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Revealing bullet points, graphs, and illustrations on a presentation slide one piece at a time as a teacher speaks can help students focus on the right information and remember more of a lesson, according to new research published in the Journal of Computer Assisted Learning. In an eye-tracking experiment with a recorded biology lecture, the step-by-step format drew learners’ eyes to relevant visuals faster and held their attention there longer than displaying the entire slide at once.
In a typical classroom or online lecture, students listen to an instructor’s spoken explanation while simultaneously reading text and interpreting diagrams on a screen. Processing spoken audio and visual slides at the same time taxes two separate channels in human working memory, which can increase cognitive load. Cognitive load refers to the total amount of mental effort being used in working memory at one time, and when a crowded slide overwhelms that capacity, comprehension tends to suffer.
To ease this mental bottleneck, the cognitive theory of multimedia learning outlines several principles for designing instruction with words and pictures. One is the segmenting principle, which involves breaking complex lesson material into smaller, manageable parts presented sequentially. Evidence from a 2019 meta-analysis of multimedia learning studies indicates that dividing lessons into bite-sized segments helps students understand and remember material better on average than continuous, unbroken presentations, even when the presentation itself sets the pace rather than the learner.
Multimedia instruction also benefits from guiding learners toward the right spot on a screen while the instructor speaks. Researchers call this visual cueing: using signals like highlights, arrows, or sudden appearances to steer a learner’s gaze. It works best alongside temporal contiguity, the principle that people connect spoken words and visuals most easily when they are presented at the same time. A 2008 study found that building up an illustration piece by piece as a narrator described each part, and changing the color of the part being discussed, helped learners better remember the diagram’s content.
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Coordinating these visual and spoken signals helps anchor attention where it is needed. Work from a 2019 series of three eye-tracking experiments found that students spent more time looking at the relevant part of a graphic, and scored higher on tests, when a visual element turned red at the same moment the narrator stressed it with a deeper voice, compared with no cues. These coordinated cues also produced better test scores than either cue alone or cues that were mismatched or out of sync.
Building on this research, first author Hikaru Ito and Hiroko Ichikawa, a professor in the Department of Applied Biological Science at the Graduate School of Science and Technology at the Tokyo University of Science in Chiba, Japan, tested a practical slide format they call cumulative presentation, which applies a similar step-by-step approach to slides mixing text, illustrations, and graphs. In a cumulative presentation, individual elements are revealed one by one on a single slide in sync with a teacher’s narration, remaining on screen as new pieces are added so students can see how the whole topic fits together.
The authors reasoned that because each newly appearing item naturally catches the eye as the teacher explains it, this approach combines segmenting, visual cueing, and synchronized timing using standard software like PowerPoint.
“The idea came from our first author, who was preparing to become a high school science teacher and wanted to learn something they could put to use in the classroom,” Ichikawa told PsyPost. “Teachers often reveal parts of a slide as they explain them, leaving earlier parts visible. As far as we knew, no one had used eye tracking to measure how this practice guides students’ attention, so we wanted to see where students looked and whether the way we presented the slides affected what they learned.”
To test how this format affects eye movements and learning, the researchers recruited 40 Japanese university students majoring in science and engineering. The sample included 19 men and 21 women aged 18 to 24, with an average age of about 21 years. Based on large effects observed in earlier eye-tracking studies, the authors calculated beforehand that 18 participants per group would be enough to reliably detect a large difference between groups.
Participants were randomly assigned in equal numbers to either a cumulative presentation group or a whole-slide presentation group. Before the lesson, everyone took a 12-minute pre-test to measure baseline knowledge of the biology material. The pre-test and the post-test administered after the lesson were identical, containing multiple-choice questions, graph interpretation tasks, and short open-ended questions worth up to 20 points.
Next, each participant sat roughly 60 centimeters from a 24-inch monitor fitted with an eye-tracking camera that recorded eye movements 60 times per second. After calibrating the tracker, students watched a 20-minute recorded biology slideshow lesson on interactions between populations, covering predator-prey relationships, symbiosis, parasitism, and interspecies competition across seven slides. Participants were asked to keep their eyes on the monitor and not take notes.
Both groups heard the same spoken narration and saw the same slide content combining text, illustrations, and line graphs. In the cumulative group, each text point, illustration, or graph appeared on the slide at the exact moment the instructor began explaining it and remained visible until the slide ended. In the whole-slide group, all elements on a slide were visible from the moment that slide appeared.
