3 Reasons You Should Never Read Anything Important On A Screen

The results suggest that comprehension comes with reading the hard copy. So if you really want to master a subject, you may be better opting for a physical book than an e-book.

Here are a few theories on why.

1. Books aren't just visual, they're physical.

When trying to remember a piece of information, people recall where in a book the info appeared.

"We might recall that we passed the red farmhouse near the start of the trail before we started climbing uphill through the forest," writes Scientific American blogger Ferris Jabr. "[I]n a similar way, we remember that we read about Mr. Darcy rebuffing Elizabeth Bennett on the bottom of the left-hand page in one of the earlier chapters."

Similarly, physical sensations act as ways to anchor memory. The heft of the book in your hands - how weight shifts as you progress through the pages - acts as an inroad to durable learning.

2. Books are super customizable.

Underline, dog ear, scribble in the margin: these are all tactile ways of interacting with a book. They are also gestural, and gestures are linked with deep-level cognition.

As Brandon Keim notes at Wired, screen writing is much less tactile. Typing into that Kindle keyboard just doesn't have the same kinesthetic satisfaction that carving into the page with a pen provides. Some cognitive scientists think of that pen-on-paper interaction as a "comprehension prop," one that gets left out with e-readers.

We also need to think about the nature of learning.

Scientists scrutinizing study methods find that underlining or highlighting are basically useless for long-term recall. It's much more effective to quiz yourself on what you're reading. It's an easy argument, then, to say that the physical book is much more inviting of your inferences and objections to the text - so long as you've learned how to read actively.

3. Books send signals.

People think different things depending on conscious or unconscious prompts. The fancy-pants term is "cognitive goal."

Discover magazine has a great account:

A growing body of research shows that the same information can trigger very different thoughts depending on the cognitive goals that people have in mind. Readers can be instructed to create vivid imagery or to learn over time to make deeper inferences, both of which lead to better retention of the material they've read. And when readers are told to form an impression of people they're reading about rather than to read for the purpose of memorizing the text, they organize the information from the text less haphazardly and are able to recall more of it.

We get unconscious prompts, too. One study found that when people see the Apple logo, they're more creative then when the spot the same for IBM.

Let's carry that over to reading. Think of what a weighty book is implicitly telling you when you hold it in your hands: You're going to learn lots from me, but you're going to have to work hard. With those cues, you'll be primed to think harder.