Impact of Flashbangs on Eye-Behavior while Navigating and Performing Visual Search Tasks in Stressful Open-World Environments

In the field, Soldiers experience different situations that are potentially threatening and/or disorienting. One example is flashbang grenades, which are designed to incapacitate individuals by overstimulating both hearing and visual systems. Maintaining vigilance is imperative during search tasks and events like flashbangs can momentarily incapacitate visual capabilities, increasing vulnerability and reduce threat and target detection abilities. Understanding how visual capabilities are incapacitated can lead to the development of future technology. Here, we investigate how vision behavior changes directly following flashbangs to understand how these events impact visual behavior in certain environments. Twenty military personnel (including active duty and veteran personnel) freely navigated two different desktop environment themes: a neutral theme (construction zone) and a military theme (tanks, barbed-wire barriers, weapons, etc.) while searching for a vehicle target (N = 10) placed at pseudo-random intervals along the street, sidewalk, or alleyways. Both environments included on-theme background noises (e.g., jackhammer, gunfire). As participants navigated the environments, flashbangs (N=5) were triggered at different progress locations. Flashbangs included both a blinding light flash (~400ms duration) and a sharp ringing noise. We report results of significant differences in saccades, fixations, pupil dilation, and blinks between the environment theme immediately prior-to and after the flashbang. Together these findings demonstrate how flashbang events impact the ability to scan for threats and targets in the environment.