Yeah, this tool seems like a pretty blunt instrument at this point. From the OP: > It is very difficult to target a specific region of the brain, especially w

Yeah, this tool seems like a pretty blunt instrument at this point. From the OP: > It is very difficult to target a specific region of the brain, especially with simple home set-ups that use wet sponges as the contact points. My layman's speculation is that things like cognition have complicated and fine-granted regulatory systems associated with them, which may have sub-optimal set-points for many people. To get true "cognitive enhancement" you'd have to 1) influence these systems in precise targeted ways (i.e. not with a blunt instrument) and 2) do it in a way that won't trigger counteracting regulation. Anything less would probably cause side-effects and/or be temporary with negative withdrawal symptoms.