Adults bully for a tangle of reasons, not a single one, but the research points to a few core drivers: certain personality traits (especially those in the so-called Dark Triad), distorted thinking patterns that let people justify cruelty, hormonal and neurological differences that make aggression feel rewarding, and environments that tolerate or even encourage domination. The picture is messier than the schoolyard version of bullying, partly because adult bullying often hides behind professional language, social media anonymity, or organizational hierarchies. Understanding why it happens requires pulling apart personality, cognition, biology, and context and seeing how they reinforce one another.
The Dark Triad and Bullying Perpetration
If you want to predict who is likely to bully others, personality research keeps circling back to three traits: narcissism, psychopathy, and Machiavellianism. Collectively called the Dark Triad, these traits describe people who tend to be self-centered, emotionally cold, and strategically manipulative. A recent systematic review and meta-analysis of workplace bullying found that all three traits are positively linked to bullying perpetration, and the combined Dark Triad score showed a strong pooled correlation with bullying behavior. Among the individual traits, psychopathy had the largest association, while narcissism and Machiavellianism showed moderate effects.1PubMed Central. Dark Triad traits and workplace bullying: a systematic review and meta-analysis of personality, power, and psychosocial safety
That pattern, with psychopathy on top, has been consistent across studies. An earlier investigation looking specifically at adult bullying behaviors found the same rank order: psychopathy showed the strongest correlations with bullying subscales, and narcissism the weakest.2Personality and Individual Differences. Relationships between bullying behaviours and the Dark Triad: A study with adults What this means practically is that the adults most likely to bully others aren’t just rude or short-tempered. They tend to lack empathy, treat relationships as transactional, and feel entitled to special treatment. Psychopathy’s outsized role makes sense: the core of psychopathy is a reduced capacity for guilt and emotional connection, which removes the internal brakes most people have against hurting someone repeatedly.
This doesn’t mean every narcissistic or manipulative person becomes a bully. Plenty of people score moderately on these traits without ever targeting someone. But when these traits are elevated and combined with the right situational triggers, they form a reliable recipe for sustained aggression toward others.
Threatened Egos and the Drive for Status
Narcissism’s link to bullying deserves its own closer look, because it works through a specific mechanism: ego threat. A systematic review of narcissism and aggression found strong evidence, particularly from student samples, that narcissistic individuals become aggressive when their inflated self-image is challenged.3PubMed. The Role of Narcissism in Aggression and Violence: A Systematic Review The aggression isn’t random. It’s reactive, triggered when someone contradicts, outperforms, or publicly embarrasses them. In a workplace, this can look like a manager who retaliates against an employee who questioned their decision, or a colleague who starts a whisper campaign after being passed over for a promotion that went to someone they consider inferior.
A related but distinct driver is what researchers call social dominance orientation, the belief that social hierarchies are natural and that some people deserve to be on top. Research has found moderate positive relationships between social dominance orientation and multiple forms of bullying, including verbal aggression, social manipulation, and attacks on property.4Communication Research Reports. Bullying as a Display of Social Dominance Orientation People high in social dominance orientation don’t just tolerate hierarchy; they actively enforce it. Bullying becomes a tool for establishing and maintaining their position. This helps explain why adult bullying so often flows downward in organizations: from managers to subordinates, from senior members to newcomers, from socially established individuals to outsiders.
How Bullies Think Their Way Past Guilt
Even people with dark personality traits usually need to tell themselves a story that makes their behavior acceptable. The psychological machinery for this is called moral disengagement, a set of cognitive strategies that let someone act harmfully while avoiding self-condemnation. Among the most effective strategies linked to bullying are moral justification (“They deserved it”) and displacement of responsibility (“I was just doing what anyone would do in that situation”).5PubMed Central. From victim to bully: unpacking moral disengagement and the buffering effect of legal cognition Other common tactics include minimizing consequences (“It wasn’t that bad”), euphemistic labeling (“I was just joking around”), and dehumanizing the target (“They’re not like the rest of us”).
These aren’t conscious, deliberate calculations for most bullies. They’re automatic cognitive habits that develop over time. Someone who regularly bullies others genuinely may not see themselves as a bully, because their internal narrative has reframed every incident.
Alongside moral disengagement, a second cognitive distortion feeds adult aggression: hostile attribution bias, the tendency to interpret ambiguous social cues as threatening or intentionally hostile. Research on adults has found that hostile attribution bias is positively associated with all four major forms of aggression, including physical, verbal, relational, and indirect.6PubMed Central. Hostile attributional bias, negative emotional responding, and aggression in adults: moderating effects of gender and impulsivity If you habitually assume that a coworker’s neutral comment was a veiled insult, or that a friend’s delayed text reply was a deliberate snub, you’ll feel justified in striking back. The aggression feels defensive even when, from the outside, it looks unprovoked.
