Chex (Change History Explicit): New HCI Concepts for Change Awareness

Abstract

Current display technologies do not support users in the critical task of recovering their situation awareness by determining whether situations have changed in meaningful ways. By simply representing the current state of a situation, displays force users to rely on their own ability to extract changes by cognitively integrating events over time. A flood of recent experiments have demonstrated dramatic limitations in these cognitive processes, with humans unable to spot changes in simple scenes, even under optimal monitoring conditions (they show “change blindness”). Here, we develop and empirically evaluate a set of new HCI concepts, collectively called CHEX (Change History Explicit), for supporting improved change awareness in a naval air warfare domain in which users monitor an airspace. CHEX augments the human attentional system with a set of intelligent change detectors whose output is logged in a re-configurable table format that is linked back to the situation display. We show that CHEX is extremely effective both for maintaining situation awareness when monitoring a situation as well as when recovering situation awareness following an interruption. CHEX shows great promise for use in other domains as well.