It is quite literally an age-old debate. Are children born as a blank slate, or is everything already determined from the start? These are two positions that have alternated for centuries, usually in slightly more modern packaging, from behaviourism to insights from genetics. One emphasises environment and experience, the other focuses on disposition and biology.

Only… neither of them is entirely correct. Often, there is interaction, and nature and nurture reinforce each other. But a recent study in Nature Communications offers a different perspective.

Victor Vargas-Barroso and colleagues examine the development of the hippocampal memory system and reveal a picture that does not fit either of the classic frameworks. They do not find an empty beginning that is gradually filled. On the contrary. The network starts relatively dense and poorly structured, then becomes both sparser and more organised. Or, in their words: more a tabula plena than a tabula rasa. The idea itself is not new, but this study sharpens it by showing what that transition looks like in functional terms in the brain.

A different metaphor helps make this more concrete. Children are not born as blank slates, but as a messy, overstuffed bookcase. There is already a lot there. It is not in the right place, there are duplicates, and some books do not yet seem to belong anywhere. Some titles prove important, others less so. Development does not simply add new books. It also organises, selects and sometimes clears out.

This image maps closely onto what we see in the brain. Early in development, neurons form more connections, and those connections are stronger. In a sense, the system is overconnected. As children grow older, connections disappear, and the ones that remain become more selective and more functional. The brain does not simply grow fuller. It becomes more efficient and more targeted.

This process is not purely biologically predetermined. The study shows that experience helps organise these networks. What is often activated together gets strengthened. Yes, what fires together, wires together. What is rarely used fades away. The bookcase does not organise itself in isolation. It responds to what a child reads, repeats and uses.

You can see the same shift in how information is processed. In a young brain, a single strong signal can already trigger activity. Later on, multiple signals need to come together. The system shifts from rapid, broad activation to more integrated and selective processing. That makes it less sensitive to noise, but also more dependent on coherence and meaning.

All of this makes the classic debate less useful. This is not an argument for “everything is fixed at birth”. But neither is it a claim that “everything is malleable”. Instead, we see a system that starts with an abundance of possibilities and takes shape through experience by selecting, strengthening and pruning.

For education, this is far from a detail. We still often think in terms of adding: more knowledge, more content, more input. But if development also means that the brain constantly chooses what to retain and what to let go, then learning becomes something else. It is not only about what you offer, but also about what sticks, what is strengthened, and what gradually fades away.

That has implications. Repetition takes on a different meaning. It is not a dull extra, but a mechanism that determines what earns a stable place in that bookcase. Coherence becomes more important because isolated pieces of information are less likely to remain. And perhaps most importantly, what learners no longer use does recede into the background.