Why Can’t You Remember Being a Baby?

Try to find your earliest memory. Most people land at about three and a half years old. Almost nobody finds anything before two.

That is strange. In those years you learned to walk, learned a language and learned to recognise faces. It is the steepest learning a human ever does, and none of it is in there.

The usual explanation is that a baby's brain is too undeveloped to make memories. That is wrong.

Babies do remember

A six-month-old recognises its mother. Tie a mobile to a baby's foot and it works out that kicking moves it. Come back two weeks later and it remembers.

So the memories are being made. Something happens to them afterwards.

Reason one: the index is being rebuilt

The hippocampus is the part of the brain that files memories. Think of it as the index, not the library. Lose the index and the books are still there, but none can be found.

In an infant, that index is being built while it is being used. New cells are added at a rate that never happens again, and adding them disturbs the memories already stored.

A memory is a pattern of connections. It is closer to a path worn across grass than a file in a drawer. Build a new road through the field and the old path becomes hard to find.

Researchers tested this in animals, both ways. Speeding up new cell growth in adults made old memories fade. Slowing it down in infants let memories survive that should have vanished.

Reason two: language changes the format

Before you have words, an experience is stored as sensation, image and feeling. After you have words, it is stored with a story around it. The story is the handle the memory is picked up by.

The adult can only read the second format. The early memories were not necessarily deleted. Nothing can open them.

In one study, young children were asked about an event soon afterwards and again years later. What they could recall later depended on the words they had known at the time.

The cut-off moves with culture

If this were only biology, the cut-off would be the same everywhere. It is not. Between cultures it moves by more than a year.

The difference follows how families talk to small children about the past. Where parents ask questions such as "who was there?" and "how did it feel?", children build story memories earlier and keep them.

Neither style is better parenting. But it shows that remembering is partly a skill. You were taught how to remember by being asked to.

What does survive

There are two memory systems.

• Episodic memory stores events, in order, with you in them. It is the one you can describe.
• Procedural memory stores how, not what: walking, the grammar of your first language, how faces work.

Almost everything you learned before three lives in the second system. You use it every hour and cannot remember learning any of it.

Emotional learning is similar. The part of the brain that learns fear matures earlier than the part that files the story. So an adult can flinch at a smell and have no idea why.

Your earliest memory is probably rebuilt

Picture your earliest clear memory. Are you in it, seen from the outside, like watching a small child?

That is impossible as a recording. You were behind your own eyes at the time. It is the mark of a memory assembled from photographs, family stories and a real fragment.

Memory is not playback. It is rebuilt every time you look at it, using the version you last looked at. The memories you revisit most are often the furthest from what happened.

Why build a brain this way?

Nobody is certain. There are two good arguments.

• Early memories would be misleading. They record a world where everything was enormous and you could not walk.
• Those years were needed for something more valuable: building the machinery that all later memory runs on.

The short answer

You did not lose those years. You spent them building the thing that remembers everything else.