I sometimes think villagers have likes and dislikes which are not spelled out so we can see them.

I also think abilities are the same way. For example, in one of my games after I got a school and tapped on the drum a few times I bred a Master Scientist to a Master Scientist and according to the villager detail screen the resulting child had no skills, yet that child became an adept so fast it surprised me.

I started a new game today, and this time I had my villagers learn things all at once. Giggle. I had all six clustered about the same herbs and things the doctors study. One gal became a trainee before we made it to the cactus. Same with the research table, and berry bush. All made trainee status at different rates, making me think they do indeed have skills that we have to find out on our own. Which keeps my interest