Actually, zippie, I think it did answer your question. You asked why the villagers were programmed to stop studying the plants when they became adept, and Arthur's answer is that they weren't programmed to do that. They were programmed to make their own decisions, and that's what they decide to do. Much of what the villagers do is not predictable ahead of time. We do the best job we can of coding and testing within the time constraints that we work under.