What Teachers Can Learn from Contagious
Assuming that a genuinely useful idea will spread among students on its own because it's true and important is the specific trap Contagious names, and it's an easy one to fall into when the value of the idea seems obvious to you.
The whole book, compressed
This edition works through 4 core lessons — take them one at a time, not all at once.
What's different for your conditions
Tap whichever ones sound like you. Nothing here is sent or saved — it's just for your own noticing.
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The core lessons, applied to you
Give students something that makes them look good for sharing it
Students repeat ideas that make them look clever or interesting to a friend or family member, not ideas that are merely correct.
A teacher presents an accurate, well-organized explanation of a concept, and students who understood it fine never mention it outside class, because there's nothing in the framing that makes explaining it to someone else feel rewarding.
Identify one surprising or clever-sounding detail about a concept you're teaching, and lead with that detail instead of the formal definition.
Build the idea into things students already encounter regularly
An idea tied to something in a student's daily environment stays present far longer than one that only comes up during class time.
A teacher delivers a strong lesson, then finds students have forgotten the core idea within days because nothing in their daily life outside class reminds them of it.
Identify one everyday object or moment your students already encounter often, and find a natural way to connect the lesson to it.
Make students feel something specific, not just know a fact
Genuine engagement comes from an emotional reaction, not from information alone; a student who merely understands a fact has no real reason to bring it up outside class.
A teacher explains a concept thoroughly and accurately, and students can recite it on a test but never mention it to anyone else, because nothing about the lesson actually made them feel anything.
Identify the specific reaction (surprise, amusement, indignation) you want a concept to produce, and check whether your current explanation actually produces it.
Give the idea a visible, practical, and story-shaped form
A concept that students can visibly demonstrate to someone else, that gives them genuinely useful information to pass along, and that fits into a story they'd enjoy telling, spreads far more easily than one presented only as an abstract definition.
Covering required material and making a lesson memorable aren't opposites — a concept taught with a specific feeling and a shareable hook is usually retained better on the test too.
Name one thing, honestly
Is there a concept you teach well that students still never mention outside your classroom?
Good. Now look back at the "Try this" line under whichever lesson feels most connected to what you just wrote, and treat that as this week's actual assignment — not all 4 at once.
The practices from this edition
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Run this for seven days
Identify the specific reaction (surprise, amusement, indignation) you want a concept to produce, and check whether your current explanation actually produces it.