I’ve written a great deal over the years about statistical narrative: telling stories with data. I often refer to the messages that we communicate with data as stories and talk about data analysis as the process of finding the stories that dwell in data. I describe one of the primary uses of data visualization as storytelling, but I’m a little uncomfortable when I do. Let me explain why.

A few days ago I was sent a link to an article by Saul Hymes, a medical doctor, titled “Give It Your Best Shot.” The subtitle, “A better narrative is required to counter the anti-vaccine movement’s fairy tales,” reveals the important concern that this article addresses. You’ve no doubt heard the claim that autism is caused by vaccinations. You’ve probably seen former centerfold Jenny McCarthy on TV warn against the risk of vaccinations as she tells the sad story of her autistic son, Evan. Perhaps you saw the Oprah Winfrey Show when McCarthy appeared as a guest and heard Oprah read a statement from the Centers for Disease Control (CDC) that “science has shown from multiple studies that there is no evidence that vaccines cause autism.” If so, you heard McCarthy reply, “My science is Evan, and he’s at home. That’s my science,” to which the audience responded with tearful applause. McCarthy made her case with a story.

The persuasive mechanism of stories is usually emotional, not rational. Stories ordinarily move us when they tap into our feelings, not our ability to reason. Storytelling with data, when true to its purpose, however, appeals to reason, asking people to think rationally and be moved primarily by what they come to understand, not by what they feel. What Saul Hymes admits in his article, much to his discomfort as a scientist and physician, is that he sometimes gives up in his attempt to persuade patients by presenting facts and switches to stories that do an end run around reason by targeting emotions. He does it, despite his scientific perspective and reliance on evidence and reason because it gets the job done, but he does so uncomfortably.

When I tell stories with data, I often include elements that people can connect with emotionally, but I try not to rely on the power of emotion as the primary mechanism of communication and persuasion. By using emotion as the primary mechanism, I would be tapping into a lesser-evolved part of humanity, and in so doing, miss an opportunity to help people learn to make better decisions through reason. I’m not saying that emotion isn’t important and that we’d be better off without it, but instead that emotion and reason have different strengths and serve different decision-making purposes. We become our better selves when we learn to recognize this difference and put reason in the driver’s seat when it’s needed. If I appealed to emotion to win my case when reason was needed, I would achieve the desired outcome, but not in a way that would help people make better decisions on their own in the future. Fighting feeling with feeling, even when done for the greater good, would seem like a betrayal of everything that I’m striving so hard to promote in my work.

We humans have evolved in a way that enables us to think rationally, which is an amazing gift. It is because of this ability that we can develop technologies that extend our reach and we can deal with one another in ways that make the world safer and more just. When emotion ties us together in compassion and mutual respect, we benefit from our pre-human ability to feel. When emotion, however, leads us to react in hateful ways that do harm, we must learn to shift into reason and rise above our emotional instincts.

By telling stories with data that rely on evidence and reason to persuade, we can help people learn to rely on this ability more naturally and habitually. If, however, we continue to replace evidence and reason with emotion rather than using it only to complement data, we encourage humanity to remain stuck, and the world will suffer. When we visualize data using means of representation that are inaccurate and difficult to perceive in an attempt to make them eye-catching and fun, we shift the means of communication and persuasion from reason to emotion. However, when we appeal to people’s emotions strictly to help them personally connect with information and care about it, and do so in a way that draws them into reasoned consideration of the information, not just feeling, we create a path to a brighter, saner future.

Take care,