The only EEG stuff I've seen before was Mick Grierson using it at a dorkbot-style event to 'find out' if a friend of his 'is gay' (take this in the childish scoffing at the notion of homosexuality sense of things). Over a period of 5 minutes, Mick flashed up fast, subliminal homoerotic pictures on a projector, in amongst a control set of heteroerotic images, and monitored the EEG waves for spikes suggesting subconscious approval.
It was just a joke ofcourse, the entire setup was comical and ad-hoc, and anyway, it was done in a pub. Mick had to apologise several times for perceived 'errors' during the demo sequence, which was supposed to convince the audience before the show that the gear was set up correctly.
But it did demystify EEG as an sensor - after all, data from many of the other sensors that artists and designers use aren't always so reliable. And when I came across Unstable Empathy today, it made me think about the way audience members 'test' sensor driven artworks before they are willing to engage with them.
In shows with an open audience who are freely moving around and can all see each other, participants can't help but place a weight of expectation on the technology. They are in a group after all, and if the technology doesn't live up to it's end of the bargain, the participant can end up 'making a fool of themselves' - waving their arms around, waiting for a response from the artwork. So people usually 'test' the work to make sure it's going to give them 'justification' for thier abnormal movements, before they 'open up' to it and trust it.
It's a barrier to engagement with an artwork. If the artist creates a direct and clear response with a stable technology, the audience get the gratification very early, but then you are left with a relatively superficial experience in which the audience member feels safe and the novelty wears off after 10 seconds.
But another way round the problem, like Unstable Empathy, is by serving only two participants at a time - forcing people to 'step away' from the group in order to participate. Trust in the work will come much sooner as there is nothing to lose in terms of judgements by your peers. In fact the only person who could possibly judge you is the other participant with whom you are in dialogue - via the artwork. So in order to participate, you have to trust the artwork, as it's your only mode of expressing yourself.
If your artwork involves interaction between audience member and artwork (rather than audience member and audience member), perhaps another way to do this is to put up a curtain, and let in one, two or a small group at a time.
Just a couple of thoughts there on ways to lower the engagement barrier to your artworks.