Thermal Pain and Detection Threshold Modulation in Augmented Reality

Augmented Reality (AR) overlays computer-generated visual, auditory or other sensory information on the real world. Due to recent advancements in AR it can be difficult for the user to differentiate between sensory information coming from real and virtual objects, leading to interesting phenomena. For example, an AR experience in which users can experience their own hands in flames has been shown to elicit heat illusions on the affected hands. In this study, we investigate the potential that AR has for top-down modulation of pain and thermal perception. We assessed thermal pain and detection thresholds on the participants right hand when they experienced that hand covered in virtual flames in AR. We compared that experience to a baseline condition with no additional stimuli as well to a control condition that sees the hand covered by unrealistic blue flames to compensate the distraction factor. We found that experiencing a burning hand in AR induced analgesic and hyperalgesic effects as participants began to feel heat related pain on lower temperatures and cold related pain on higher temperatures. That experience also significantly changed the lowest temperature at which participants started perceiving warmth. These results demonstrate that pain and thermal perception can be manipulated by altering the perception of our body in AR.