The average young person arriving in a classroom, training room, or onboarding session today has already watched more video than any generation in history. They've learned to tie knots, solve equations, fix bikes, and understand global politics from platforms like YouTube. By the time they show up, they're fluent in visual learning in a way their teachers often aren't.

Gen Z (ages 14 to 29) were raised inside an ecosystem that made visual learning the default.

• When surveyed by Pearson in 2018, 59% of Gen Z named YouTube as a preferred way to learn, compared with 55% of Millennials. Preference for printed books moved in the opposite direction: only 47% of Gen Z named books, down from 60% of Millennials. (Pearson, 2018)

• When Gen Z and Millennials view the same visual content, eye-tracking shows Gen Z looks more actively (more eye movements) and stays focused on images and headlines, while Millennials scan more broadly. (Frontiers in Virtual Reality, 2026)

If you're designing learning programs for people under 30, the question isn't whether to use visuals. It's whether the ones you're using are earning their place.

What pictures actually do

The evidence that visuals help learning is about as strong as evidence gets in education research. A 2022 meta-analysis by Noetel and colleagues, published in Review of Educational Research, pulled together 29 systematic reviews covering 1,189 studies and 78,177 participants. They identified 11 multimedia design principles with significant, positive effects on learning. The biggest gains came from simple things: adding subtitles to videos for second-language learners, putting labels right next to the diagrams they describe (rather than on a separate slide), and using arrows, highlights, or bold text to point learners toward what matters most.

Why do these principles work? Because of how the brain is built. Research on dual coding, developed by cognitive psychologist Allan Paivio and built on by decades of follow-up studies, shows that we process information through two separate channels: one for words, one for images. Each channel has limited capacity. When we use them together well, we effectively double the bandwidth available for learning. When we overload one channel or waste the other, learning suffers.

When visuals backfire

Here's the part that rarely makes it into design conversations. Irrelevant images don't just fail to help. They actively hinder learning.

There's a famous psychology experiment that illustrates the principle at work. In Simons and Chabris's selective attention test, viewers are asked to count basketball passes between players in white shirts. Halfway through, a person in a gorilla suit walks into frame, thumps their chest, and walks off. Roughly half of viewers miss it entirely.

Attention is finite. When it's spent on one thing, it isn't available for anything else. That's the same dynamic at work every time an irrelevant image sits on a learning slide. 

Electroencephalogram (EEG) and eye-tracking studies show decorative images raise cognitive load: the brain is working harder to filter out the noise. A 2022 study found that decorative pictures "increase mental processing demands in multimedia materials" but "despite increased mental processing demands learning outcomes are not altered." A follow-up 2023 EEG study on emotional decorative pictures found the same pattern: physiological cognitive load went up, test scores didn't change.

Six principles that actually work

Richard Mayer's Cognitive Theory of Multimedia Learning (CTML) highlights important principles related to visual learning.  Mayer developed and empirically tested these principles (along with several others) across more than 200 experimental studies over three decades. They're collectively known as "Mayer's Principles" or "Mayer's multimedia design principles." These principles include:

• Multimedia: words plus relevant pictures beat words alone.

• Contiguity: place labels right next to the parts of the image they describe, not in a caption below or on the next slide.

• Signaling: use arrows, highlights, bold text, or colour to point learners to the part that matters most.

• Segmenting: let learners move through complex content one step at a time, at their own pace, rather than hitting them with everything at once.

• Coherence: remove anything that doesn't serve the learning objective. Decorative images, background music, fun-but-irrelevant stories.

• Redundancy: if you're narrating over a visual, don't also put the full narration on screen as text. The brain tries to process both at once and ends up doing neither well.

The one question

Before adding any image to a workshop slide, module, course, or training video, ask this:

Does this help the learner understand, or does it just make the material look better?

If it's the second one, cut it. A plain slide with a relevant diagram beats a beautiful slide with an irrelevant photo. 

A few ideas worth exploring

In our work designing youth programs, these are the ideas we find most interesting to think about:

• More visuals may not be the direction of travel. Many predictions assume richer media, more animation, more video. The opposite is also plausible: fewer, better-chosen visuals, supported by tools that help strip out decorative noise. The real bottleneck is attention, not production.

• "Engagement" is an imperfect measure. A learner who watches a slick video to the end has not necessarily learned anything. Engagement and comprehension are different variables, and engagement is simply the easier one to track.

• Generative AI will soon flood us with on-demand images. Whether that's good for learning is an open question. When visuals are cheap and plentiful, it becomes easier to add them without pausing to ask whether each one earns its place. The skill of removal may matter more than the skill of creation.

• Visual design effort often flows to the wrong end of the process. Making materials look professional to the commissioner and making them effective for the learner are two different briefs. Both matter. 

Conclusion

Learning happens when attention lands on the right thing for long enough to make sense of it. Everything in a well-designed visual serves that moment. Everything in a poorly designed one competes with it.

So the question is never whether learners are engaged or whether the material looks polished. It's whether each image on the page is helping a specific idea take hold. When visuals earn their place, they do something words alone cannot. When they don't, they quietly take attention away from the very thing the learner came to understand.

The job is to know the difference, and to design accordingly.