Here is an article a reader of the NY Times linked to in a comment the other day, as proof that e-readers are terrible and no one should buy them for their kids. (The NY Times article was about the relative merits about the iPad versus the Kindle Fire.)
I think this is the worst kind of pseudo-science. The author references experts who merely give opinions (“‘There is physicality in reading,’ says… Maryanne Wolf”), and quotes as evidence of the inferiority of e-reading experiments that require students who grew up learning to read on paper to suddenly navigate well in a digital text. The only way I see to genuinely compare the effects of digital reading would be to teach a group of children to read on digital texts — no paper whatsoever — and a group to read on paper — no digital readers whatsoever — and then do experiments like the ones described.