The effect of background complexity and variability on visual search in video conferencing displays

The use of video conferencing tools increased significantly during the COVID-19 pandemic; however, there is little research on the visual factors that affect the video conferencing experience. For example, while searching for the current speaker, if a salient color is used as a highlight, it might “pop-out”, increasing the efficiency of search by drawing attention. However, the level of saliency depends on the characteristics of the display, which in turn may impair the ability to predict the efficiency of search and to design a salient highlight, especially when the user has the freedom to control their own backgrounds during video conferencing. In this study, we investigated the effect of background complexity and variability on visual search performance using video conferencing displays. Observers searched either for the current speaker whose image, as in typical video conferencing tools, was highlighted (Experiment 1) or for a raised-hand symbol embedded on one of the backgrounds (Experiment 2) while we recorded their search time and tracked their eye movements. The number of virtual attendees in the display, the complexity and variability of attendees’ backgrounds, and the presence of a target were manipulated. Results showed a classical set size effect and a significant effect of background complexity and variability, suggesting that search performance declined as the set size and visual complexity and variability increased. Our manipulation of background complexity was confirmed by a mathematical model of visual clutter. Further analysis revealed significant image-specific effects, suggesting that some backgrounds are sub-optimally designed from the point of perceptual processes.