Effects of icon arrays to communicate risk in a repeated risky decision-making task

In two experiments, participants decided on each of several trials whether or not to take a risk. If they chose to take the risk, they had a relatively high probability (from 75% to 95%) of winning a small number of points and a relatively low probability (5% to 25%) of losing a large number of points. The loss amounts varied so that the expected value of taking the risk was positive on some trials, zero on others, and negative on the rest. The main independent variable was whether the probability of losing was communicated using numerical percentages or icon arrays. Both experiments included random icon arrays, in which the icons representing losses were randomly distributed throughout the array. Experiment 2 also included grouped icon arrays, in which the icons representing losses were grouped at the bottom of the array. Neither type of icon array led to better performance in the task. However, the random icon arrays led to less risk taking than the numerical percentages or the grouped icon arrays, especially at the higher loss probabilities. In a third experiment, participants made direct judgments of the percentages and probabilities represented by the icon arrays from Experiment 2. The results supported the idea that random arrays lead to less risk taking because they are perceived to represent greater loss probabilities. These results have several implications for the study of icon arrays and their use in risk communication.