A part of your brain can't tell the difference between what's on screen and what's real, which is why horror movies make your heart race. VR exploits this same mechanism, tricking your body into responding to simulated experiences as if they were actually happening.
That's why you can watch a scary movie and get scared. That's why you can watch an action movie and get excited. That's why you can watch porn and get aroused, because it's a part of you that can't tell the difference between something happening on the screen and something actually happening. And that's the part of you that we're altering, because your body is going to react to whatever that part of you believes to be true.
