How the Human Mind Grows
From infancy's peekaboo games to the turbulent teenage brain, human development follows a fascinating mental blueprint. Discover how children build their understanding of reality, learn to read other minds, and forge their adult identity. Walk away seeing everyday human behavior through a developmental lens.
Like Duolingo, but for How the Human Mind Grows. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
A short one: 12 levels across 2 sections, about 24 minutes end to end, roughly 5 days at five minutes a day. It moves through Understanding the Early Mind and Becoming a Social Self. It starts from scratch.
Free forever · No credit card · iPhone & Android

Key ideas in How the Human Mind Grows
- Looking time is used by developmental psychologists to measure surprise and expectation
- Infants stare significantly longer at events that violate basic physical expectations like solidity or gravity
- Basic core physics expectations appear months before babies can speak or walk
- Before roughly eight months, young infants do not hold mental representations of unobserved items
- Out of sight literally translates to out of existence in early developmental stages
- Peek-a-boo delights babies because the reappearance appears genuinely novel rather than predictable
- The prefrontal cortex, which governs emotional regulation and impulse control, is drastically underdeveloped in toddlers
- Emotional impulses and desires mature much faster than the brain systems required to soothe or suppress them
- Tantrums reflect an overload of an immature nervous system rather than deliberate misbehavior
- Children interpret new experiences by matching them to existing mental frameworks (schemas)
- When an experience directly clashes with an existing framework, the child must alter their categories (accommodation) to resolve the conflict
- Toddlers overextend regular grammar rules (adding '-ed' or '-s') to irregular words they have never heard spoken that way
- Adults do not model these specific errors, so imitation cannot explain them
- Errors like 'runned' or 'feets' prove the brain internalizes abstract generative rules rather than purely mimicking adult input
- Young toddlers assume other people like, see, and know the exact same things they do
- Egocentric choices at this age reflect genuine perspective blindness, not selfish intent or lack of empathy
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives How the Human Mind Grows the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
A baby watches a ball roll against a wall. Next, a ball seems to pass right through the solid wall. How will the baby react?
Get it right to open this lesson and 11 more in the app.
Where How the Human Mind Grows takes you
- 1
Understanding the Early Mind
- Seeing the World Through an Infant's Eyes
- Stepping Inside Other Minds
- 2
Becoming a Social Self
- The Attachment Blueprint
- The Teenage Brain Makeover
2 sections · 4 units · 12 levels. Built to play, not to enroll.
Tomo is in ChatGPT
Tomo is also a ChatGPT plugin: the same playable courses, built and played inside your chat.
Add Tomo to ChatGPT- What to ask
- “Make me a Tomo course on black holes.” “Turn this chat into a Tomo course.”
- What you get
- Quick questions with instant feedback, hearts and stars, ready to play in about a minute.
- Where it goes
- No sign-up to start. Connect your Tomo account and your streak carries on in the app.
You pick the voice
How the Human Mind Grows is taught in the Professor style: clear, structured, thorough. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
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Start How the Human Mind Grows today.
Download Tomo, search How the Human Mind Grows, and play your first lesson in under a minute.