Icon Arrays for Medical Risk Communication: Do Icon Type and Color Influence Cardiovascular Risk Perception and Recall?

Background Icon arrays have been shown to be an effective method for communicating medical risk information. However, in practice, icon arrays used to visualize personal risks often differ in the type and color of the icons. The aim of this study was to examine the influence of icon type and color on the perception and recall of cardiovascular risk, as little is known about how color affects the perception of icon arrays. Methods A total of 866 participants aged 40 to 90 years representative of the German population in terms of gender and age completed an online experiment. Using a 2 × 2 between-subjects design, participants were randomly assigned to 1 of 4 experimental groups. They received their hypothetical 10-year cardiovascular risk using an icon array that varied by icon type (smiley v. person) and color (black/white v. red/yellow). We measured risk perception, emotional response, intentions of taking action to reduce the risk (e.g., increasing one’s physical activity), risk recall, and graph evaluation/trustworthiness, as well as numeracy and graphical literacy. Results Icon arrays using person icons were evaluated more positively. There was no effect of icons or color on risk perception, emotional response, intentions of taking action to reduce the risk, or trustworthiness of the graph. While more numerate/graphical literate participants were more likely to correctly recall the presented risk estimate, icon type and color did not influence the probability of correct recall. Conclusions Differences in the perception of the tested icon arrays were rather small, suggesting that they may be equally suitable for communicating medical risks. Further research on the robustness of these results across other colors, icons, and risk domains could add to guidelines on the design of visual aids. Highlights The use of different icons and colors did not influence the perception and the probability of recalling the 10-year cardiovascular risk, the emotional response, or the intentions to reduce the presented risk. Icon arrays with person icons were evaluated more positively. There was no evidence to suggest that the effectiveness of the studied icon arrays varied based on individuals’ levels of numerical or graphical literacy, nor did it differ between people with or without a history of CVD or on medication for an increased CVD risk.