OK, so, in a relentless quest to setup a function that executes life perfectly, I've gone to the ends of the earth to understand what it means to be an ENTP.
I'm not one, I don't think. Waaaay too quiet and faggy. But, come on: if all behavior has to arise from our biology, and our biology is to a certain and perhaps nominal extent modifiable, then one should be able to change one's personality by modulating these fundamental parameters, like horomone levels, receptor densities etc. Jungian typology apparently doesn't allow this, and I have no idea why. Maybe it's because Jung was a literal crackpot rather than a biologist.
Either way I'm sick of who I am and I'm going to be someone else.
Anyway, going back to the topic on hand (and being a complete hypocrite), one obvious parameter that is readily modifiable... is your brainwaves.
(Quick primer: your brain at any one time has "frequencies" of activity as well as amplitudes thereof. Higher frequencies are associated with greater wakefulness/arousal while lower frequencies are associated with sleep and such. Amplitudes correspond to an amount of activity. This is a gross oversimplification; you can read up on more if you get stuck. For reference's sake, when you're thinking of higher frequencies, think "fight-or flight", or test anxiety. Lower frequencies could be sleep or sleepiness, while a middle frequency would be closing your eyes briefly and relaxing.
Neurofeedback is basically hooking yourself up to a machine so you can see your brainwaves. You try to control what they are, and the machine gives you positive/negative reinforcement if you're meeting the goal. Some consider this a bit of a fringe medical treatment, but it's been used efficaciously to cure Autism and ADHD)
People have already looked at the MBTI and EEGs, and how they correlate with one another. In some cases, Jung was right -- extroverts are more chronically understimulated so they seek stimulating situations. Introverts are "overstimulated", and so don't. Some interesting findings: Sensors, when in a blank room, have activity patterns corresponding to that of near sleep. Intuitives can't help but look around and process.
I guess the million dollar question is this: If we know the brainwave correlates of certain modes of perception, can we train people to habituate those modes of thought and thus change their personality
The answer seems to be an obvious yes, but then the question remains about what the goals of such training would look like. If I'd get off my ass I wouldn't making short-and-sweet profiles for each type, with eyes-open and eyes-closed thinking states.
Jeeessuuuusss aren't I overblowing it.