If you’ve ever watched a videotaped lecture or speech online, you’ve probably experienced this phenomenon:

You cue up the video with every intention of paying close and conscientious attention. As the video plays on, however, you find your mind drifting—to a conversation you had earlier in the day, to the list of things you need to accomplish before tomorrow. Seeing as you’re already at your computer, you may even feel the urge to take a peek at your email, or your Facebook feed, or your Twitter stream . . . and by now, that voice droning in the background has been all but tuned out.

If you’re watching the video for your own edification, this is no big deal. But for students taking courses online, such inattention undermines their comprehension and recall of important academic material, as well as wasting a lot of their time. “Some students I’ve talked to say that it takes them as long as four hours to get through an hour-long online lecture because they’re trying to combat all the distractions around them,” says researcher Karl Szpunar in an article in the Harvard Gazette.

While a postdoctoral fellow in psychology at Harvard, Szpunar and his mentor, Harvard professor and memory expert Daniel Schacter, discovered a way to help students “efficiently extract the information they need” from online courses. The solution: tests.

Szpunar (now an assistant professor at the University of Illinois at Chicago) has demonstrated in a number of studies that “interpolated tests”—quiz questions embedded at intervals throughout a videotaped lecture, to which students are required to respond—leads students to better maintain their attention and to take more comprehensive notes, leaving them with improved understanding and recall of the material.

Szpunar and Scachter’s early studies revealed that the tendency to mind-wander during videotaped lectures was common: when prompted to report what they were thinking about, students admitted to not paying attention to the lecture about 40 percent of the time. The researchers experimented with different ways of maintaining students’ focus, and found that the interpolated quizzes worked best:

“It’s not sufficient for a lecture to be short or to break up a lecture [into segments],” Schacter said. “You need to have the testing. Just breaking it up and allowing [students] to do something else, even allowing them to re-study the material, does nothing to cut down on mind-wandering, and does nothing to improve final test performance. The testing is the critical component.”

It’s a matter of providing incentives for students to engage in a particular kind of mental activity, adds Szpunar:

“Whether it’s in the classroom or online, students typically don’t expect to have to summarize a lecture in a way that makes sense until much later on,” Szpunar explained. “But if we give them an incentive to do that every now and then, students are actually much more likely to set everything else aside, and decide they can get to that text after class, or they can worry about their other class later, and they’re able to absorb the material much better.”

Such interpolated tests can also work in a “live” classroom setting, say Szpunar and Schacter.

To me, this is yet another example of how tests can play roles in learning far beyond the one-dimensional assessment we use them for today. In some cases—as demonstrated by Szpunar and Schacter’s work—tests are the best way, bar none, to accomplish our educational objectives. This is what I’m getting at when I call this approach affirmative testing: done right, testing could represent not a negative influence on our schools, nor even a necessary evil, but an affirmatively positive force for student learning and growth.

I've created an e-course devoted to demonstrating how to implement affirmative testing, called Turn Testing Into Learning. You can try out a sample lesson by clickinghere; you can enroll in the course by clicking here.