Redundancy - Whole is More than the Sum of the Parts

Perhaps, the most important reason to use redundancy in displays is that our sensory systems work together in processing information. We are more likely to make correct judgments about stimuli or objects within our environment if we use input from more than one sense. Without input from other sense modalities, we can only identify 1/3 of odors. Odor identification speed and accuracy are improved when color cues are presented. In an eye-hand coordination study in a virtual reality environment, force feedback improved performance by 12%. When error reduction was factored in, the performance improvement was 20%. In another virtual reality study, tactile and olfactory cues significantly improved memory of the environment explored. In the research on tactor wristband use by pilots, the visual indicator plus wristband (tactile) condition resulted in 100% signal detection.

To create realistic interactions, training simulators replicate the controls of the "real" system in color, size, sound, texture, force feedback, and movement.