Designed by Neurable, a small start-up founded by Ramses Alcaide, an electrical engineer and neuroscientist, the game offers what you might call a computer mouse for the mind, a way of selecting items in a virtual world with your thoughts. Incorporating a headset with virtual reality goggles and sensors that can read your brain waves, this prototype is a few years from the market. And it is limited in what it can do. You cannot select an object with your mind unless you first look in its general direction, narrowing the number of items you may be considering.

But it works. I recently played the game, which has the working title Awakening, when Mr. Alcaide and two Neurable employees passed through San Francisco, and a few hundred others tried it this month at the Siggraph computer graphics conference in Los Angeles.