In fact I would argue that rationalization is the default for human beings, and that anything else requires either focused effort or serious mental re-programming (which is still probably only partially effective).
Sounds about right. This would be why science is hard for humans. We wouldn't bother if it didn't work.
Anna Salamon and I are confused. Both of us notice ourselves rationalizing on pretty much a daily basis and have to apply techniques like the Litany of Tarski pretty regularly. But in several of our test sessions for teaching rationality, a handful of people report never rationalizing and seem to have little clue what Tarski is for. They don't relate to any examples we give, whether fictitious or actual personal examples from our lives. Some of these people show signs of being rather high-level rationalists overall, although some don't.