What the Brain and Hormones Reveal
The psychology of bullying has a biological underbelly. Neuroimaging research on adolescents who bully has found that when they watch scenes of social exclusion, their brains light up differently than non-bullies’. Specifically, self-reported bullying was associated with greater activation in the ventral striatum, amygdala, medial prefrontal cortex, and insula while viewing exclusion scenes.7PubMed Central. Links between adolescent bullying and neural activation to viewing social exclusion Those regions are tied to reward processing, salience monitoring, and motivation. The implication is unsettling: for some individuals, watching someone else get excluded may activate the brain’s reward circuitry. Social dominance, in other words, can feel good at a neural level.
On the hormonal side, a growing body of work points to the ratio between testosterone and cortisol as a predictor of aggressive behavior. The idea, sometimes called the dual-hormone hypothesis, is that testosterone pushes toward status-seeking and dominance, while cortisol (the stress hormone) acts as a brake on risky or aggressive behavior. When testosterone is high and cortisol is low, the brake is weak. A systematic review of this relationship in younger populations found that high testosterone combined with low cortisol was linked to increased aggression, especially in adolescence.8Aggression and Violent Behavior. A systematic review of the relationship between cortisol, testosterone, and aggression in children and adolescents In adults, research on intimate-partner aggression has similarly found that a higher testosterone-to-cortisol ratio predicted greater aggression, and this held regardless of sex.9PubMed. Testosterone to cortisol ratio and aggression toward one’s partner: Evidence for moderation by provocation
There is a gender wrinkle, though. A study of over 500 undergraduates found that strain combined with a higher testosterone-to-cortisol ratio predicted antisocial behavior in males but not females.10Crime & Delinquency. Examining How Testosterone and Cortisol Influence the Relationship Between Strain, Negative Emotions, and Antisocial Behavior: A Gendered Analysis This doesn’t mean women don’t bully; they do, often through relational and indirect forms of aggression. One Canadian study actually found that men reported using indirect aggression more frequently than women, which challenges the popular assumption that indirect aggression is a “female” strategy.11Evolutionary Psychology. Sex Differences in the Use of Indirect Aggression in Adult Canadians The biology of aggression sets a stage, but the form bullying takes is shaped by social learning, opportunity, and what a given culture permits.
Roots in Childhood Experience
Adult bullies often have histories that extend back to childhood, and one of the most telling patterns involves the “bully-victim,” someone who was both a target and a perpetrator. A large prospective study tracking children into adulthood found that bully-victims faced elevated risks of poor health, financial difficulty, and troubled social relationships later in life, even after accounting for family hardship and childhood psychiatric disorders.12PubMed Central. Impact of bullying in childhood on adult health, wealth, crime, and social outcomes This group had worse outcomes than either “pure” bullies or “pure” victims, suggesting that the combination of being hurt and hurting others creates a particularly damaging developmental trajectory. Many adult bullies carry forward aggressive interpersonal scripts learned early, especially when no intervention disrupted the pattern.
Attachment style offers another window into how early relationships shape adult aggression. An exploratory study of workplace bullying found that an avoidant attachment style had a significant positive effect on bullying perpetration, while anxious attachment did not reach significance.13Nurture. Insecure Attachment Styles and Bullying Perpetrators in the Workplace: An Exploratory Study Avoidant attachment, which typically develops when caregivers are emotionally unavailable or dismissive, fosters a view of relationships as competitive and others as untrustworthy. People with this style may rely on dominance and control rather than closeness to navigate social settings, making bullying a natural, if destructive, interpersonal strategy.
Environments That Enable Bullying
Personal psychology explains who is predisposed to bully, but the environment determines whether that predisposition gets expressed. You can have a roomful of people with elevated Dark Triad traits, and whether bullying breaks out depends heavily on the culture they’re operating in.
Leadership matters enormously. Research on toxic leadership in healthcare settings found that toxic leaders had a substantial positive influence on workplace deviance, and that emotional exhaustion among employees amplified this effect.14PubMed Central. The effect of toxic leadership on workplace deviance: the mediating effect of emotional exhaustion, and the moderating effect of organizational cynicism When a manager models aggression, plays favorites, or punishes dissent, it signals to everyone that domination is an acceptable way to operate. Employees who might otherwise suppress aggressive impulses start to act them out, particularly when they’re already burned out and exhausted.
Cultural dimensions also shape how bullying manifests across societies. Research has pointed to three cultural factors as particularly relevant: assertiveness norms (how much a culture values forceful communication), in-group collectivism (how tightly social groups close ranks), and power distance (how much inequality between people is considered normal).15International Journal of Cross Cultural Management. Workplace bullying across cultures In high power-distance cultures, for instance, bullying by supervisors may be accepted as a natural part of hierarchy rather than recognized as a problem. In highly collectivist settings, bullying can take the form of group ostracism against someone perceived as an outsider. The behavior adapts to whatever social structures are available.
Why Bystanders Matter More Than You Think
Adult bullying rarely happens in a vacuum. It typically unfolds in front of others, and how those bystanders respond has a powerful effect on whether the bullying continues or escalates. Research consistently shows that bystander behavior is not passive; it’s driven by specific psychological judgments about the victim.
