Melting into shadow: Toward less cognitively loaded communication in the dark

As digital devices become an integral part of daily life, people are increasingly experiencing fatigue from constant exposure to information. For example, videoconferencing has been found to cause fatigue, attributed to the cognitive load caused by constant exposure to the gaze of multiple persons and the effort to acquire limited non-verbal information from visual sources. However, current videoconferencing and VR technologies are being developed to increase the amount of visual information to enhance telepresence, resulting in a higher cognitive load.Therefore, in this study, we focused on low-light environments where the amount of visual information is low, and by using shadows instead of camera images as a communication interface, we developed a system that enables communication with people in remote locations with low cognitive load for long periods of time without disturbing their immersion in other content. We conducted an experiment in which participants were asked to read a manga for 5 minutes while engaging in a brief conversation about the manga by using this system every minute. The results showed that the system significantly reduced vertical eye movement compared to videoconferencing using a display (p < 0.05) and that the system did not interfere with concentration on reading manga more than videoconferencing. These results suggest that this system is more effective than videoconferencing in terms of sharing the same time with person located remotely with minimal cognitive load, even while they are connected for a long time and doing in different activities.