I'd be embarrassed to have you guys look into my kindle library. It's filled with all kind of non-fiction. However, I don't obsessively research for things that I simply don't understand. I have to have an interest. It could be because my child is sick, or I have a funny rash, or I can't freaking mix hot pink color for a painting. So I casted the middle vote. But, it's actually somewhere between the first and second option.
As to whether I retain it is questionable. I tend to remember things I want to remember. This is good and bad. This is one of the reasons why my hubs and I discuss things over instant messaging. I know that many of you are probably shaking your head on that, but it gets right down to the nitty gritty. What exactly do you mean? And there's a record of what was said. I'm embarrassed at some of them. What I thought I "read" and instead it meant something else entirely but I wasn't "reading" the words. Or things I thought about but didn't say (type). Yeah, Nam, those don't count.
I will research medical stuff until it gets to chemistry. Then I'm lost. (I took college chem and bio chem but obviously I didn't want to remember it! ;) ) With everything else, it's a "need to know" basis.