I've been on three interviews now during which I have been asked a variation of this question:
The most popular variant is: "What would you do if you got behind on a project?" Not knowing the correct answer, I answer honestly: "Revisit the requirements." This is also the true answer in that I became familiar with the research to which Alice refers, although I usually wind up saying that working harder is an option if the work is sufficiently interesting.
But let me throw the question to my readers: what are interviewers expecting here? The simplistic answer is: "Sure, I'll work 14 hour days for you, such is my dedication to my work." But I'm pretty sure that's not it.
Another tricky one: having gone in to interview for a job in field X, the interviewer starts asking my thoughts on related fields Y and Z. Not knowing the correct answer, I answer (somewhat evasively) by talking about my experience in fields Y and Z to the extent I have it. If I don't, or if I'm otherwise cornered, I answer honestly: "While I will consider all offers, I believe my greatest potential lies in field X." But again let me ask my readers if they know what's being sought? This one, it seems, could go either way. On the one hand, the company might actually have work in fields Y and Z and needs employees to be flexible about their assigned tasks. On the other hand, saying that you'll do whatever sounds ingratiating and poorly specialized.