Icon Arrays Reduce Concern Over COVID-19 Vaccine Side Effects: A Randomized Control Study

On April 13, 2021, the CDC announced that the administration of Johnson and Johnson’s COVID-19 vaccine would be paused due to a rare blood clotting side effect in ~0.0001% of people given the vaccine. Most people who are hesitant to get a COVID-19 vaccine list potential side effects as their main concern (PEW, 2021); thus, it is likely that this announcement increased vaccine hesitancy among the American public. Two days after the CDC’s announcement, we administered a survey to a group of 2,046 Americans to assess their attitudes toward COVID-19 vaccines. The aim of this study was to investigate best practices for communicating information about the risk of side effects to the public. We found that the use of icon arrays to illustrate the small chance of experiencing the blood clotting side effect greatly decreased reported aversion toward the Johnson and Johnson vaccine as well as all other COVID-19 vaccines.

Adults' Health-Related Problem Solving Is Facilitated by Number Lines, But Not Risk Ladders and Icon Arrays

Visual displays, such as icon arrays and risk ladders, are often used to communicate numerical health information. Number lines improve reasoning with rational numbers but are seldom used in health contexts. College students compared rates for information related to COVID-19 (e.g., number of deaths and number of cases) in one of four randomly-assigned conditions: icon arrays, risk ladders, number lines, or no accompanying visual display. As predicted, number lines facilitated performance on these problems – the number line condition outperformed the other visual display conditions, which did not perform any better than the no visual display condition. In addition, higher performance on the health-related math problems was associated with higher COVID-19 worry for oneself and others, higher perceptions of COVID-19 severity, and higher endorsement of intentions to engage in preventive health behaviors, even when controlling for baseline math skills. These findings have important implications for effectively presenting health statistics.

Using Icon Arrays to Communicate Gambling Information Reduces the Appeal of Scratch Card Games

The present study assessed how altering the presentation format of readily available gambling information influences individuals’ gambling-related judgments (e.g., their perceived odds of winning a prize). Across two experiments (N = 1,151), we find that using icon arrays to present gambling information reduces the appeal of scratch card games. That is, participants presented with gambling information in an icon array, as opposed to a non-graphical format, reported feeling less likely to win a prize, less excitement to play, and less urge to gamble on a scratch card game presented in a hypothetical gambling task. The present study highlights how presenting gambling information in a simple graphical format (i.e., an icon array) can impact gambling-related perceptions and judgments. Overall, we conclude that presenting readily available gambling information in an icon array format represents a simple yet promising tool for correcting gamblers’ often overly-optimistic perceptions and reducing the appeal of negative expected value scratch card games.

Effect of Tabular and Icon Fact Box Formats on Comprehension of Benefits and Harms of Prostate Cancer Screening: A Randomized Trial

Background. Fact boxes employ evidence-based guidelines on risk communication to present benefits and harms of health interventions in a balanced and transparent format. However, little is known about their short- and long-term efficacy and whether designing fact boxes to present multiple outcomes with icon arrays would increase their efficacy. Method. In study 1, 120 men (30–75 y) completed a lab study. Participants were randomly assigned to 1 of 3 fact box formats on prostate cancer screening: a tabular fact box with numbers, a fact box with numbers and icon array, and a fact box with numbers, separate icon arrays, and text to describe each benefit and harm. Comprehension of information (while materials were present) and short-term knowledge recall were assessed. Study 2 recruited an online sample of 244 German men (40–75 y). Participants were randomly assigned to 1 of the 3 fact box formats or widely distributed health information, and knowledge was assessed at baseline, shortly after presentation, and at 6-mo follow-up, along with comprehension while materials were present. Results. In both studies, comprehension and knowledge-recall scores were similar when comparing tabular and icon fact boxes. In the 6-mo follow-up, this positive effect on knowledge recall disappeared. Fact boxes increased knowledge relative to baseline but did not affect decision intentions or perceptions of having complete information to make decisions. Conclusions. This study shows that fact boxes with and without icon arrays are equally effective at improving comprehension and knowledge recall over the short-term and are simple formats that can improve on current health information. Specifically, if fact boxes are used at the time or immediately before a decision is made, they promote informed decisions about prostate cancer screening.

Do Icon Arrays Help Reduce Denominator Neglect?

Background and Objective. Denominator neglect is the focus on the number of times a target event has happened (e.g., the number of treated and nontreated patients who die) without considering the overall number of opportunities for it to happen (e.g., the overall number of treated and nontreated patients). In 2 studies, we addressed the effect of denominator neglect in problems involving treatment risk reduction where samples of treated and non-treated patients and the relative risk reduction were of different sizes. We also tested whether using icon arrays helps people take these different sample sizes into account. We especially focused on older adults, who are often more disadvantaged when making decisions about their health. Design. Study 1 was conducted on a laboratory sample using a within-subjects design; study 2 was conducted on a nonstudent sample interviewed through the Web using a between-subjects design. Outcome Measures. Accuracy of understanding risk reduction. Results. Participants often paid too much attention to numerators and insufficient attention to denominators when numerical information about treatment risk reduction was provided. Adding icon arrays to the numerical information, however, drew participants’ attention to the denominators and helped them make more accurate assessments of treatment risk reduction. Icon arrays were equally helpful to younger and older adults. Conclusions. Building on previous research showing that problems with understanding numerical information often do not reside in the mind but in the representation of the problem, the results show that icon arrays are an effective method of eliminating denominator neglect.