A Real-Time Approach to Capture Ambient and Focal Attention in Visual Search

During visual search, individuals’ attention shifts between ambient and focal states in response to task demands and stimuli. The ambient/focal coefficient K is a statistically validated measure of these states, computed offline from fixation duration and saccade amplitude data. While current methods compute K offline, real-time computation could enable applications such as monitoring user attention, creating attention-adaptive user interfaces, and optimizing graphics rendering. However, real-time computation of K requires stable estimates for the parameters of fixation duration and saccade amplitude distributions. Since these distributions are heavy-tailed, the real-time estimates exhibit high variance and slow convergence. To overcome this, we propose a robust parametrization and an alternative estimation method, along with two real-time measures analogous to K. Through a map viewing study involving localization and route planning tasks, we show that our proposed measures exhibit dynamics consistent with offline K.