Utilizing graphical formats to convey uncertainty in a decisionmaking task

Understanding how to display effectively uncertain information has become increasingly important as decision aids can provide operators with situational estimates and their associated uncertainty. The paper describes two studies in which degraded or blended icons were used to convey uncertainty regarding the identity of a radar contact as hostile or friendly. A classification study first showed that participants could sort, order and rank icons from five sets intended to represent different levels of uncertainty. Three icon sets were selected for further study in an experiment in which participants had to identify the status of contacts as either hostile or friendly. Contacts and probabilistic estimates of their identities were depicted on a simulated radar screen in one of three ways: with degraded icons and probabilities, with non-degraded icons and probabilities and with degraded icons only. Results showed that participants using displays with only degraded icons performed better on some measures and as well on other measures, than the other tested conditions. These results are significant because they indicate both that people can understand uncertainty conveyed through such a manner and thus that the use of distorted or degraded images may be a viable alternative to convey situational uncertainty.