The road to trolldom is paved with frustration, according to a study published as part of the 2017 Conference on Computer-Supported Cooperative Work and Social Computing taking place later this month. A person is more likely to participate in abusive behavior or “trolling” based on their current mood and the context of the discussion they’re participating in.

Harassment and associated trolling have become the collateral damage of time spent socializing online. In 2014, Pew Research Center found that 70 percent of 18-to-24-year-olds online had been harassed. In a separate study that year, researchers found that people who troll demonstrated a strong link to personality traits of sadism, narcissism, psychopathy, and Machiavellianism. Research for the CSCW 2017 study was conducted by Stanford University and Cornell University with the aim of uncovering why disruptive internet behavior exists today in such larger numbers.

In the CSCW study, researchers experimented with 667 subjects who were first given one of two tests, either very easy or very difficult. After completing a questionnaire to gauge their mood, they were then invited to post comments on an article that already contained either neutral or negative comments. Grumpy commenters who also saw the negative posts engaged in trollish behavior about 68 percent of the time. Participants who’d taken the easier test and saw neutral comments, as opposed to the negative ones, only posted trolling comments 35 percent of the time. People subjected to either of those factors — a difficult test or negative comments — trolled 50 percent of the time.

That a bad mood would make someone more likely to behave badly online isn’t all that surprising. In 2014, Facebook found that positive or negative posts could affect the moods of users who saw them. Anecdotally, we’ve seen an internet troll’s personal environment affect online interactions. In 2015, writer Lindy West published a piece on The Guardian and did a segment on This American Life about confronting one of her trolls, who confessed to harassing her because he was unhappy with his own life.

Jure Leskovec, associate professor of computer science at Stanford and senior author of the CSCW 2017 study, described this behavior as “a spiral of negativity.”

“Just one person waking up cranky can create a spark and, because of discussion context and voting, these sparks can spiral out into cascades of bad behavior,” Leskovec said. “Bad conversations lead to bad conversations.”