Reading with a Highlighter Is a Trap

Throughout our school years, we learn to read by highlighting and underlining. Exam-taking, in particular, cements the habit. Everyone has had the experience of busily underlining their way through a reading-comprehension section. And once the college entrance exams are over, the chances to actually improve our reading skills dry up.

A good reading strategy is one that internalizes the material and makes it your own. So you can't just highlight or underline and call it a day. Summarizing in your own words is fine, but far better is to internalize the material and rewrite it to fit your own situation and context. That's why we should be writing reading notes, or reading cards. It's the same thing as writing reference notes (literature notes) in Zettelkasten.

Highlighting and underlining don't internalize what you read. Worse, they can give you the feeling that you've understood something completely.¹ But highlights and underlines fade from memory over time. Most of you have probably experienced this already.

They also can't serve as reference material for developing an idea. That's because you never revised the content to bring it closer to your own thinking, and you never gathered it all in one place either. So highlights and underlines make it hard to consult that source later. You vaguely remember something, sure — but figuring out which book the related thought came from is the hard part.