The game includes a few training sessions, in which the software searches for specific patterns of electrical activity that occur when I either think about lifting a rock or make the motion to lift. The program will then try to detect and respond to those patterns once play begins. In theory, I don’t actually need to imagine lifting the rock: any specific pattern of brain activity, or potentially even of muscle activity, could be tied to a command. If I repeatedly thought about pushing during the training period, the computer would consider that the signal to lift.
That calibration of the system isn’t always precise. During my test run, the rock rises into the air as I turn away from the screen to jot in my notebook. I also blow up a mountain without meaning to do anything. Drake explains this away, saying I’m like a wizard just learning to cast spells–“They sometimes go off when you’re not even trying.”
The Emotiv headset has two other purported powers, both of which might be more in tune with EEG’s strengths. Using muscle signals picked up from face and eye movements, it can read facial expressions, so it could help animate people’s avatars–their digital alter egos–in virtual worlds like Second Life. (Software-enhanced cameras are under development to do similar things.) More novel is the headset’s ability to roughly detect your state of mind–whether you are engaged (be it angry or attentive) or not. The sky in the martial-arts game glows orange when I begin to concentrate and fades to green when I stare out the window.
Chris Linder, a developer working on a game that will ship with the commercial version of the Emotiv device, says that his team most enjoyed designing features that capitalize on these two aspects of it. While Linder, the cofounder of Demiurge Studios in Cambridge, MA, doesn’t want to divulge details of his nascent game, he gives the example of allowing the player to walk on water–but only while maintaining a constant level of calm. “If you got too excited, you would just sink,” says Linder, whose company also developed some of the first games for the Wii.
About 50 miles south of Emotiv’s offices in San Francisco are those of its main competitor, Neurosky, which has taken a much simpler approach to creating a commercial EEG device. The headset it has developed has just one sensor, which rests on the forehead, and a built-in processor that analyzes incoming signals before wirelessly sending data to a computer.
The Neurosky device attempts to detect different states of mind by analyzing brain waves–rhythmic fluctuations in the voltage measured by EEG electrodes. While there is no one-to-one correspondence between mental state and a specific brain rhythm, scientists have reported specific links. Certain patterns of theta rhythms, which occur at a frequency of four to seven hertz, are linked to drowsiness. Alpha waves, eight to twelve hertz, are characteristic of relaxation. (Alpha waves can also be induced by closing the eyes.) Algorithms distill the electrical signals registered by the sensor into a single output number, which can then be used as an element of control in a video game or other application. A second set of algorithms is designed to detect a mental state the company dubs “meditation.” (As was the case with Emotiv’s device, muscle activity probably also comes into play here. When you’re trying to concentrate, for example, you are likely to sit still and not move your head or eyes; the abatement of muscle activity may factor into the device’s analysis.)
Playing a simple game designed to display the device’s capabilities, I successfully lift a virtual block into the air by concentrating. I also set a branch on fire by sustaining that concentration: the branch sparks and smokes and then explodes into flame, an unexpectedly satisfying experience. Then, I gamely focus inwardly and manage to raise a sunken plane from a lake.
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