To measure visual attention, the authors defined 32 target zones across the five main content slides corresponding to specific pieces of text and graphics. They tracked how quickly students first looked at a target zone once the teacher began discussing it, along with the total time their gaze rested on each zone from the moment the teacher began discussing it until the slide changed. Immediately after the video, students took the 12-minute post-test and rated test difficulty, lesson difficulty, and lesson understandability on a five-point scale.
Test scores and questionnaire ratings were analyzed for all 40 participants, while eye-tracking data were analyzed for 36 participants after excluding four students whose eye movements were captured for less than 75 percent of the lesson. On the pre-test, the difference in baseline knowledge between the cumulative group, which averaged 11.35 out of 20, and the whole-slide group, which averaged 12.55, was not statistically significant.
On the post-test after the lesson, students in the cumulative group scored higher than those in the whole-slide group, averaging 17.70 points out of 20 compared to 16.70 points, even as both groups approached the 20-point ceiling. Because the cumulative group started slightly lower on the pre-test and finished higher, its average gain was about 6.4 points compared to 4.2 points in the whole-slide group. The post-test difference was medium-sized (an effect size of 0.49), smaller than the large difference (0.8) the study was designed to detect, and was still statistically significant, though narrowly.
The eye-tracking recordings showed much larger differences in how students allocated their visual attention. When the instructor began explaining a specific item, students in the cumulative group looked at the matching visual element after an average of about 1 second, whereas students in the whole-slide group took an average of 5.75 seconds to look at the relevant spot. Over the 20-minute lesson, students in the cumulative group also spent substantially more time looking at the visual elements matching the teacher’s narration, averaging about 442 seconds (roughly 7.4 minutes) compared to about 326 seconds (5.4 minutes) in the whole-slide group.
These differences were not driven by overall screen engagement, as total time spent looking anywhere on the monitor was about 802 seconds (13.4 minutes) in the cumulative group and about 791 seconds (13.2 minutes) in the whole-slide group, a difference that was not statistically significant. When the researchers totaled the time whole-slide students spent looking at the target visuals across the entire duration of each slide, including before the teacher mentioned them, that figure reached about 487 seconds (8.1 minutes), and the difference from the cumulative group’s 442 seconds was not statistically significant.
In the authors’ reading, simply looking at a slide longer does not automatically improve learning. The researchers suggest that when an entire slide is presented at once, students may have to expend extra mental effort searching the screen to find what the teacher is discussing, which could make it harder to connect the spoken explanation with the visuals. Revealing elements incrementally, the authors propose, cuts down on that search.
Ichikawa said the findings bear on a habit many teachers already have. “To me, that gives experimental support to something teachers have learned through experience,” she added. “It also makes me curious about other small choices teachers make when designing slides. Some may help students learn in ways we have yet to measure.”
At the same time, the presentation format did not measurably change how difficult students felt the material was. Group differences in self-reported test difficulty, lesson difficulty, and understandability were not statistically significant. The authors point out that earlier visual cueing studies found a similar pattern, suggesting that multimedia design can improve learning and visual attention even when students do not consciously feel that the lesson was easier.
There are a few things to keep in mind when interpreting these results. Because cumulative presentation bundles segmenting, visual cueing, and synchronized timing into a single format, the experiment cannot separate which feature, or which combination of features, produced the benefits. The findings also rest on a single 20-minute recorded biology lesson on one topic. And because the post-test came immediately afterward and repeated the pre-test questions, it measured short-term retention rather than long-term memory or whether students could apply the concepts to new problems.
With only 40 science and engineering students from a single university (36 with usable eye-tracking data) and a post-test difference that only narrowly cleared statistical significance, the learning result in particular needs replication. Participants also watched the video in a laboratory and were instructed not to take notes, whereas real classrooms involve larger groups, wider age ranges, and note-taking, which could change where students look during a lecture. In addition, the brief questionnaire used to measure perceived difficulty was limited because its questions did not hang together well as a single measure.
The authors suggest future studies should apply standardized cognitive load questionnaires and test how cumulative slides work across different combinations of text, illustrations, and graphs in live classrooms.
Ichikawa also noted that a step-by-step slide format may not benefit every learner equally. “Students who already know the material may be ready to move on while the teacher is still explaining, so revealing information gradually could slow them down,” she explained. “I’d also like to know whether students who have the skills or the motivation to explore a graph on their own might learn more if they could see the whole graph from the start. We’d like to test those possibilities in future work.”
The study, “Cumulative Presentation Enhances Learning Outcomes by Directing Learners’ Visual Attention,” was authored by Hikaru Ito and Hiroko Ichikawa.
