How Handheld Mobile Device Size and Hand Location May Affect Divided Attention

Previous research demonstrates that people increasingly utilize multiple displays along with mobile devices simultaneously, and that this split in attention has detrimental effects on goal-directed behavior. However, few studies have assessed the impact of the physical attributes of mobile devices–including dimensions, weight and screen size–on attention. Understanding how device dimensions and screen size affect attention is an important first step in creating safety guidelines for high risk industries that utilize displays, such as automotive and aeronautics engineering. The aim of this work is to determine to what extent the display dimensions and screen size of mobile devices influence attention. To explore this question, participants interacted with mobile devices of varying sizes while performing a change detection task on a stationary device located behind and above the mobile device. Results of this study suggest that those using a smaller mobile device achieved higher performance on the background change detection task than those using a larger device, while having similar performance in the mobile device task. This work demonstrates that when attention is divided, larger displays may be more attentionally demanding. We recommend that when users or designers are required to consider multitasking between a foreground and background task, in order to optimize background performance they should utilize smaller foreground displays.