A note on how the brain actually works — written for every parent who has watched their child study for hours and remember almost nothing.
Ask your child tonight what they studied in school today. Then ask them what they remember about it. The gap between those two answers — and there will be a gap — is not a problem with your child. It is a description of how the brain works, and how school mostly ignores it.
In April this year, I sat at the back of a classroom in Chennai. Thirteen students. Five teachers. One hour. What I watched happen in that room changed how clearly I can now explain something I have believed for three years but never said simply enough.
This essay is my attempt to say it simply.
The biology of forgetting
In 1885, a German psychologist named Hermann Ebbinghaus spent months memorising meaningless syllables and then testing himself at intervals to see how much he retained. What he found became one of the most replicated results in cognitive science: without any active effort to hold onto information, we forget roughly 70% of it within 24 hours. By the end of a week, close to 90% is gone.
This is called the forgetting curve, and it is not a flaw in human memory. It is a feature. The brain is an extraordinarily efficient machine. It does not store everything — it stores what it has been given a reason to keep. Information that arrives passively — read from a textbook, heard from a teacher, copied into a notebook — is treated by the brain as low priority. It enters what researchers call working memory: a temporary holding space, roughly equivalent to the RAM in your computer. If nothing reinforces it, it is cleared.
Long-term memory is different. It is built through consolidation — a biological process in which the hippocampus replays and transfers information to the cortex for permanent storage. Consolidation requires one of three things: strong emotion, active retrieval, or meaningful use. Listening to a lecture produces almost none of these. Doing something — building, deciding, explaining, making — produces all three.
This is not a controversial finding. It is textbook neuroscience. What is extraordinary is how consistently school is designed as though it were not true.
What actually sticks — and why
There is a phenomenon in cognitive psychology called the generation effect. When you produce information yourself — recall it, construct it, say it aloud, write it in your own words — you retain it significantly better than if you simply read or hear it. The act of generating creates a richer memory trace. More neural pathways are involved. The brain works harder, and that work is the learning.
Related to this is what researchers call embodied cognition: the idea that learning is not purely a mental event. The body is involved. When a child manipulates an object, performs a gesture, or moves through a physical sequence, they create motor-memory alongside conceptual memory. Two encoding pathways are better than one. This is why you can still ride a bicycle after twenty years of not trying, even if you cannot remember a word from the Biology textbook you studied the same week you first learned.
And then there is the role of curiosity. Dopamine — the brain’s reward neurotransmitter — is released not just when we get something right, but when we are in a state of genuine inquiry, actively trying to figure something out. Dopamine enhances the encoding of information. A child who is curious is chemically primed to remember. A child who is bored is not. Boredom is not a moral failing; it is the brain’s signal that there is nothing here worth the metabolic cost of memory formation.
Put these three things together and you arrive at a simple principle: the brain learns best when it acts, when the body is involved, and when genuine curiosity is present. Passive sitting, passive reading, and passive listening are three of the least effective ways to build durable knowledge. And they are the foundation of almost every classroom in India.
What we saw in Chennai
On 16 April 2026, we ran the first pilot of Karkei’s SPARK-based Heart Module at The Rajavva Academy in Chennai. Thirteen Grade 10 students. Five teachers with between 7 and 18 years of classroom experience, sitting at the back. One ten-minute interactive session, preceded and followed by hand-written surveys and a short diagnostic.
SPARK is the internal design framework we use at Karkei. It stands for Sensorial, Participative, Authentic, Relevant, Kinaesthetic. Each letter is a test we apply to every learning experience we build. Does it engage more than one sense? Does the child act rather than watch? Is the content grounded in something real? Does it connect to their own world? Does the body move? These five criteria map, almost exactly, onto the neuroscientific conditions for memory consolidation. We did not invent them — we simply built an engineering framework around what the research has been saying for decades.
In the session, students used gesture-based AR to interact with a three-dimensional model of the human heart. They could rotate it, trigger the pumping cycle, follow the path of oxygenated and deoxygenated blood. They were not watching a video of someone else doing this. Their own hands were moving. Their own gestures were driving the visualisation. The heart — a concept most of them had read about for years without once seeing it in three dimensions — was suddenly something they were holding.
Here is what we measured. Mean self-reported understanding of how the heart works rose from 3.1 out of 5 to 4.1 out of 5 in a single session — a full one-point lift. When we asked every student whether they would want more of their subjects taught this way, all eleven who completed the diagnostic said yes. Seven said yes for every subject. Four said yes for Science and Biology specifically.
