When New Zealand's first case of COVID-19 was detected in late February, Kiwis rushed to the supermarket to buy toilet paper.
It was a curious response considering diarrhea isn't a particularly common symptom of the disease, and there were no signs then the country was going to be locked down or that supermarkets were going to shut.
The run on bog roll wasn't limited to New Zealand however, with Australians and Americans literally fighting in the aisles for some precious 2-ply.
While many of us shook our heads in bemusement, scientists in Europe decided to find out what kind of person thinks buying a year's supply of toilet paper at once is a good idea.
They surveyed more than 1000 people from 35 countries, and the biggest factor they could find was how scared they were of COVID-19.
"People who feel more threatened by the pandemic stockpile more toilet paper," the study, published in journal PLOS ONE, read, despite toilet paper being utterly inadequate in terms of saving lives, no matter how much you have of it.
"This finding supports the notion that toilet paper functions as a purely subjective symbol of safety."
There had been fewer than 1000 deaths when New Zealand's first case was reported - the toll is now up to 435,000.
Older people were more likely to stock up than younger people, probably because they felt more threatened by the disease. A disproportionate number of those killed by COVID-19 are elderly.
"Older people are more prone to a severe course of the disease and, thus, may be more eager to prepare for strict self-isolation."
Another influence was whether people feel anxious in general.
A surprising finding was people who rank highly on conscientiousness were also more likely to stockpile. The researchers expected them to "refrain from impulsive panic buying due to increased self-control", but instead they appeared to make like the ants in the famous fable, and prepare for a winter without access to supermarkets.
"This finding implies that public communication is well advised to stress the functioning of supply chains and the long-term availability of vital commodities," the study said.
"Such rational appeal might exploit people's long-sightedness and effectively counter the dysfunctional intuition that commodities may become scarce in the near future."
Prime Minister Jacinda Ardern and supermarket bosses repeatedly urged people to chill out in February and March, saying there was plenty to go around and no threat to the supply of toilet paper. In the end they were right.
Our personality traits couldn't account for all the stockpiling, the researchers said. Americans stocked up more than Europeans, for example, though that might be because you can buy enormous 36-roll packs in the US quite easily.
"Some psychological explanations and situational factors likely remain unaccounted for [such as] malleable external factors such as the risk management by and trust in local authorities."
