NEWS about Google Glass is everywhere these days, and so are its critics.

Some charge it only with fashion crimes. Others worry about invasion of privacy: when out on a date with a Glass wearer, you won’t know if they are recording you — or Googling “seduction tips,” for that matter.

Nonetheless, most agree that a smartphone-linked display and camera placed in the corner of your vision is intriguing and potentially revolutionary — and like us, they want to try it. But Glass may inadvertently disrupt a crucial cognitive capacity, with potentially dangerous consequences.

In an impromptu TED talk and interview in March, Sergey Brin, one of Google’s founders, described a motivation for the new product. “We questioned whether you should be walking around looking down” at a smartphone, he said. Instead, the company’s designers asked, “Can we make something that frees your hands” and “frees your eyes”?

Google isn’t the only company selling a technology that makes it easier to use your phone while you do other things. Last month Chevrolet released a commercial touting “eyes-free and hands-free integration” with the iPhone’s Siri interface, showing a woman checking her text messages using voice commands while she drives in circles.