Cute experiment, but I'm not sure the results of a "game" can be generalized to how people feel about working and accumulating wealth. At a glance, I'd think competitive people would be more motivated to "earn chocolates", even if they couldn't eat them . . . but in real life, that same competitive spirit might not manifest itself in the desire to earn more money -- it could mean they're more likely to want to buy stuff, which is more visible to other people.
And chocolates aren't the same as money for the rest of your life.
Personally, I have more right now than some people on this board who have already retired, but my personal "comfort zone" is a little higher. I'm more concerned about increasing costs in the future, and with my genes I'm likely to live much longer than average. I would rather work a few more years NOW than find myself forced to return to the work force at a later date. My choice to continue working "a couple more years" might not make sense to other people, but it doesn't mean it's not the right choice for me.