Most of the time, we try to avoid inflicting pain on others — when we do hurt someone, we typically experience guilt, remorse, or other feelings of distress. But for some, cruelty can be pleasurable, even exciting. New research suggests that this kind of everyday sadism is real and more common than we might think.

Two studies led by psychological scientist Erin Buckels of the University of British Columbia revealed that people who score high on a measure of sadism seem to derive pleasure from behaviors that hurt others, and are even willing to expend extra effort to make someone else suffer.

The new findings are published in Psychological Science, a journal of the Association for Psychological Science.

“Some find it hard to reconcile sadism with the concept of ‘normal’ psychological functioning, but our findings show that sadistic tendencies among otherwise well-adjusted people must be acknowledged,” says Buckels. “These people aren’t necessarily serial killers or sexual deviants but they gain some emotional benefit in causing or simply observing others’ suffering.”

Based on their previous work on the “Dark Triad” of personality, Buckels and colleagues Delroy Paulhus of the University of British Columbia and Daniel Jones of the University of Texas El Paso surmised that sadism is a distinct aspect of personality that joins with three others — psychopathy, narcissism, and Machiavellianism — to form a “Dark Tetrad” of personality traits.

To test their hypothesis, they decided to examine everyday sadism under controlled laboratory conditions. They recruited 71 participants to take part in a study on “personality and tolerance for challenging jobs.” Participants were asked to choose among several unpleasant tasks: killing bugs, helping the experimenter kill bugs, cleaning dirty toilets, or enduring pain from ice water.

Participants who chose bug killing were shown the bug-crunching machine: a modified coffee grinder that produced a distinct crunching sound so as to maximize the gruesomeness of the task. Nearby were cups containing live pill bugs, each cup labeled with the bug’s name: Muffin, Ike, and Tootsie.

The participant’s job was to drop the bugs into the machine, force down the cover, and “grind them up.” The participants didn’t know that a barrier actually prevented the bugs from being ground up and that no bugs were harmed in the experiment.

Of the 71 participants, 12.7% chose the pain-tolerance task, 33.8% chose the toilet-cleaning task, 26.8% chose to help kill bugs, and 26.8% chose to kill bugs.

Participants who chose bug killing had the highest scores on a scale measuring sadistic impulses, just as the researchers predicted. The more sadistic the participant was, the more likely he or she was to choose bug killing over the other options, even when their scores on Dark Triad measures, fear of bugs, and sensitivity to disgust were taken into account.

Participants with high levels of sadism who chose to kill bugs reported taking significantly greater pleasure in the task than those who chose another task, and their pleasure seemed to correlate with the number of bugs they killed, suggesting that sadistic behavior may hold some sort of reward value for those participants.

And a second study revealed that, of the participants who rated high on one of the “dark” personality traits, only sadists chose to intensify blasts of white noise directed at an innocent opponent when they realized the opponent wouldn’t fight back. They were also the only ones willing to expend additional time and energy to be able to blast the innocent opponent with the noise.

Together, these results suggest that sadists possess an intrinsic motivation to inflict suffering on innocent others, even at a personal cost — a motivation that is absent from the other dark personality traits.

The researchers hope that these new findings will help to broaden people’s view of sadism as an aspect of personality that manifests in everyday life, helping to dispel the notion that sadism is limited to sexual deviants and criminals.

Buckels and colleagues are continuing to investigate everyday sadism, including its role in online trolling behavior.

“Trolling culture is unique in that it explicitly celebrates sadistic pleasure, or ‘lulz,’” says Buckels. “It is, perhaps, not surprising then that sadists gravitate toward those activities.”

And they’re also exploring vicarious forms of sadism, such as enjoying cruelty in movies, video games, and sports.

The researchers believe their findings have the potential to inform research and policy on domestic abuse, bullying, animal abuse, and cases of military and police brutality.

“It is such situations that sadistic individuals may exploit for personal pleasure,” says Buckels. “Denying the dark side of personality will not help when managing people in these contexts.”