I'm sure this experiment is to find adequate methods to stave off cabin fever. Simple things like altering the lighting is known to reduce problems by causing changes in shadows, etc.

Having an international crew for an expedition like this is likely to be helpful (if you're not hiring xenophobes) as it allows a greater variety of discussion. I'm British and living in Canada, and you wouldn't believe how much you have to talk about with complete strangers compared with someone of your own nationality. Add people in with differing skill sets and different language skills and you give people a vast amount to discuss before topics run out.