The Reading Brain in the Digital Age: The Science of Paper versus Screens - Scientific American

[Igel]

12. Highlighting is often misused.

By highlighting it, it's a box that's checked off. "Yes, I've said this is important." That means no more attention gets paid to it. For poor students. Those whom were told highlighting isn't a tool, but a goal.

A good student goes back and pays special attention to the highlighted text, reviews it several times more often than the plain text.

And a good student highlights not whole sentences, not whole paragraphs, but phrases and words. I've seen texts where it's almost like students bought highlighters by the case and used it to mark off the words that their eyes had passed over. Sort of like boldfacing an entire chapter ... The result is that highlighting means nothing even though great importance is ascribed to it.

Even better, a good student makes notes in the margin, showing that there's some interaction with the text. Highlighting is just dragging a marker over the text. No further mental engagement required for the process ... And often no further mental engagement is forthcoming.

I hate highlighters. But if I' confronted with a difficult text, I leave behind all kinds of marks and connections drawn between portions of the text, cross references, and even explanations, criticisms, and notes to self about what must be meant (even if it's unlikely) and things that cannot be meant.