My friend and fellow meteorologist writes a fantastic column for Forbes.com and this week's was especially noteworthy for me, because of the COVID 19 vaccine. A couple of friends and acquaintances have noted some hesitancy in getting the vaccine. The risks in getting a vaccines are much, much less than being struck by lightning or in a car accident.
Perceived Versus Actual Risk - Vaccine Lessons Meteorologists Understand
Forbes.com Dr. Marshall Shepherd April 14, 2021
This week the United States Centers For Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) raised concerns about the Johnson & Johnson vaccine. Distribution of that particular vaccine has been halted because of rare occurrence of blood clots in six women who received the shot. While the medical reasons for the pause are understandable under the emergency use declaration, I immediately knew this would set the U.S. back in its fight against COVID-19 and achieving immunity. Though only 6 cases out of nearly 7 million doses administered, I fully expected the “see I told you so” crowd and anti-vaccination movement to find a voice in this too. It is the perfect opportunity to discuss “perceived” and “actual” risk because it is something my colleagues in meteorology deal with often.
If you divide 6 by 7 million, a really, really small number is the outcome. In fact, that number works out to 0.000085714285 percent. This suggests that the risk, at least based on the sample of 6 cases, is extremely small of having the rare clots. According to the CDC, there is. 1 in 500,000 chance of being struck by lightning. In terms of percentage, that is about 0.0001999999 percent. People still go outside. This sets up a perfect discussion of perceived and actual risks.
A 2016 study in the Journal of Risk Research looked at how political ideology, socio-demographic background and climate change “beliefs” shaped a person’s perception of weather. The term “motivated reasoning” emerged in their analysis. Motivated reasoning is when people tend to consume or interpret evidence in a way that confirms what predispositions or what they already believe. By the way, you see this all of the time on social media. The study also found that people’s perceptions of weather often take precedence over actual weather.
Dan Gilbert wrote a 2006 opinion editorial in the Los Angeles Times on perceived and actual risks. Using the lens of global warming, Gilbert, then a psychology professor at Harvard, laid out four reasons people perceive risks as greater than or less than actuality:
- People overreact to intentional acts and under react to naturally-varying, generic, or accidental events. This probably explains why some people don’t have the same concern about being struck by lightning but are screaming loudly about the vaccine pause.
- People strongly react to things that offend their morals. Gilbert wrote, “Moral emotions are the brain’s call to action.” There are people that fundamentally are against vaccines or believe COVID-19 is a hoax. Yep, yikes. As such, their motivated reasoning causes them to react a certain way to the news about the Johnson and Johnson vaccine.
- People don’t react as strongly to threats perceived to be far off in the future as they do immediate risks. This is something that I hear all of the time about climate change even though the impacts are upon us now. I see it with extreme weather too. We continuously beg people to have tornado or hurricane plans in advance but often people are left scrambling to respond once the storm is upon them.
- People under react to slow changing processes or events. Gilbert writes, “Because we barely notice changes that happen gradually, we accept gradual changes that we would reject if they happened abruptly.” He goes on to give an example of Los Angeles traffic changes over the decades. However, I see similar parallels with hurricane warnings, sea level rise, and prolific infrastructure development in storm-prone areas.
It has always baffled me why folks with long metal rods would continue to walk around a golf course during a thunderstorm. I have always scratched my head when someone says, “I’ll evacuate if it gets to be a category 5 hurricane but I am staying at category 3.” People have flawed personal algorithms for how they perceive risk and often a healthy dose of the dreaded optimism bias. These four explanations by Gilbert also provide clarity.
Dr. J. Marshall Shepherd, a leading international expert in weather and climate, was the 2013 President of American Meteorological Society (AMS) and is Director of the University of Georgia’s (UGA) Atmospheric Sciences Program.
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