When I say "stimulus" I mean a lot more than a "flash of light" - Amos, to get back to where I was before my Internet went away.

For instance, there are bilinguals who can use either language in any situation, and others who get used to communicating in one language at a time (because they live or work or otherwise have daily interactions with people who don't or won't speak the other). With a computer and reaction-time I was able to show that this common usage of one language per conversation works by inhibiting the other, unused/unusable language, not by activating the language that is actually chosen.

It was cool stuff and explained why, growing up in both English and French which my family mixed freely, I had friends who were perfectly fluent in French at school and in English at home, but who couldn't follow my conversations with my sisters.