Villagers will tend to be more diverse in their activities as the game progresses. You can control, to a degree, which job they will perform most often by selecting a preferred skill for each of them. However, keep in mind that they will continue to show a preference for what they're good at. So, for example, if you try to retrain a Master Scientist as a farmer and change their preferred skill from research to farming, (s)he will still probably be at the research table more often than the berry bush or farm, because they aren't any good at farming and don't want to do it!

Allowing their sense of security to dwindle with the food supply can backfire, though. They could just as easily abandon their jobs and pace in village center, "worried about food."

Individual villagers also display differing levels of aptitude and initiative, be design. Some seem to take forever to "get it" in one skill, while learning a different skill immediately. Some are free spirits, while others are industrious. That can create uneasiness for game players who want a high degree of predictability in how a game behaves. I used to get frustrated with them because they wouldn't do exactly what I wanted them to do all of the time. These days I just make sure that I have each villager "set up" the best that I can, and allow them the freedom to make their own choices most of the time. When I have am occasional "control freak attack" come over me, I can still intervene like crazy and make them do precisely what I want.
