Virtual reality has gotten really good over the last few years, but with a few exceptions, the “reality” part ends up getting restricted to sight and sound. You put on the headset, plug in the headphones, and that’s your experience. The rest of our senses usually get left out, most often for totally reasonable technical reasons. Like, yeah, you can totally feel touch and temperature sensations in VR as long as you’re willing to stick your hand in a giant mystery box and leave it there or (more recently) wear some expensive gloves attached to an even more expensive pair of robotic arms.
For bespoke, practical VR, that’s probably fine, but for the kind of really immersive VR that you’d want for gaming, it’s important to not feel constrained by the hardware that would be required—anything that’s going to add an extra sensory dimension ends up that much more stuff that has to be powered and is hanging off of you somewhere.
In order to replicate temperature sensations in VR, for example, the go-to hardware has been Peltier elements, which can do thermoelectric heating and cooling of whatever they’re attached to. They work well enough, but they’re power-hungry, making them impractical for long-term use while reliant on batteries. And other VR temperature solutions, like heat lamps, are even worse.
Researchers from the University of Chicago have come up with a much more power efficient way of generating different temperature sensations in VR, and they’ve done it by hacking into your face. By using very specific chemicals to access the trigeminal nerve in your nose, they can make you feel hot and cold through smells without realizing you’re smelling anything at all.