Analogous to the introduction of colour displays, 3D displays hold the potential to expand the information that can be displayed without increasing clutter. This is in addition to the application of 3D technology to showing volumetric data. Going beyond colour, separation by depth has in the past been shown to enable very fast (‘parallel’) visual search (Nakayama and Silverman 1986), something that separation by colour alone does not do. The ability to focus attention exclusively on a depth plane provides a potentially powerful (and relatively practical) extension to command-and-control displays. Just one extra depth layer can declutter the display. For this reason we have developed a ‘Dual-layer’ display with two physically separated layers. As expected, conjunction search times become parallel when information is split into two depth layers but only when the stimuli are simple and non-overlapping; complex and overlapping imagery in the rear layer still interferes with visual search in the front layer. With the Dual-layer cockpit display, it is possible to increase information content significantly without substantially affecting ease-of-search. We show experimentally that the secondary depth cues (accommodation and parallax) boost this advantage.

We expect the primary ‘declutter’ market to lie in applications that do not tolerate the overlooking of crucial information, in environments that are space limited, and in mobile displays. Note that the use of 3D to declutter fundamentally differs from the use of 3D to show volumetric spatial relationships.