New research reveals that specific psychological traits vary across different types of within-family murders. Emotional deficits play a pronounced role in distinguishing those who kill their parents or children from those who kill their siblings. The findings were recently published in the journal Deviant Behavior.
Homicide within a family happens frequently, accounting for a distinct portion of global crime. Despite the severity of these acts, researchers have rarely compared the psychological profiles of people who commit different variants of family murder. Understanding these psychological boundaries can help forensic professionals comprehend the roots of extreme domestic violence.
Researchers Jiseun Sohn of Southern University and A&M College, Adrian Raine of the University of Pennsylvania, and Young-Oh Hong of the Korean Institute of Criminology and Justice set out to fill this gap. They focused on psychopathy, a psychological condition characterized by specific personality and behavioral traits. These traits often predict general violence.
Psychopathy is commonly measured using an evaluation tool known as the Psychopathy Checklist-Revised. This test breaks the psychological condition down into four distinct categories, or facets. Trained evaluators use these categories to score offenders based on their personal histories and observed behaviors.
The first facet measures interpersonal problems, such as a tendency to manipulate others, engage in relentless deception, or exhibit pathological narcissism. People scoring high in this area often charm their relatives while secretly pursuing self-serving agendas. They generally view relationships as social games to win rather than partnerships to build.
The second facet evaluates affective deficits, which include a lack of empathy, an absence of guilt, and generally shallow emotions. Individuals with these traits struggle to form genuine emotional bonds. They may view their family members as obstacles or objects rather than loved ones.
The third category addresses an unstable or impulsive lifestyle. It captures traits like irresponsibility, parasitic living conditions, and a constant need for stimulation. A parent with high scores in this category might neglect their children in favor of impulsive thrills.
The final category looks at antisocial behaviors extending from childhood into adulthood. This includes poor behavioral controls, early delinquency, and a history of violating the rules of society. Within a household, these traits often present as domestic abuse or physical aggressiveness.
Prior studies have well documented the general link between psychopathy and homicide. Less is known about how these four psychological categories apply to family-specific murders. Some past reviews suggest that family violence may stem from prolonged emotional disputes, while others point to cold, calculated actions entirely devoid of empathy.
Sohn and colleagues recognized that lumping all family homicides together might obscure the distinct motivations behind them. Killing a spouse, for instance, might involve different psychological drivers than killing a parent or a sibling.
To investigate these differences, the researchers analyzed data from a sample of 213 offenders convicted of family homicide in South Korea between 2016 and 2018. The sample included individuals who committed four distinct types of murder. The largest group consisted of 143 individuals who committed intimate partner homicide, which involves killing a current or former spouse or romantic partner.
The other groups relied on small samples of offenders. These included 35 cases of parricide, or the killing of a parent, grandparent, or parent-in-law. Another small sample of 22 individuals committed filicide, which is defined as killing a child, grandchild, or child-in-law.
The final and smallest group consisted of 13 offenders convicted of siblicide, meaning they killed a sibling or step-sibling. Trained evaluators had previously assessed all of these individuals using the Psychopathy Checklist-Revised during standard prison intake interviews. The researchers analyzed this pre-existing data to see which of the four psychopathy categories best predicted the type of family murder committed.
The analysis revealed that the second category, which measures affective deficits, was the strongest indicator of differences among the groups. People who killed their parents exhibited the highest scores for affective deficits. They demonstrated a more pronounced lack of remorse and more shallow emotional responses than the other groups.
Offenders who committed parricide, filicide, and intimate partner homicide all scored higher on affective deficits than those who killed their siblings. The individuals convicted of siblicide had the lowest overall psychopathy scores across all four categories.
This suggests that the murder of a sibling might stem from alternative causes. Intense rivalries over money, inheritance disputes, or basic power struggles could act as the primary catalysts for this specific type of violence. Situational anger or extreme selfishness could spark the fatal incident rather than severe, lifelong personality disorders.
Offenders who committed filicide also demonstrated high levels of affective deficits. Parents who kill their children are sometimes found to suffer from severe psychiatric illnesses like depression or schizophrenia in the broader medical literature.
In the context of psychopathy, an extreme absence of emotional warmth and an inability to accept responsibility frequently accompany the neglect or abuse that ends in tragic outcomes. When empathy is fundamentally broken, a child becomes exceptionally vulnerable to violence.
The researchers also noticed distinctions between those who killed partners and those who killed parents. Intimate partner homicide offenders scored higher on interpersonal problems and antisocial behaviors than parricide offenders. The tendency to seek strict control over a partner or engage in superficial relationships aligned with these elevated scores.
Perpetrators in this group often view romantic partnerships as a social mechanism for achieving personal goals. When that control is threatened, their antisocial tendencies may manifest as lethal violence.
When comparing parricide to filicide, or intimate partner homicide to filicide, the differences in psychopathy scores were not statistically significant. The affective deficits category still stood out as the foremost psychological boundary separating the broader types of family murder from one another. By isolating these specific personality traits, the study offers a more precise look at how emotional detachment functions in extreme violence.
Evaluating these specific personality limitations proved more predictive of domestic violence subtypes than basic demographic factors. Details like age, gender, education, and income were included in the researchers’ initial analyses. These demographic details did little to differentiate the four types of family murderers.
Identifying a perpetrator’s specific psychological shortcomings could eventually aid forensic professionals in threat assessment. If behavioral specialists know that extreme emotional detachment strongly associates with violence against parents, they might better evaluate the risks within deeply troubled households. Interventions could be tailored to address specific relational dynamics based on personality traits rather than broad generalities.
The authors acknowledged several limitations in their approach to the data collection. The data gathering process was entirely retrospective, meaning the psychological evaluations took place after the offenders had already committed murder and entered the prison system.
Conducting an assessment after a traumatic violence event might influence how an individual responds to interview questions. It is impossible to know with complete certainty how their psychopathy traits manifested in the daily years leading up to the crime.
The research sample exclusively included homicide offenders. There was no comparison group of violent offenders who did not commit murder, making it hard to isolate traits that specifically trigger lethal outcomes versus general domestic abuse. Additionally, some of the specific homicide subsets represented very small samples.
The psychological patterns observed in a limited group of offenders might look different when assessed in broader, more diverse populations. Because the research took an exploratory approach, the findings provide a starting point rather than final conclusions. The investigators propose that future projects should adopt a hypothesis-driven structure to test these psychological profiles across different cultures.
The study, “The Role of Psychopathic Traits in Subtypes of Family Homicide,” was authored by Jiseun Sohn, Adrian Raine, and Young-Oh Hong.