The teacher data was, to me, the more interesting signal. Five teachers observed the session. Five out of five said they would recommend Karkei to colleagues. Their mean rating of observed student engagement, compared to a typical Biology class, was 4.6 out of 5. And every single teacher — without exception — noted that students who usually do not engage came back into the room during this session.
I want to sit with that last point. Teachers with a combined total of over sixty years of classroom experience, watching a room of children they know well, all said the same thing: the ones who are normally absent — physically present but mentally elsewhere — were present.
The brain was given something to do. So it did something.
The student who gave us 1 out of 5
One student in the pilot rated her comfort with the Karkei controls at 1 out of 5. Her focus rating: 2. Her overall experience rating: 2. She wrote, bluntly, that the controls needed to be changed. By almost every measure on our post-pilot survey, she had the worst experience in the room.
She also had the largest knowledge gain.
She came in with the lowest score on our baseline diagnostic about heart anatomy. She left with the largest objective correction of a factual misconception. Something in the session got through the friction of a gesture interface that wasn’t working well for her. The content — a three-dimensional, animated, colour-coded representation of blood flow — did its job even when the interaction layer was failing her.
I have thought about this student a great deal since April. She is not, as I said when I first wrote about her, an inspirational story. She is a data point about how learning actually works. The brain will grab at concrete, real, visual information even in uncomfortable conditions. Comfort and engagement are not the same thing as retention. A child can dislike an experience and still learn from it, if the experience is real enough, visible enough, grounded enough in how the brain encodes information.
What she also tells us is something parents already know intuitively but rarely hear said plainly: your child’s struggle in school is almost never about intelligence. It is almost always about design. The content exists. The child’s brain is ready to receive it. The gap is in whether the delivery method matches how consolidation actually works.
What this means for your child
I am not going to tell you to change schools. Most families cannot, and most alternatives are not substantially different at the level of teaching method. What I want to offer instead is a way of seeing what is happening — because understanding the biology makes the frustration more productive and the interventions more targeted.
The most powerful thing a parent can do, given what we know about the generation effect, is to ask the child to teach the content back to you. Not quiz them with questions. Ask them to explain it, as if you know nothing. This is called the Feynman technique — named after the physicist who used it obsessively — and it works because the act of explaining forces the brain to retrieve, organise, and reconstruct information. Reconstruction is consolidation. Consolidation is memory.
The second thing is to notice where your child comes alive. Every child has subjects, activities, moments where the boredom lifts. That lift is not a mood. It is a biological event — curiosity, dopamine, the conditions for learning are present. Whatever produces that state in your child is not a distraction from their education. It is the closest thing to the conditions the brain actually needs.
The third is patience with the system, alongside clarity about what the system is not designed to do. Indian schools — and I say this as someone building inside them, not criticising from outside — are mostly designed to produce students who can answer questions on an exam. That is a legitimate and important goal. It is not the same goal as producing students who have internalised knowledge in ways that will be useful to them for the rest of their lives. The forgetting curve does not care about board exams. It runs on its own schedule.
Why I am building this
I have three daughters. I watch them study. I watch them forget. I watch them come alive in moments that have nothing to do with what is being marked in class. I am not angry about this — I understand the system and I do not think it is operated by people who do not care. But I am building Karkei because I am convinced, from the science and from what I saw in that classroom in April, that we can do better than the current design. Not by replacing the teacher. Not by gamifying everything until it is entertainment. But by building learning experiences that match how the brain actually consolidates what it encounters.
The session at The Rajavva Academy lasted ten minutes. The students had been studying the heart, in the conventional way, for years. In ten minutes of doing something with the content — rather than reading about it — their self-reported understanding moved a full point on a five-point scale. Every teacher in the room saw students who normally switch off, switch on.
This is not a miracle. It is not a product advertisement. It is what happens when you stop designing for the exam and start designing for the brain.
The brain learns by doing. That is not a metaphor. It is biology.
— Elango Raghupathy
Founder, Karkei · Chennai · elango@karkei.com
Karkei is a Chennai-based company building SPARK-compliant experiential learning systems for Indian schools. Our Heart Module is currently in classroom pilots across Tamil Nadu. If you teach, lead a school, or are a parent who wants to know more, write to us at vanakkam@karkei.in.