Because I'm a nurse IRL, I did an an experiment. I made everyone in the village a Doctor to see how long and how well they'd survive. Guess what? They didn't last beyond a week!!! (Proved what I've always suspected...heheheh)

So did you not have anyone farming or doing research? What did they die of?

I got them all to trainee doctor status, turned off all preference checkmarks and just let them go. They failed to provide enough food or reproduce.

Especialy at the beginning of the game, you can't let your villagers alone too much!

The doctors will never heal anybody by their own if they are not checked as Doctors. That's like that since the 1st VV!

And it's right for the others skills, more or less. When they are Master on something they tend toward of doing it by their own.

I never quit my game without checking at least 2 doctors and 1 farmer! (it may be more, depending of how many villagers I get)

Sometime, you may see a villager who LOVES doing a task. Even if you check and put him on another task, he'll go to do the one he prefers, time to time! I think even the LDW team doesn't know why and is still amazing about that! Me, I love it!