleneck. This concept suggests that people with psychopathic traits are so focused on a goal or primary stimulus that they are unable to process secondary information. Overactivity in the prefrontal cortex can increase this focus and cause us to ignore threats and the pain of others in our environment.
This line of research is consistent with modern scientific frameworks that view mental health conditions as a spectrum rather than a strict category. The National Institute of Mental Health encourages research into how these traits manifest in general society. By examining milder versions of these traits, scientists hope to uncover the fundamental biological circuits that drive behaviors before they reach clinical or criminal thresholds.
To test these competing ideas, Tinhwan Son, a neuroscience researcher at the Erasmus Medical Center, organized a study with a team of Dutch and Australian collaborators. The research group wanted to see if specific brain responses could differentiate attention deficits from emotional deficits. They aimed to map these reactions to distinct characteristics: boldness, meanness, and disinhibition.
Soong and his team recruited 115 healthy adults for the experiment. Participants had no criminal history or clinical psychiatric diagnoses. By assessing community samples, researchers were able to study how psychopathic traits function along a normal spectrum.
Participants first completed a self-report survey measuring their levels of boldness, sneakiness, and disinhibition. They also completed a questionnaire to assess their general capacity for cognitive, emotional, and physical empathy.
The researchers then had participants view a series of positive, negative, and neutral images on a smartphone mounted on a stand in front of them. Negative images included tragic scenes, such as injured victims, while positive images included cute animals.
While viewing these images, participants occasionally heard loud white noise coming from their headphones. This noise acts as a startle probe. In humans, hearing a sudden loud noise triggers an involuntary, defensive blink controlled by basic survival circuits in the brain.
To continuously measure this reflex, the researchers used a smartphone application called BlinkLab. The software tracked facial landmarks through the phone’s front-facing camera and calculated the exact intensity of each participant’s startle blink.
At the same time, participants wore caps lined with electrodes to record electrical activity in their brains. The researchers monitored specific brain wave patterns known as event-related potentials. One pattern indicates involuntary shifts in attention, and another reflects long-term emotional processing.
By presenting loud noise at different intervals after the image appeared, the scientists were able to track how attention and emotions changed in real time. Noise occurred 50, 700, and 4500 ms after the image appeared on the screen.
The results showed that when psychopathic traits are isolated, they are linked to very different brain responses. The researchers found support for both affective deficit theory and attentional bottleneck theory, depending on the specific characteristics being assessed.
For example, boldness was associated with stronger attentional bottlenecks, especially in male participants. When men with high boldness scores viewed negative images, their brains showed exaggerated spikes in attention-related brain waves at 700 milliseconds.
During this fraction of a second, the brain is typically busy processing the visual scene. Because of their higher concentration, these people were less likely to focus their mental resources on sudden loud sounds.
This finding suggests that bold individuals do not necessarily lack the biological hardware to process threats. Instead, their attention becomes hyper-focused on what’s in front of them. This limits your ability to record other things happening in your environment.
In contrast, meanness is closely related to emotional deficit theory. Participants with higher meanness scores reported lower levels of both emotional and physical empathy in the first survey. During the experiment, when viewing the negative image, a silent startle blink was observed, especially at the 4500 millisecond mark.
Typically, viewing a distressing image for a few seconds puts a person’s nervous system on alert. This usually makes the protective flashing very severe in case of sudden noise. The absence of this heightened reflex in mean people suggests a blunted physiological response to dire situations.
It was also shown that when participants scored high on both boldness and sneakiness, they had weaker brainwave responses associated with processing complex emotions. This suggests that the two traits may combine to further suppress empathic responses.
The third trait, disinhibition, showed no relationship with the biological markers of emotion or attention measured in this experiment. The researchers suggest that disinhibition may be caused by various neural mechanisms related to impulse control, rather than fundamental changes in fear processing or visual attention.
This study relies on a relatively specialized experimental setup and therefore has certain limitations. The image database used to elicit emotions contained distressing visual content, but did not include extreme, direct threat scenarios. The use of highly threatening images may have resulted in greater variability in the startle reflex.
The researchers also noted that repeated use of loud noises may create an anticipatory effect in participants. After a few trials, subjects may have begun to expect the startle probe. This expectation can change how the brain allocates attention at later time intervals.
Future projects will require expanding the scope of the test environment. The researchers recommend testing these concepts in larger groups to better understand potential differences between men and women. They also plan to see if these patterns hold true in clinical populations, such as people diagnosed with severe personality disorders.
Understanding the biological roots of these traits may ultimately help psychologists design more appropriate early interventions. If a person’s antisocial behavior is due to an attention bottleneck, treatment may focus on cognitive therapy to expand the person’s awareness. If the behavior is due to an emotional deficit, treatments may target emotional pathways instead.
The study, “Emotional and Attention Abnormalities Underlying Triadic Psychopathy: An EEG Startle Blink Study,” was authored by Ting-Fang Soong, Jordi PA Booij, Katharina Stapel, Carolien Bunnik, Iris Zwilling, Antonia Karp, Sebastian KE Koekkoek, Kayleigh Koekkoek, Gulti Rogge, EM Logge, and Deen. Cornelis P. Boele, Chris I. de Zeeuw, Henk-Jan Boele, Josanne DM van Dongen.
