Wow, I'd like to read the study. That really doesn't match up with my experiences reading and re-reading... at all. I usually get much more detail out of a text the second time, and some books (especially some fiction) rewards reading more than twice.

It sounds more like you want to learn to learn.

Take notes. Apply information as you come across it. Learn how your brain stores information and take advantage of that. Learn things as though you're going to teach them.

I second this. By Appling the info you find out what you don't know. We fool ourselves into thinking that we know more than we do.

When we reread we tend to skip things that we think we know but don't.

Don't have too much faith in those studies. Has it been reproduced by an independent group? Do you have a link?

What kind of material you want to learn? How long is the book? The tricks to learn each subject may be different.

Abstract algebra, research papers. I know I need to make up my own problems as I go along with it, but that is easier said than done.

In the books of abstract algebra, try to read carefully without skimming. Skimming is a big temptation.

Use a lot of paper and pencil (and a trash bin) to copy the proofs and the solution of the solved problems. (Bonus points if you can think variants, and prove the variants or understand why the variants are false.)

Use more paper and pencil to solve the exercises.

For the research papers, the problem is that the style is too short. You must fill the blanks, and sometimes they are not obvious. In the first papers of a subject you may have to go very slowly, perhaps one page per hour or even slower. Copy the proof and fill all the blanks. [Note that the introductions and conclusions are sometimes too optimistic.]