Getting a useful EEG reading is very hard, and usually requires shaving hair and applying conductive gel. My (admittedly speculative) guess, based on the product description ("two light-touch sensors on your forehead and ear"), is that it'd be a combination of voltage difference between the two points and _resistance_ between the two points (like a polygraph lie-detector). Those values will change all the time, due to factors you can and can't influence.
Based on that, I'd consider it likely that you _could_ trigger changes between ear-states, with practice, but that they'll still do whatever they want most of the time.
Ears that tracked eye position (facing the direction you're looking) or that point towards the nearest sound source would IMO be better as costume accessories, and would be easy enough to make.
Getting a useful EEG reading is very hard, and usually requires shaving hair and applying conductive gel. My (admittedly speculative) guess, based on the product description ("two light-touch sensors on your forehead and ear"), is that it'd be a combination of voltage difference between the two points and _resistance_ between the two points (like a polygraph lie-detector). Those values will change all the time, due to factors you can and can't influence.
Based on that, I'd consider it likely that you _could_ trigger changes between ear-states, with practice, but that they'll still do whatever they want most of the time.
Ears that tracked eye position (facing the direction you're looking) or that point towards the nearest sound source would IMO be better as costume accessories, and would be easy enough to make.