The idea is that lack of awareness of the boundaries between processes such as reasoning and memory allows children to cross their boundaries to fill in gaps in knowledge or communication
There is some good evidence for this in the literature on children's ability to give eye-witness testimony. In particular, the work of Flavell. There is a recent book by B. Pillow, called: "Children's Discovery of the Active Mind: Phenomenological Awareness, Social Experience, and Knowledge published by Springer, 2012. I have tried to order an inspection copy, but the website doesn't appear to make this possible.
Thanks Brad. I just got your recent book which looks very intersting. I try to substantiate the argument that crucial turning points in reasoning development are associated with changes in the resolution of awareness about the differences between mental functions.
Not sure if this is what you are looking for, but there is work that shows that kids are prone to "premature closure" (see work from Acredolo and Horobin from the 80's). The idea is that kids focus on one possible answer as THE right answer without fully considering that there might be other possible solutions to the presented problem. This can be generalized to other investigations, e.g. to Ironsmith and Whitehurst's 1978 study on reference (where a child is asked "to point to 'the X'" when there are two X's...older kids would ask which one more reliably than younger ones). So, there is a "mix up" with knowledge and inference in the sense that inferentially they are arguably aware that there are two answers but immediate knowledge -- generated by the experimenter's request -- trumps this inferential process.
I'm not entirely sure if this is relevant but it strikes me that research into children's naive understanding (cf. Susan Carey, 1985; Karmiloff-smith, 1992) may be useful. The idea being that due to a lack of accurate knowledge and possibly a lack of executive function/working memory etc, young children are essentially using any means they can (which is where your question about crossing bounderies comes in) to access knowledge. Indeed this may even be the reason why young children often hold many misconceptions early on.....hope this helps, it's a different angle.
There's also some recent work on tacit/explicit understanding which may be of interest (cf. Kailli and Rainer)