We often think how fast we learn something is a function of how smart we are. If your brain is soaking in material quickly, you're intelligent; if not, well, that doesn't say great things about your IQ. But science shows context and technique actually play a huge role in how fast we learn, and even small changes — like the format you use to read — can make a huge difference.

Intelligence Isn't the Problem

Audiobooks have plenty of advantages; you can enjoy them anywhere, even in the car, and not printing books saves trees. Less fluent readers also often find them more accessible and absorbing. But according to the latest research, if your goal isn't to pass the time in traffic or on the treadmill, but instead to learn something difficult, you should definitely choose a physical book.

In a recent opinion piece in the New York Times, psychology professor Daniel T. Willingham cited a 2010 study where 48 students either read or listened to an article about child psychology. Although the students spent the same amount of time with their material and did about the same number of distracting activities while they absorbed the information, they scored very differently on a 10-item quiz later: On average, the readers scored 81 percent whereas the listeners scored 59 percent.

The difference between 81 percent and 59 percent is the difference between a B- and an F, so that's not small potatoes. Why does listening versus reading material have such a massive impact on learning?

Willingham explains two factors are likely at play. First, most of us read more slowly than we listen (especially when pausing and rereading is factored in), and when you're trying to absorb new information, slower tends to be better. "About 10 to 15 percent of eye movements during reading are actually regressive — meaning [the eyes are] going back and re-checking," he explained to TIME. "This happens very quickly, and it's sort of seamlessly stitched into the process of reading a sentence."

Second, books offer visual cues that help our brains organize and understand new information. Things like chapter breaks, subheadings, and lists aid us in making sense of the material and understanding how it fits together. You lose all that when you go the audio route.

The bottom line is simple: Don't feel guilty about passing your commute with an audiobook — that's certainly preferable to spending it swearing at some jerk who just cut you off. However, be aware of audio's limitations when it comes to studying, and seriously consider opting for good old-fashioned reading instead.

What About E-Readers?

In fact, you might want to go even one more step more old fashioned still and actually opt for a physical book over your iPad or Kindle. Another recent study out of Norway found that those who read a story from a book remembered details and the order of events better than those who read in on a screen. Yet more research showed those using screens read faster and were more confident in their comprehension, but actually performed worse on a quiz after. This could be due to Willingham's second point: e-readers give you some visual cues, but not as many as a paper book. It's not as easy to know how far along you are, for example.

This science isn't yet conclusive, but it appears that audio and print each have their place. If you want to get some light reading in during a commute or a workout, obviously opt for audio. But if you want to make it as easy as possible to learn something hard, you might want to try reading like it's 1999. Opt for the most old-fashioned option of all, a straight up paper book, and you might be surprised how fast you grasp the material.