Our senses and minds construct our reality. Both are inherently limited and we naturally seek tools to improve our experiences. Anyone who covers their ears as a siren roars past, turns on closed captions, or dons sunglasses on a bright day has altered ‘reality.’ As technology advances, we can also control reality with cutting-edge extended reality (XR) technologies, which add to, subtract from, and remap sounds and visuals in our world. A new and unexplored form of XR cognition aids involve “diminished reality,” where visuals and sounds from the environment are eliminated to direct focal attention, reduce distraction, and relieve the operator of the need to exert selective attention. This presentation will cover the perceptual and mental processes underlying XR cognition aids, with methods of testing the effectiveness of these aids, current domains of inquiry, and results from several laboratory experiments on how altering visual and auditory reality can affect performance, experience, and learning.