Online education is now a major part of college and university learning. These digital courses offer great convenience and flexibility. But many students struggle to stay focused during online lectures. They often let their minds wander and typically do not perform as well as students in traditional classrooms. 

Our research offers a simple but powerful solution: insert short quizzes throughout the lecture. We call this approach interpolated retrieval practice. Here's how it works: instead of watching a 20-minute lecture straight through, students watch it in four shorter segments and take a brief quiz containing just four brief questions after each segment. Research has shown that these quick quizzes not only help students remember what they have learned, but also to better learn new information that follows each quiz. This approach is easy to implement, cost-effective, and can tackle concentration problems often seen in online education.

But there is a catch, nearly all of previous studies were conducted in quiet, controlled lab environments. We wanted to know if these quick quizzes would actually work in the messy context of online learning in the real world.

Can Retrieval Practice Boost Learning for Community College Students?

Another important goal of our project was to see if this quiz technique would help community college students. Previous studies have focused almost exclusively on university students and rarely included community college students - even though they make up half of the online students in the U.S. Because these students represent such a large and growing portion of online learners, we wanted to specifically determine if the quiz technique would improve their learning outcomes, too. To this end, we recruited over 700 students from five community colleges as well as students from two public universities. Securing collaborations with community college was a challenge, and we are incredibly grateful to our community colleges (e.g., American River College, Columbus State Community College, Cuyahoga Community College, Des Moines Area Community College, Iowa Central Community College, and Mohawk College) for their support of scientific research.

Would Retrieval Practice Enhance Learning with the Presence of Distractors?

Lastly, we wanted to know if quizzes could still enhance learning when students face various distractors. In real life, students are surrounded by all kinds of distractions. They might receive notifications on their phones, watch TikTok videos, or browse the internet.

To systematically study this effect, we divided participants into three groups to examine different distraction levels as shown below: (1) A control group who watched online lectures without any distractors, (2) a medium-distractor group who viewed lectures while being shown funny memes, and (3) a strong-distractor group who watched lectures while being shown TikTok videos (without sound). This approach allowed us to measure how effective the quiz technique remains under increasingly distracting conditions that mirror real-world online classes.

Our Research Design: Comparing interpolated quiz vs. interpolated review

In our study, participants watched a 20-minute lecture divided into four segments. To make our study resemble real-world online learning, participants completed it at their own convenience, choosing when and where to do so. We assigned participants to one of two learning conditions, which they completed after watching each of the first three lecture segments: (1) An interpolated quiz condition, where participants took brief quizzes and (2) an interpolated review condition, where participants studied review slides.

We combined these learning approaches with the three distractor levels mentioned earlier. This created a 2×3 study design with six different participant groups. All participants watched the fourth lecture segment with no interruptions and then took a test on that final segment. To measure long-term learning benefits, participants took a comprehensive test covering the entire lecture one day later.

Short Quizzes Improve Online Learning for Both Community and University Students

We found that students who took brief quizzes following each segment performed significantly better on both the fourth segment and comprehensive tests than those who studied review slides. Importantly, this finding held true for both community college and university students, which suggests that inserting quizzes can effectively boost online learning for a diverse student body. Although answering quiz questions did not reduce mind wandering, the benefit of quizzing on learning was supported by a broader index of task engagement.

We also uncovered an unexpected result about distractors. The level of distractor did not impact students’ test performance. But here’s where it gets intriguing for students who reviewed slides: those who watched the lecture in the presence of strong distractors (TikTok videos) actually performed better than those in a no-distractor condition. Why might this happen? We believe that the TikTok distractors might have prevented these students from becoming bored with and therefore disengaged from the lecture. The silent TikTok videos might have paradoxically helped these students stay more alert and pay at least some attention to the lecture rather than zoning out.

Lastly, recruiting diverse groups of students across several community colleges allowed us to see if interpolated quizzing can reduce achievement gaps. Our data provided preliminary evidence that it did, although these results await future replications and extensions.

Future Directions

Our current study had some limitations that open up exciting paths for future research. Students could ignore the distractors in our experiment. We are curious about what would happen with more intrusive distractions—like getting messages from friends during a lecture. Would interpolated quizzes still promote learning in these situations?

Another point is that our distractors were completely silent. This meant students could still hear the lecture clearly, no matter what was popping up on their screen. But what if the distractors had sound? Although many important questions remain, our experiment has shown that inserting brief quizzes can promote learning despite the array of distractions students face in messy, real-world online learning environments.