Interactive Diagrams for Learning: How Tapping a Concept Changes Retention

A standard diagram is a picture. A labelled image. It shows you a concept — that is useful.

An interactive diagram is something different. It is a concept you can ask questions of. In Proglly, students tap any part of the diagram and receive an explanation of exactly that element — instantly, in plain language, at their level. Not the whole concept. Just the part they tapped. The one they chose.

Try it on the plant cell below. Tap any glowing dot.

When learners direct their own attention — choosing what to examine, asking questions rather than receiving answers — encoding is deeper and retrieval is stronger.

This is partly explained by elaborative interrogation: generating explanations for why something is true improves retention significantly (Woloshyn et al., 1992). Tapping a component and asking 'what does this do?' is elaborative interrogation made frictionless.

Mayer's (2009) work on multimedia learning is also consistent: learners build more durable understanding when they actively select, organise, and integrate visual and verbal information — rather than receiving it in a pre-determined sequence.

The concept sounds simple. What is actually required: the diagram must be accurate enough to teach from — not decorative or approximate. The tappable regions must align with conceptual boundaries, not just geometric areas. The explanation on tap must be contextually aware. And it must work for any topic, at any level, with no human curation in the loop.

That last constraint is what made it genuinely hard. Three build iterations. Worth every hour.

The student Proglly is designed for is not the top 10% who are already succeeding. It is the student who has watched three YouTube revision videos and still cannot sit an exam confidently.

The one whose parents assume they are not trying, when what is actually happening is that the format is wrong. That student deserves learning that is visual, interactive, and engaging — the kind a private tutor would create, except on demand, for any topic, in their pocket.