A farm oaf knows how to grow food by long experience, but cannot do research.
Colonists develop - and destroy - relationships. They respond to hunger and fatigue, witnessing death, disrespectfully unburied corpses, being wounded, being left in darkness, getting packed into cramped environments, sleeping outside or in the same room as others, and many other situations. You’ll acquire more colonists by capturing them in combat and turning them to your side, buying them from slave traders, or taking in refugees.