This is very interesting. Although I would want to see the research repeated in a different language culture, given the pictorial elements present in parts of Japanese script (do they actually use kanji in susbtitling, I wonder - more compact but harder to get the graphical definition). And also the fact that Japanese culture makes heavy use of pictograms and illustrations to convey information.

I think you would want to try it with a language culture for whom 'images are images and text is text', with a clearer gap between the two.