I stopped feeling like a fraud. I actually understand the calc chapter I've been faking my way through for eight weeks.
enrolling · fall betafor students who feel weird about using AI
Every other AI is making you dumber. Get your brain back.
Brainback is a study tutor that refuses to hand you the answer. It uses Socratic questioning, hint ladders, and retrieval practice — so the concept actually lands in your head, not just on the assignment.
Free during beta · no credit card · or join the waitlist for updates
rolling beta · new seats weeklyfree during betano credit card
try it right now
Ask it anything. Watch it refuse to hand you the answer.
Pre-canned demo of the tutor engine. Type a real question or pick a sample — you’ll get one correction, one guiding question, and a redacted “answer” you don’t get to have yet.
“It won’t just do it for you” sounds annoying until you’ve had a semester where it did.
live demo · brainback tutor
Active recall
Spaced repetition
Socratic method
Desirable difficulty
Retrieval practice
Metacognition
Bloom's taxonomy
Interleaving
the problem
Two students. Same class. One rents their thinking. One owns it. Watch what happens.
This is the shape of the last two years of college — playing out in every dorm, in real time. Scroll.
01week 1
They start the same way.
Both students open the syllabus, both start the first problem set. One types the problem into an answer machine. One types it into Brainback.
Student A — with the answer machinehw: A
"'It just gives me the solution. This is easy.'"
concepts actually retained
Student B — with Brainbackhw: B+
"'It won't give me the answer. It made me try first. Weird.'"
concepts actually retained
02weeks 2–5
One rides the machine. One does the reps.
Homework rolls out. Student A copies. Student B attempts, gets a nudge, tries again, gets scored, sees a card in their recall queue three days later.
Ahw: A
"'12 hours a week saved. Grades great.'"
concepts actually retained
Bhw: A-
"'Slower on the homework. Concepts stick, though.'"
concepts actually retained
03midterm
The exam happens.
Same room. Same paper. No copy field. A cannot recognize a single problem — the machine did the recognizing every week. B has seen these exact concepts in their spaced-recall queue five times.
A · midtermmidterm: 62
"'I studied by re-reading the solutions. Why doesn't it feel familiar?'"
concepts actually retained
B · midtermmidterm: 84
"'The exam feels like homework.'"
concepts actually retained
04final
The gap becomes the semester.
By the final, A's grade is falling and A doesn't know how to study — every previous session was outsourced. B walks in and writes it out. This is the compound. This is what the tool was designed to prevent.
this is the whole thesis of the product
A · finalfinal: 41
"'I don't know how to learn anymore.'"
concepts actually retained
B · finalfinal: 91
"'Second-highest in the class.'"
concepts actually retained
the whole semesterexam-score line
the learning science
None of this is a theory. It’s a hundred years of psychology, made operable.
Ebbinghaus, 1885. Bjork, 1994. Roediger & Karpicke, 2006. Every choice in Brainback is downstream of a paper. Drag the slider below to feel one of them.
the forgetting curve
Retention halves in a day. Then again. Then again. Unless you interrupt it.
A single re-encounter at the right moment resets the whole curve — and each successful review stretches the next interval. That’s the entire logic of Brainback’s recall queue.
each purple dot is a card returning to your queue
bloom’s taxonomy
Answer machines optimize for the bottom rung. We aim at the top.
“Remember” is where a copy-paste solution lives. “Create” is where a semester of understanding compounds. Brainback’s attempt-gate, hint ladder, and explain-back all live above the fold on this pyramid.
spaced-repetition schedule · SM-2
actually try it
Take a three-question quiz. Feel what your brain does when nothing hands it the answer.
This is retrieval practice. It’s the single most well-replicated finding in learning science. You’re about to do it in your browser, on the marketing site for a product that is literally built around it.
retrieval practice · question 1 of 3
calc
State the chain rule in one sentence, in your own words.
Hint available. Try first — it counts more.
Score yourself against the reference — honestly.
Show reference answer
The derivative of f(g(x)) is f'(g(x)) · g'(x) — you multiply the outside-rate by the inside-rate.
the hint ladder
Climb five rungs. The last one stays yours. Try it.
This is a real Brainback problem with real hint ladder text. Click to unlock each rung — every one costs points. Level 6 is the answer. It doesn’t exist. Not for you, not for anyone.
Related rates · problem set 4, Q7brain points spent · 0
A ladder 10 ft long leans against a wall. The bottom slides away from the wall at 2 ft/s. How fast is the top sliding down when the bottom is 6 ft from the wall?
- rung 6 · the answerunavailable
each rung takes you closer — none of them takes you there
side by side
Answer machines ship answers. Brainback ships questions.
Pick a subject. See the same student ask the same question, and watch the two tools respond in parallel. Everything below is verbatim from actual sessions.
the student asks
What's dy/dx if y = sin(x²)?
answer machine ships the answer
Let u = x². Then y = sin(u). Differentiating: dy/du = cos(u) and du/dx = 2x. By the chain rule: dy/dx = cos(x²) · 2x = 2x·cos(x²). (Copy this. Paste into your assignment.)
You copy. You submit. You see it again on the midterm — and you don’t recognize it.
brainback ships the question
You're right to reach for the chain rule.
You want me to say dy/dx = 2x·cos(x²) — I won’t.
Instead: Before I say anything: the chain rule says the derivative of f(g(x)) is which two things multiplied together? Say them in order.
You attempt. It grades. The concept lands. Next problem gets easier.
Same student. Same question. Two entirely different definitions of “help.”
how it works
Three steps. In this order. No skipping.
01
You attempt first.
Type a real start — at least twenty characters, or a photo of your work. The tutor is server-locked until you do.
02
It hands back a question, not a solution.
One correction, one guiding question. Stuck? The hint ladder gives you the next rung — never the final step.
03
You lock it in with retrieval.
Explain the concept back in your own words. Errors become spaced-repetition cards. The Brain score tracks the compound.
beta students
What people say after the first two weeks.
FAQ
Fair questions. Straight answers.
No. A system prompt drifts inside a single conversation — ChatGPT will happily hand you the answer if you rephrase the ask three times. Brainback enforces the refusal server-side, runs an output guard on every reply with a second model, and has no toggle a jailbreak could flip. The rule is architecture, not instruction.
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Take back the semester you actually meant to have.
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