Wish I had a definitive answer. I do know from personal experience that when I'm touch typing notes while reading a book or listening to a lecture, my thoughts drift fairly often. (I'm a fairly fast touch typist though, 140+ wpm.) I'm also more likely to be thinking, "damn, that's a lot of notes!" rather than about the material, lol. Whereas while handwriting, I'm heavily engaged with the material, to the point where I lose sight of the fact that I'm in the middle of taking notes.

Oh and because it's so easy to make quick edits while typing, I find it hard to resist the impulse to correct a typo or add an extra word here and there, which further distracts me from the material.

Also, I can touch type for long stretches without the slightest mental fatigue, but I need a tiny mental break after 30-60 seconds of handwritten note taking.