One of the strongest predictors is perceived responsibility. When bystanders believe the victim is somehow responsible for their own targeting, they feel anger rather than sympathy, and they’re more likely to engage in antisocial behavior toward the victim or simply withdraw help.16Journal of Community & Applied Social Psychology. Predictors of Antisocial and Prosocial Behaviour of Bystanders in Workplace Mobbing When victims are seen as blameless, bystanders feel sympathy and are more inclined to intervene. This creates a perverse dynamic: bullies who are skilled at framing the victim as the problem can effectively recruit passive bystander support.
Fear plays a role too. Bystanders who anticipate stigma by association, meaning they worry that helping the victim will make them a target as well, report more fear and less willingness to step in. This effect shows some gender differences: in one experiment, both women and men reported more fear under high stigma-by-association conditions, but the downstream effects on helping behavior played out differently for each group.17PubMed. Workplace mobbing and bystanders’ helping behaviour towards victims: the role of gender, perceived responsibility and anticipated stigma by association The victim’s own response style also matters: victims who show approach coping (confronting the situation directly) are seen as more self-reliant and less responsible for the continuation of the bullying, which increases bystander willingness to help.18PubMed. Workplace mobbing: How the victim’s coping behavior influences bystander responses
Bullying Behind a Screen
Online environments strip away many of the social cues that ordinarily restrain aggression. You can’t see your target’s face crumple, and you may not even know their real name. This dynamic, often described as toxic disinhibition, meaningfully changes the psychology of bullying. A study of adults aged 19 to 66 found that psychological distress predicted cyberbullying perpetration, and that this link was stronger at medium and high levels of toxic disinhibition.19PubMed. Toxic sensation seeking? Psychological distress, cyberbullying, and the moderating effect of online disinhibition among adults In other words, feeling bad doesn’t automatically make someone a cyberbully, but feeling bad while also being the kind of person who loses their filter online substantially raises the risk.
Online bullying also generates its own cycles of retaliation. A survey-based study found that being a victim of online trolling was positively associated with engaging in reactive trolling, and that this path ran through revenge motivation. The effect was amplified by online disinhibition: people who felt less constrained by online social norms were more likely to retaliate aggressively after being targeted.20Social Science Computer Review. From Trolling Victimization to Reactive Trolling: Moderated Mediation Effects of Online Disinhibition and Motivations This means the internet doesn’t just give existing bullies a new platform. It creates new bullies, people who wouldn’t act aggressively in face-to-face interactions but who escalate online after being provoked in an environment that rewards retaliation and removes consequences.
An Evolutionary Angle
Some researchers have argued that bullying persists in adults partly because it works, at least in narrow evolutionary terms. A study examining bullying through the lens of social power found that bullying was positively associated with social dominance and dating popularity, but these benefits depended on the bully’s ability to also use manipulative affiliation, essentially, knowing when to be aggressive and when to be charming.21PubMed. An Evolutionary Perspective on Bullying and Social Power: The Roles of Cooperation and Manipulation The bullies who gained the most social power weren’t indiscriminately hostile. They alternated between coercion and strategic niceness, using aggression to push down rivals and charm to build alliances.
This helps explain something frustrating about adult bullies: they’re often well-liked by people who aren’t their targets. A manager who terrorizes one subordinate may be warm and generous to the rest of the team. A social group member who systematically excludes one person may be funny and inclusive toward everyone else. This flexibility is the point. It makes the bullying harder to name, harder to report, and harder to stop, because people outside the target zone genuinely don’t see the problem.
What Interventions Actually Achieve
Given how deeply rooted the drivers of adult bullying are, in personality, cognition, neurobiology, and environment, it’s worth asking whether interventions actually work. The honest answer is: somewhat, but not as much as you’d hope.
A Cochrane systematic review of workplace bullying interventions found that one of the more studied programs, Civility, Respect, and Engagement in the Workforce (CREW), produced a small increase in civility, roughly a 5% improvement from baseline, measured at six to twelve months. The program also showed a small decrease in supervisor incivility. But it did not significantly reduce co-worker incivility or self-reported bullying perpetration.22PubMed Central. Interventions for prevention of bullying in the workplace One bright spot: the program did reduce absenteeism, suggesting that even if the bullying itself doesn’t fully stop, the workplace climate improves enough for people to keep showing up.
A broader review of workplace bullying interventions found a pattern that should temper expectations: programs were more likely to change people’s knowledge, attitudes, and self-perceptions about bullying than to change actual bullying behavior. Effectiveness tended to increase at higher levels of intervention, meaning individual-level training did less than organization-wide policy changes. But the methodological quality of most studies was poor, making it hard to attribute improvements directly to the programs.23PubMed Central. Insights into workplace bullying: psychosocial drivers and effective interventions
The takeaway for anyone dealing with a bullying situation is that top-down structural changes, clear policies with enforcement, leadership accountability, and organizational culture shifts, are more promising than asking individuals to simply behave better. You can teach someone about moral disengagement and hostile attribution bias, and they might even recognize the patterns in themselves. But if the environment continues to reward dominance and ignore targets’ complaints, the cognitive habits that sustain bullying will keep finding justification.