Do partisanship and misunderstanding of exponential growth affect COVID-19 risk perception?

The guidance from scientific experts is clear: preventative measures such as social distancing and self-quarantine can help mitigate the risk of COVID-19 to oneself and to others. However, individual responses to the pandemic have been mixed, and public messaging from government officials (local, state, and federal) have been inconsistent. 

So what makes some more willing than others to engage in preventative measures? The Austerweil Lab at UW-Madison’s Department of Psychology is considering two plausible factors: 1) one’s belief about how quickly the virus spreads, and 2) whether one’s community “in-groups” are adopting preventative measures.

Without preventative measures or interventions, scientists believe that the virus spreads exponentially (doubling the number of cases about every 2-3 days). Previous research has shown that people are not good at understanding exponential growth. For example, a 1983 study found that people vastly underestimate the growth rate even when provided with more than enough information, and that the extent of underestimation differs based on an individual’s experience. However this study used inflation, not a virus, as its stimuli. 

Figure above shows number of positive COVID-19 cases increasing exponentially

“To my surprise,” says Assistant Professor Joe Austerweil, “there has been very little basic science conducted on human understanding of exponential growth, the cognitive mechanisms responsible for it, and how goals and experience influence reasoning, outside of some descriptive work from the late 1970s and early 1980s.” Austerweil, Assistant Scientist Jeff Zemla, and PhD student Michael Payton will probe whether people underestimate exponential growth of the virus that causes COVID-19 and whether this underestimation is linked to personal engagement of preventative measures such as social distancing. 

People are much more likely to engage in preventative measures when their community develops strong social norms that promote these measures. Anecdotally, responses to the COVID-19 epidemic appear to be influenced by one’s political preferences. This could be due to President Trump’s own messages which often contradict that of his own health experts, and/or from differences in media portrayal (liberal media sources have portrayed the virus as a more serious health risk than conservative media sources). 

“With respect to COVID-19,” says Zemla, “one hypothesis is that people engage in motivated reasoning: they selectively evaluate evidence to support a hypothesis that is consistent with their community’s beliefs. Our study will examine whether we can counteract these effects and see how political preferences interact with knowledge of how the virus spreads to affect individual preventative behavior and beliefs about the virus.”

As of April 1, the Austerweil Lab had collected 375 survey responses. They anticipate repeating a similar survey at different times during and after the pandemic to see how it has influenced people’s understanding of exponential growth.

April 10, 2020