YOU open a door and it hits you – a flare of warmth on your skin. You brace yourself to go inside, battling smoke and heat. Flames flicker around you as you make your way through a burning building. You find what you came for and escape. Outside, it is so cold you start to shiver, while your hands and feet go numb.
But then you remove your headset and it all stops. You just finished an incredibly realistic training exercise. None of those sensations were caused by changes in your surroundings, although they felt real. Instead, chemicals carefully selected to mimic different feelings were pumped onto your skin.
Such stimulants have long been useful for understanding touch, the most complex of all human senses. In the 1990s, studies of capsaicin, an extract of chilli peppers, and menthol, found in peppermint, helped us pin down how our bodies react to hot and cold conditions. Now, Jasmine Lu and her colleagues at the University of Chicago are using this knowledge to create chemically induced sensations, to make virtual environments astonishingly realistic.
In a technology dubbed chemical haptics, they have built a wearable device that, when placed on the skin, can cause the wearer to experience a range of sensations – hot or cold, numb or tingly – on demand. Its uses could include creating intensely realistic virtual worlds for gamers to explore or for training firefighters. But will we ever be able to fully replicate the experience of touching something real, and what might we lose if we can’t? Amid growing talk about metaverses, such questions are increasingly important. “How we sense …
