Rock concerts and overcrowded buses – such scenes trigger revulsion in many who fear infection. | Image: Okan Caliskan/Pixabay

An aversion to crowds reduces the risk of infection. The Covid-19 pandemic has temporarily strengthened this protective mechanism in human beings, according to the work of researchers from Agroscope and ETH Zurich. In an online survey, they showed photos of an overcrowded bus and a well-attended rock concert to more than 1,000 test subjects from different countries. In 2020, the first year of the pandemic, the participants expressed greater feelings of revulsion than had been the case two years earlier. However, their sense of revulsion reduced again to previous levels just two years later – which was surprisingly quick.

J. Ammann & A. Berthold: Temporary differences in pathogen disgust sensitivity and the perception of crowded spaces. Personality and Individual ­Differences (2022)