I can attest to having seen papers on this, but am not able to track them down right now. The theory is not dissimilar to rubber ducking- using your brain to wo

I can attest to having seen papers on this, but am not able to track them down right now. The theory is not dissimilar to rubber ducking- using your brain to work in the problem space- which helps transition your mental model to solution domain. Like you and others this experience with paper has also been my experience for decades. Perhaps of interest is that I transitioned from using paper to a Remarkable tablet, which is surprisingly great from a writing experience perspective, but which is deficient in the "paging through" experience that is so important with paper. Its still preferable to me to work digitally, and to unify around a device I can read on, and I am able to use it to work in problem domain reasonably effectively. HTH.