Then for a randomly selected subsample, the researchers supplemented the description of the drug trial with a simple chart. But here’s the kicker: That chart contained no new information; it simply repeated the information in the original vignette, with a tall bar illustrating that 87 percent of the control group had the illness, and a shorter bar showing that that number fell to 47 percent for those who took the drug.
But taking the same information and also showing it as a chart made it enormously more persuasive, raising the proportion who believed in the efficacy of the drug to 97 percent from 68 percent. If the researchers are correct, the following chart should persuade you of their finding.
What makes simple charts so persuasive? It isn’t because they make the information more memorable — 30 minutes after reading about the drug trials, those who saw the charts were not much more likely to recall the results than those who had just read the description. Rather, the researchers conjecture, charts offer the veneer of science. And indeed, the tendency to find the charts more persuasive was strongest among those who agreed with the statement “I believe in science.”
Charts = science? If veneer of science is the answer, why does the chart support science? Scientists are the ones who use charts? Or they are the ones who are trusted more with charts?
I wonder if there are other explanations:
1. Seeing a clear difference in bars (87% vs. 47%) makes a stronger impression than simply reading the difference. A 40% difference is abstract but is more striking in an image.
2. More people accept the power of visual data today compared to written text. Think of all those Internet infographics with interesting information.