Various studies have shown that adherence to social distancing rules during the Covid-19 pandemic has been variable.  There are various reasons for this, from one’s age, political persuasion or religious belief, but new research from the University of Cologne suggests our understanding of exponential growth is also a factor.

Across three experiments with several hundred volunteers, the researchers found that the majority of people erroneously believed that the number of Covid-19 cases grew linearly over time, rather than exponentially.  This led to them underestimating the growth of the virus.  When interventions were enacted to rectify this mistaken belief, not only did understanding of the virus grow, but so too did support for social distancing measures.

Appreciating the danger

Attempts to stem the spread of the virus via methods such as social distancing have been hampered by a large number of people doubting the need to follow such guidelines.  It’s a problem the researchers believe has roots in something known as the exponential growth bias.

“In general, people have difficulty understanding exponential growth and erroneously interpret it in linear terms instead,” they explain.  “The result is a gross underestimation of the growth of the infection rate and a misunderstanding of the potential to slow it down through social distancing.”

The experiments revealed that this misunderstanding of the exponential nature of the virus often fell along political lines, with conservatives less likely to understand exponential growth than liberals.  The results showed that overcoming the exponential growth bias was a significant factor in growing support for social distancing measures, as it meant people appreciated the threat the virus posed.  It’s a finding the researchers believe highlights the importance of statistical literacy among the population.

“Our results stand in contrast to earlier literature showing that the exponential growth bias is difficult to overcome,” they say. “The reason for this is that the current study focuses on a threat with great personal relevance and media presence, which likely increases subjective availability and thus the estimated probability of the risk.”