The Swiss cheese pandemic defense metaphor
IAN MACKAY/VIROLOGYDOWNUNDER/BASED ON THE SWISS CHEESE MODEL BY JAMES T. REASON
If a photo can say a thousand words, an infographic on the coronavirus pandemic speaks volumes.
The “Swiss cheese model” of pandemic defense is so easy to grasp, thousands of people are sharing it on social media.
After reading about the useful metaphor in The New York Times, I contacted its creator, Australian virologist Ian Mackay. We talked about why he created it, how to interpret it, and what lessons we can learn from the visualization.
The simple graphic shows ten cheese slices. Each slice represents a layer of protection that helps prevent the spread of coronavirus. For example:
- Physical distance
- Masks
- Quarantine and isolation
- Vaccines
“It gives you the idea that it’s not just one thing that will protect you and keep you safe from getting the virus,” Mackay told me.
“Masks alone are not going to do it. Neither is physical distancing by itself. It will take a lot of things to reduce the risk.”
The Swiss cheese metaphor works well to explain the layers of protection required to slow the spread because each slice has holes. The virus can pass through holes, but adding slices builds a stronger and stronger defense.
In the simplest medical terms, each ‘intervention has imperfections.’ An even simpler explanation is to put up an image of Swiss cheese slices to explain that every layer has holes. More layers (slices) will build a strong barrier to reduce the spread.
“Think of it as a package of cheese rather than individual slices that you can pull out,” says Mackay. “You can’t just do one. It’s about the whole package reducing your risk.”
There are three elements of the infographic that make it effective.
1. It’s visual
Long before our ancient ancestors developed language, they drew pictures on cave walls to share stories and information. We’re visual beings. We like to see pictures.
2. It’s a metaphor
More than 2,000 years ago, Aristotle recommended the use of metaphor as a persuasive technique in public speaking. “The greatest thing by far is to be a master of metaphor,” he said.
Think of metaphor as a mental shortcut. It helps explain a complex idea by comparing it to something familiar.
3. It’s (almost) universal
Mackay acknowledges that Swiss cheese is not well known in every part of the world, but it’s close enough to being universal. For a metaphor to work, it has to be instantly recognizable to a majority of your audience.
Take another look at the Swiss cheese graphic. Right in the middle is a tiny mouse nibbling away at a slice. It’s called the ‘misinformation mouse’ which, left unchecked, will create even bigger holes in each layer of protection.
Mackay posted earlier versions of the graphic on Twitter and asked for feedback. Someone else came up with the idea of the mouse. The lesson? An effective metaphor is hard to create. It helps to collaborate with others.
In fact, Mackay credits cognitive psychologist James T. Reason for coming up with the original Swiss cheese metaphor which Reason applied to a variety of accidents. Mackay believed it was an appropriate metaphor to explain risk mitigation measures that apply to the pandemic. And he adapted it from a visual that he saw on a site called Sketchplanations.
Metaphors take work.
Mackay, a virologist at the University of Queensland, maintains his own blog where he explains medical concepts in everyday language.
Mackay has a critical message for experts, educators, and government agencies whose job it is to communicate information about the vaccine and other health measures.
“Never expect that people will understand any single word that you are going to say. Break the language down into the simplest words you can use. Don’t just assume people have the background you have.”
Mackay urges experts who have analyzed the vaccine trial data to get in front of the cameras early and often and to share their findings in plain, simple language.
“You just can’t communicate enough,” he says.
Complex ideas require simple explanations. If people don’t understand the topic, they’ll be less likely to change their behavior or take a recommended course of action.
There’s power in a simple metaphor.