People who score high in personality traits that are a part of the "Dark Tetrad" — narcissism, Machiavellianism, psychopathy and sadism — are more likely to interfere in the romantic lives of their family and friends when they dislike or disapprove of a relationship, a new study determined.

In a paper published March 25 in the Journal of Social and Personal Relationships, psychology researchers conducted surveys to identify the "dark," or negative, traits of disapproving friends and family who interfere in a disliked couple's romantic relationship. It was the first study on relationship interference that directly targeted factors related to commitment, and the first to examine whether those who meddle in others' love lives show certain dark personality traits.

Brian Collisson, an associate professor at Azusa Pacific University in California and lead author of the paper, explained to The Academic Times that the Dark Tetrad is an extension of the Dark Triad, a trio of personality traits known in psychology that includes narcissism, Machiavellianism and psychopathy. Adding sadism completes the tetrad of dark traits, which identify people who tend to seek immediate gratification, who are pragmatic and exploitative and who often use others as a "means to an end."

People who score high on Dark Tetrad traits typically have volatile relationships with their family and friends that are characterized by poor social support and low relationship satisfaction. Prior psychology research has determined that men score higher on dark personality traits than women, which suggests that they might be more likely to interfere with relationships. But social psychology research says that women are more communal, or concerned about others, than men, which would make them more likely to interfere in a relationship.

"This paper on meddling friends and family is a nice combination of some previous studies about social relationships [and] the dark personality traits, and what those traits look like when they play out within relationships amongst friends and amongst family members," Collisson said.

Narcissistic people tend to be self-centered, entitled, disinterested in warm relationships and socially adept. In this setting, friends and family members who score high in narcissism may overestimate their knowledge of what a disliked couple needs or whether they should remain together, according to the paper. People high in Machiavellianism tend to manipulate and deceive others for their own self-interest, or exploit a loved one in a relationship they dislike.

Psychopathy indicates a lack of remorse and empathy, and a tendency to be impulsive and aggressive. And people who score high in sadism tend to be cruel, brutal and enjoy inflicting harm on others, engaging in unprovoked aggression and other antisocial behavior.

The researchers conducted two experiments for the study. The first included 206 adults who reported having a platonic friend in a current relationship that they disliked or disapproved of, with 71% discussing a friend of the same gender. In the second experiment, a separate set of 180 adults were asked about a family member who was currently, or had been in the past, in a relationship they disliked or disapproved of, with 42% discussing a sibling.

Participants in both experiments took a series of surveys that asked how often, if at all, they interfered in their friend or family member's relationship based on factors relating to commitment, reporting answers that ranged from never to almost always.

The authors hypothesized that high scores on the Dark Tetrad would predict relationship interference. They expected that friends and family who disapprove of a loved one's relationship may target their interference on factors specifically related to commitment, such as relationship satisfaction, referring to how well a romantic partner is meeting emotional needs such as companionship, security and belonging; investment size, or the amount of resources attached to the relationship that would be lost if it ended, including time, children, shared friendships or shared property; and perceived quality of alternatives, meaning the desire to be single or in a different relationship with another partner.

"Previous studies have shown that the more interference couples experience, the less committed they tend to be to their partner," Collisson explained. "This study is really extending that and saying, when [people who score high on the Dark Tetrad] interfere, these are the specific things that they're doing or targeting to undermine a couple's commitment."

People interfering in relationships may use these strategies in ways such as providing their loved one with emotional support before their significant other has a chance, pointing out instances when their needs were unsatisfied, excluding the significant other from social events, suggesting academic or career goals be prioritized over the relationship or pointing out other potential romantic partners who are available.

"Others' judgments about a relationship is a significant predictor of people's choice of a romantic partner, their relationship quality and satisfaction, stability, investment, commitment and likelihood of breakup," the authors said in the paper. 

"When friends or family disapprove of a couple's romantic relationship, they may interfere with the intent of harming or dissolving the relationship. For instance, in a survey of college students, 56% of participants reported trying to harm or dissolve another person's romantic relationship," they continued.

To measure dark personality traits, the researchers used the Dirty Dozen Scale, a 12-item questionnaire that assesses narcissism, psychopathy and Machiavellianism. Participants rated the degree to which they agreed with statements such as, "I want others to pay attention to me," "I have used flattery to get my way," and "I tend to lack remorse."

Sadism was measured using the Revised Assessment of Sadistic Personality, a nine-item questionnaire in which participants rated the degree to which they agreed with statements such as, "I think about hurting people who irritate me" and "I get pleasure from mocking people in front of their friends."

"As expected, all of the Dark Tetrad traits were significantly positively correlated with the average relationship interference score, as well as each of the interference subscales," the authors said, in regard to both experiments.

"Dark personality in general, as well as sadism specifically, predicted relationship interference at all levels. Narcissism, Machiavellianism, and psychopathy did not independently predict any form of relationship interference," they continued.

The closer the participant reported being to their friend in experiment one, the more likely they were to admit to interfering in their relationship. Men were more likely than women to interfere in the first experiment, though the gender of their friend in the relationship did not make a statistically significant difference. 

"Sadism emerged as a strong predictor of relationship interference in Study 1. We suspect that sadistic people may enjoy negatively interfering in a friend's relationship because it harms the disliked romantic partner, and harm experienced by a loved one may be collateral damage," the authors said.

Experiment two resulted in similar overall findings, though women were more likely than men to report interfering in a family member's relationship. Narcissism emerged as a significant predictor of relationship interference in this experiment, which could be due to narcissistic family members thinking they know what is best for others and feeling entitled to negatively influence relationships of couples they dislike, according to the authors.

"It's also possible for friends and family members to interfere in a positive way, trying to help a relationship survive and overstepping boundaries, but with the intention of helping the relationship," Collisson said.

This study solely assessed dark traits. But Collisson plans to conduct further research to analyze more positive traits, including wisdom and loyalty, and whether they lead to positive interference in relationships.

The study, "Meddling friends and family: Dark Tetrad traits predict interference in disliked couples' romantic relationships," published March 25 in the Journal of Social and Personal Relationships, was authored by Brian Collisson and Jasmine Monleon, Azusa Pacific University; and Jennifer L. Howell, the University of California, Merced.