I don't understand what conclusions you can draw from an experiment with a predefined termination date like this. If I were part of this group, I would realize

I don't understand what conclusions you can draw from an experiment with a predefined termination date like this. If I were part of this group, I would realize that in two years, I am back to supporting myself, so I would keep working the entire time. If instead I knew my basic needs would be covered for free for the rest of my life, I might just quit my job and enjoy life. As someone else posted here a long time ago, a better way to estimate the effects of UBI on productivity is to study people living off a lottery annuity of a similar allowance.