In mid-March, as coronavirus cases started their sharp climb in the United States, many Americans appeared to have one thing in mind before hunkering down: Buy toilet paper. Lots of it.

But not everyone grabbed every roll in sight, and research published Friday in the journal Plos One offers insights into why some people scrambled for toilet paper while others held back.

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The study looked at whether different personality traits were associated with toilet paper hoarding, and found stockpilers tended to be more anxious and fearful about the coming health threat compared with those who didn’t load up on the product.

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Researchers from Germany surveyed 966 volunteers from 22 countries, including the U.S. The participants were asked to fill out a psychological questionnaire, to supply demographic information — and to provide details on their toilet paper purchases and consumption during the last week of March.

What most surprised the researchers was the similarity in responses no matter which country people came from, said study co-author Theo Toppe, a doctoral student and research associate at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

Toppe and his colleagues don’t know exactly why people hoarded — that question wasn’t asked on the survey. What they do know is which personality traits were most common amongst those who stockpiled.

When the researchers analyzed their data, they found that people were more likely to hoard if they were especially frightened by COVID-19. They also were likely to stockpile if they scored high in emotionality — that is, they tended to be more fearful, anxious, dependent and sentimental — and/or high in conscientiousness — folks who are organized, diligent, perfectionistic and prudent.

And while the study only focused on toilet paper purchases, stockpiling likely wasn’t limited to that, Toppe said in an email. “From our point of view, it seems plausible that our pattern of results — more threat goes along with more stockpiling — exists for other commodities,” he said.

Psychologist Neda Gould wasn’t surprised by the findings.

“This study tells us what we may have thought intuitively,” said Gould, a clinical psychologist and an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine.