I took part in an ERP study on Wednesday.
Here I am:
That white things in that cap on my head are electrodes that are going to measure what's going on in my brain (as a measure of what's happening on my scalp) in response to linguistic stimuli. You can read about it here on wikipedia.
What you can't see, and may not know if you've never done an ERP study, is that there is a tremendous amount of gel that has to be injected into those electrodes so that they can make good contact with your scalp.
After the experiment you look pretty slick. And then the gel dries and you look like you have serious dandruff.
However, it was fun. And in addition to the free hair gel and coif, I got a cookie for my participation. And, of course, I got to contribute to scientific discovery.