A new study published in Biological Psychology has found that people with higher levels of psychopathic meanness show weaker brain responses when viewing emotional facial expressions—including fear, anger, happiness, and neutral faces. This dampened reactivity was not seen in relation to other psychopathic traits like boldness or disinhibition. The study highlights a general deficit in how individuals high in meanness process faces at a very early stage of perception, within 200 milliseconds after seeing a face.
The researchers conducted this study to better understand the unique emotional and social processing problems associated with meanness, one of the three personality traits in the triarchic model of psychopathy. This model describes psychopathy as a combination of boldness, disinhibition, and meanness.
While previous studies have shown that meanness is related to problems recognizing fear in others, it remained unclear whether these difficulties also apply to other emotions. The study also sought to determine whether other traits—like boldness, which reflects fearless dominance, or disinhibition, which reflects impulsivity—play a similar role in facial emotion processing.
The triarchic model breaks psychopathy down into three key dimensions. Boldness is associated with charm, confidence, and low fear in risky situations. Disinhibition is tied to poor impulse control, recklessness, and a tendency to ignore social norms. Meanness is defined by callousness, lack of empathy, shallow emotions, and a general disregard for close relationships.
Previous work has connected meanness to reduced attention to emotional cues and poor recognition of others’ emotions. These issues may contribute to the cold, aggressive, and antisocial behaviors often seen in individuals with high levels of meanness. However, most past research has focused only on fear and has not accounted for the potential influence of other psychopathic traits.
“Deficits in emotional processing are a hallmark of psychopathic personality. Prior research has suggested that impaired recognition of distress emotions in others — particularly, fear and sadness — might be a key mechanism underlying the low empathy and callousness features of psychopathic individuals,” said study author Victoria Branchadell, a postdoctoral researcher at the Autonomous University of Madrid.
“However, there is still debate in the field of whether this deficit is specific to distress cues or reflects a broader impairment in recognizing other emotional expressions as well (e.g., happy or angry expressions). In this study, we measured event-related brain potentials derived from EEG recordings to investigate alterations in early perceptual stages of face processing associated with individual differences in the meanness dimension of psychopathy. Our goal was to determine whether these deficits are generalized across different emotional face stimuli or specific to certain emotional expressions.”
For their study, which was conducted at Jaume I University, the research team recruited 119 undergraduate students from Spain. Participants completed a questionnaire measuring the three triarchic traits. During the experiment, they sat in a quiet, dimly lit room while their brain activity was recorded using high-density electroencephalography (EEG). The participants passively viewed images of human faces expressing fear, anger, happiness, or neutrality, along with scrambled images that contained no facial structure.
While participants looked at the images, the researchers focused on a brain response known as the N170 component. This electrical signal appears about 170 milliseconds after a face is seen and is considered a reliable indicator of the brain’s early face-processing system. The N170 is typically larger when people view faces compared to other objects and can vary depending on the emotional expression shown.
The analysis revealed that individuals with higher meanness scores had significantly smaller N170 responses when viewing all types of facial expressions. This pattern held true for angry, fearful, happy, and neutral faces but was not observed for the scrambled images, suggesting that the reduced brain activity was specific to facial processing rather than a general blunting of visual reactivity.
“We were surprised to find that this deficit seems to be pervasive across different emotional expressions,” Branchadell told PsyPost. “Indeed, the literature seems indicate more robust impairments in recognizing fear and sadness expressions. However, we have only examined here early brain correlates of face perception, and not how these might relate to the accuracy of recognition of the facial expressions we examined, so future research should clarify how alterations in basic perceptual mechanism relate to impairments in recognition for different emotions.”
Importantly, this relationship remained significant even after accounting for the influence of boldness and disinhibition. In contrast, neither boldness nor disinhibition was linked to changes in the N170 response.
The researchers also found that, overall, male participants showed stronger N170 responses to faces than female participants, and males also scored higher on meanness. However, when controlling for sex, the link between meanness and reduced N170 amplitudes remained consistent. This suggests that the relationship is not simply due to sex differences in brain activity or psychopathy levels.
“The main conclusion of the study is that the meanness traits of psychopathy — reflecting callousness and low empathy features — are associated with reduced brain reactivity to facial stimuli, regardless of the expression presented (angry, fearful, happy, neutral),” Branchadell explained. “This blunted neural processing of faces can be detected very early in time (prior to 200 ms after face stimuli onset) which suggests difficulties in the process of rapidly extracting and ‘putting together’ individual features of face stimuli.”
“Another takeaway is that this deficit seems specific to the callousness features of psychopathy, but not to the impulsive/unrestrained or the venturesomeness and socially dominant features of this disorder, which highlights the relevance of considering psychopathy as multifaceted.”
One strength of the study is its use of a wide range of facial expressions and naturalistic face images, which improves the ecological validity of the findings. Many earlier studies focused only on fearful faces or used altered images, which may not fully capture how people respond to faces in real-life situations.
Despite its strengths, there are some limitations to consider. The sample consisted primarily of female undergraduate students, which may limit the generalizability of the findings. Also, the task involved passively viewing images rather than actively recognizing emotions, so it remains unclear how the observed brain differences relate to behavior in real-world social situations.
“While a passive viewing task provides a controlled experimental context for assessing individual differences in baseline reactivity to face stimuli, it did not allow to evaluate whether the observed reduced reactivity to facial expressions also extends to the behavioral level,” Branchadell said.
Looking ahead, the researchers hope to explore whether these early neural differences could serve as potential markers for identifying people at risk for social and emotional difficulties linked to psychopathy. By better understanding how the brain responds to social cues in individuals high in meanness, scientists may eventually be able to develop more targeted interventions or tools for early identification.
“The main purpose of our psychophysiological and behavioral studies on different aspects of emotional processing in relation to meanness is to better characterize and understand the deficits associated with this dimension of psychopathy,” Branchadell explained. “In the future, we would like to formally test whether such psychophysiological and behavioral measures might be viable candidates to be incorporated in neuroclinical assessments that can foster our understanding of the biological systems and processes underlying this personality disorder.”
The study, “Meanness and deficits in facial affect processing: evidence from the N170,” was authored by Victoria Branchadell, Pilar Segarra, Rosario Poy, Javier Moltó, and Pablo Ribes-Guardiola.