Attentional Issues with Superimposed Symbology: Formats for Scene-Linked Displays

https://doi.org/10.21949/14035771995PDFProceedingsHead up displaysInformation display systemsCognitionAttentionMotion perceptionHuman factorsResearchAttentional tunnelingDifferential motionScene-linked Heads Up Display (HUD) symbologySuperimposed symbologyUnited States. National Aeronautics and Space Administration. Operations BranchFoyle, David C.McCann, Robert S.Shelden, Stephen G.Ames Research CenterNTL-AVIATION-Aviation Human FactorsUS Transportation CollectionThe head-up display (HUD) has been shown to be a superior presentation methodfor flight path symbology over that of traditional flight director. Recentstudies, however, have shown that there are specific performance problemsassociated with HUDs. During simulated landing with superimposed HUD symbology,pilots took 2.5 seconds longer to respond to an unexpected runway incursionwhen the symbology was presented head-up than when head-down. This extends andreplicates previous research showing that superimposed HUD symbology may lead toattentional tunneling and inefficient processing of the out-the-window scene.In operational usage, superimposed symbology on a HUD is mostly presented at afixed, specific location on the HUD combiner, while the world scene behind itpitches, yaws, and rolls in response to aircraft motion. McCann, Lynch, Foyleand Johnston (1993) measured the time it takes to switch between the worldscene and the superimposed HUD symbology. They found that differential motionbetween the superimposed HUD symbology and the out-the-window scene led toincreased attentional switching time, and concluded that this differentialmotion may be the primary driver behind attentional tunneling. If the primarycause of attentional tunneling is differential motion between the HUD symbologyand the world, then removing the differential motion cues should minimize theattentional tunneling problem. One design option that achieves this goal is toreplace conventional HUD symbols with virtual symbols that appear to bephysically part of the world. Although rendered in graphics on the HUD, these"scene-linked" symbols are drawn, and move, as virtual objects in theout-the-window scene. As the aircraft moves through the world, thescene-linked symbols undergo the positional visual transformations as realobjects. There are no differential motion cues to cause the visual system tointerpret the virtual symbols as separate from the world. In the absence ofthese cues, attentional tunneling should be prevented, enhancing the abilityto process scene-linked HUD symbology in parallel with real-world information.6p.84