I must commend you on your fine research on memory, well described in this article. My own research has been with preschoolers, and it strikes me that relative size of objects in this population might be interpreted and remembered differently because of distinct life experiences. That is, unusually small items are "toys" and very large items are "monsters" in their parlance, I found, both highly salient categories compared to ordinary objects found in adults' lives. If you could revise your experimental procedures a little and repeat them with 3- and 4-year olds, you might find some surprises!