By Christmastime, you'll be able to purchase a headset that connects to your video game console. By thinking a command, you'll be able to tell that videogame to lift a rock or defeat an enemy or whatever: without lifting a finger, by only thinking and moving muscles in your face.
My question is, does this surprise you? More to the point, does it bother you that your PlayStation may be able to hear your thoughts?
This technology has actually been a long time in coming. Monkeys can move robot arms with their thoughts, parapelegics can move cursors on computer screens the same way, and now this, the commercially available alternative.
What's next is that this technology should get smaller and more nimble. I wouldn't be surprised if an option soon comes to install it inside you somehow, permanently attached (although I can see some anatomical limitations on the possibilities there, and if you're worried about a cell phone causing brain cancer, well, you won't even want to install a cellphone inside your skull). What it would be is a way to "throw your voice" to electronic devices by thinking.
This makes sense to me because I teach (for two lectures every winter) the exact mechanism of how a neuron works. The fact is that what you're thinking right now has a physical correlate. As you concentrate on something, tiny floodgates in your neurons open and close, making a wave of +-charged ions flow down the long, thin cell. (That's what the animation I mentioned last month was all about, actually.) Thoughts are physical, electrical events that can be detected with a physical, electrical device.
But while the thought is physical, the interesting thing about this applications (beyond their frivolity at first) is that they are centered around detecting your choice. In a sense, not subjugating free will but sensing and amplifying it. The TV remote or xBox controller detects your choice through the actions of your fingers. This headset detects it through the charges of your neurons. What's passive and active here is intensely important: the detector is passive, your will is active.
It's very important to watch out for technologies that may be active, not just passive, but I don't know of a way to change the brain signals electrically -- that's a much harder thing and may be physically impossible without invasive technology. This is just a way to detect them, and as such, it's a neat little gimmick and might help people without muscle function. It ultimately does not diminish your choice but amplifies it. And so it doesn't worry me, and I think it's kind of neat, with a little bit of wariness mixed in. Kind of like thinking about electronic voting machines ... wait, that might be a poor comparison ...
Here's the article about the technology: