Impact of risk visualization formats on decision making

Abstract

This thesis investigates how exponentially increasing risks are understood and how this understanding leads to decisions. This research is grounded in two literatures: (lack of) understanding of exponential growth and risk visualization. It is well known that exponential trends are conceptually hard to grasp and many critical natural phenomena show exponential growth (e.g. viral spread, forest fires, cancer cell division). In many cases, exponential growth leads to exponential increases in risk and one efficient way to communicate such increasing risk is via visualizations. The present thesis investigated risk perception and decision-making when exponential risk information is presented in different formats. Participants completed a modified Balloon Analogue Risk Task (BART), in which they had to evaluate a number of scenarios with an already pumped balloon. The balloon’s popping probability always increased exponentially but depending on the type of the balloon the riskiness of each pump varied. The risk probabilities for each pump were presented in either a table or a line graph. Participants reported their risk perception for each scenario and whether they would pump the balloon. As expected, highly-educated participants were less likely to “pump” balloons as the popping probability and the riskiness of the balloons increased. However, visualization format had no effect on risk perception or decision-making. This finding suggests that participants were able to extract the critical information in a similar manner from both line graphs and tables and responded relying on both quantitative and visual information.