If you do a search you will find articles on this. Scientific American has published articles on how it improves learning.
My question is: Where are the products?
Actually this is so new, and potentially unfair for those that don't have it. But the current is supposed to be below the threshold of sensation, I think. It has been too long since I heard about this. I need a product that will improve my memory in an instant. There are so many files in my brain, I usually can't find what I want as fast as other people. But, I frequently retain things longer than my colleagues. I guess one would call that a trade off.
I would test this myself if I had more information. I suspect the polarity may be important. Oh, OH!! What if I had it backwards and it made me dumber?
Actually, I don't think it works that way. Let's see, I've got a nine volt battery and a battery clip..... Minus (i think) to the temple, plus to the tongue.....
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A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle