# Infantile Amnesia: Why You Can't Remember Being a Baby

*Science & Technology · Priya Nair · 2026-10-12*

## TL;DR

Infantile amnesia is the near-universal inability of adults to recall events from roughly the first three years of life. It is generally attributed to the still-developing hippocampus, rapid early neurogenesis, and the slow maturation of brain networks that later support durable autobiographical memory.

## Key facts

- Infantile amnesia was described by Sigmund Freud in his 1905 work, who argued that adults rarely recall events from before roughly age three.
- Most adults report their earliest memories from somewhere between ages two and four, with the average settling around three and a half.
- The hippocampus, a structure critical for forming new episodic memories, continues maturing well past birth and into early childhood.
- High rates of neurogenesis in the infant brain are thought to disrupt the stability of newly formed memory traces.
- Children can form memories before age two, but these typically fade rather than persist into adulthood.

## Why Your First Years Vanish: The Infantile Amnesia Puzzle

Try it right now. Close your eyes and reach back for the earliest thing you can actually see in your mind. A kitchen? A face? Most people land somewhere around age three or four, and then the reel just stops. That blank stretch is called **infantile amnesia**: the ordinary, near-universal fact that adults cannot retrieve memories from their earliest years, typically before age 3 or 4.

In 1905, Sigmund Freud offered an explanation in his *Three Essays on the Theory of Sexuality*. He proposed that infantile amnesia helps protect us from childhood traumas and psychosexual conflicts, burying them out of reach. That view is no longer mainstream. Modern science looks somewhere else entirely, at how a first experience gets processed in the brain and at how memories are stored and retrieved.

The puzzle drew enough curiosity that when a piece on it ran on Eksiseyler on September 5, 2024, it pulled in more than 14,300 reads. The question is small and personal, and it turns out to sit right on top of some of the strangest machinery in the brain.

## The Building Blocks of Memory: Semantic vs. Episodic

Psychologist Endel Tulving drew the line between two kinds of remembering back in 1972, and the distinction still holds up. Semantic memory handles ideas that never happened to you personally. You know that "blue" names a color. You know a particular event happened on a particular date. None of that requires you to have lived through anything.

Episodic memory works the other way. It is built from things that happened *to you*: your first day of school, the afternoon a dog bounded up and sniffed your hand. The scene has a time and a place, and you were standing in it.

Here is the part that quietly reshapes a life. Episodic memories do not stay episodic forever. Over the years they shed their context and settle into general knowledge, a process sometimes called semanticization. So you stop recalling the specific dog that first terrified or delighted you, and you simply know what a dog is. Ask any adult to describe dogs and they will reach for the category, not the encounter. That is semantic memory doing the work.

Both types live in the same neighborhood, broadly speaking. Long-term declarative memories are distributed across various regions of the cortex, the brain's outer surface, rather than filed in one central drawer. That scattered storage matters for what comes next, because pulling a memory back out means coordinating regions that sit far apart.

One thing worth flagging early: the idea that infants run on both systems in equal measure is often repeated, but it is shaky. Babies clearly show semantic, preverbal memory. True episodic memory, the kind tied to a specific time and place, is generally thought to emerge later, somewhere around ages two to four.

## The Hippocampus and the Developing Brain: An Unsettled Connection

Your long-term memories live in the cortex, the wrinkled outer surface of the brain, spread across many different regions. But the structure that pulls them together, the hippocampus, is still under construction in a baby. Some accounts suggest the hippocampus cannot wire all those cortical regions, plus the left and right lobes, into one central information source until a child is 3 to 4 years old, because the nerve bundles linking the two hemispheres are still maturing. That timeline is an oversimplification, not a settled finding. Hippocampal and callosal development do continue after birth and are plausibly tangled up with infantile amnesia, but the tidy ages 3 to 4 claim is not firmly established.

Here is where the familiar telling trips over itself. It says that until those connections are in place, babies lean mostly on episodic memory. That is backwards. Infants are generally thought to rely on implicit and semantic-like memory, and true episodic memory, the kind tied to a specific time and place, emerges later, around 2 to 4 years. So the claim that babies are running on episodic memory is not supported.

What does hold up is the endpoint. Once development is complete, children and adults can recall long-term memories, and episodic memory begins to take on semantic characteristics. That shift is real. The first day of school, vivid and personal at the time, slowly sheds its context until all that is left is the plain fact that school happened.

## Neurogenesis: When New Neurons Make Us Forget

Neurogenesis, the production of new neurons, continues throughout a mammal's life. That fact alone unsettles the old idea that you are born with all the brain cells you will ever have. But the rate is not steady. In babies, neuron production runs far faster than it does in children and adults, and that speed turns out to matter enormously for memory.

Where does all this production happen? In the hippocampus, the structure that lets us reach stored memories and learn new things. Its usual job is to sharpen learning and memory. Under certain conditions, though, it does the reverse. When the infant brain churns out neurons at a furious pace, forgetfulness can actually increase, because the new cells crowd in on the older neurons that were keeping memory running.

Some scientists suspect that this flood of new neurons disrupts how the hippocampus forms and retrieves memories, and they have run experiments to test the idea against **infantile amnesia**. One of the sharpest used mice. First the animals were conditioned to link a place with a mild electric shock, building a memory, and a few more memories like it. Then the researchers toyed with the animals' neuron production to see what would survive.

Adult mice given drugs for several weeks to increase neuron production remembered fewer things. A second group, whose neuron production was slowed, remembered more. The result went further still: when the rate of new neuron production in baby mice was reduced to that of adults, those baby mice grew up and recalled memories that had been planted in them during infancy.

So if we cannot remember infancy because the hippocampus cannot pull memory storage regions in both hemispheres into one center, and because we rapidly produce neurons, is there an evolutionary upside? Possibly, as the story goes: infantile amnesia may be the price of a greater ability to learn new things. To build newer and more memories, we may have to sacrifice old ones. That does not mean episodic memory is thrown away. A 60-year-old can still recall a 30-year-old experience episodically. But as the interval widens, the efficiency of that recall drops.

## The Mouse Experiments: Proof That Neurogenesis Erases Infant Memories?

In 2014, a team led by Katherine Akers at the Hospital for Sick Children in Toronto published a set of mouse experiments in *Science* that turned a tidy hypothesis about infantile amnesia into something you could actually watch happen in a cage. The idea they were testing is simple to state and strange to sit with: the very process that builds a young brain may be the process that wipes its earliest memories.

Start with the background. Neurogenesis, the production of new neurons, continues throughout a mammal's life, and it happens largely in the hippocampus, the structure that lets us learn and reach stored memories. In babies, that production runs far faster than in children or adults. The general purpose of neurogenesis is to improve learning and memory, but under certain conditions it can do the opposite. Too many new neurons, as in an infant brain, can raise forgetfulness, because the newcomers crowd in on the older neurons that were holding a memory steady.

So some scientists hypothesized that this flood of new neurons disrupts the hippocampus's formation and access to memories, and they set out to test it. Here is how the experiment worked. Mice were conditioned to link a particular place with a mild electric shock, which gave them a memory, and a few more memories were layered on in the same way. Then the researchers toyed with the animals' neuron production to see what would survive.

| Group | What was done | What happened to the memories |
|---|---|---|
| Adult mice | Drugs for several weeks to increase neuron production | Remembered fewer things |
| Adult mice | Neuron production slowed | Remembered more |
| Baby mice | New-neuron production cut to the adult rate | Recalled infancy memories as adults |

The third row is the one that raises the hair on your arms. When the rate of new neuron production in baby mice was reduced to that of adult mice, those babies grew up and still remembered the memories given to them in infancy. Suppress the flood, and the early memory holds. Let it run, and the memory goes.

That is a striking result, and it fits the neurogenesis account of infantile amnesia neatly. It is also worth being precise about what it does and does not show. The experiments demonstrate that dialing neurogenesis up or down changes how much mice forget. They do not prove that the same dial explains why you cannot recall your own first birthday.

## Evolutionary Trade-Off: Why Forgetting Infancy Helps Us Learn

Here is the strange bargain at the heart of **infantile amnesia**: the same engine that lets a baby soak up the world at breathtaking speed may also be the thing wiping the slate clean behind it. The idea that forgetting our earliest years is an evolutionary advantage, that infantile amnesia is necessary for a greater ability to learn new things, is a plausible hypothesis discussed in the literature. It is not established as a proven evolutionary advantage. It is a compelling idea, though, and it fits neatly with everything we know about how the infant brain churns out new neurons.

Think about what neurogenesis is actually for. Its broad purpose is to sharpen learning and memory, so the brain keeps building fresh cells in the hippocampus, the structure that lets us reach stored memories and pick up new skills. But there is a cost buried in that benefit. When the production line runs too hot, as it does in babies, the flood of new neurons can crowd out and disrupt the older neurons that were holding existing memories together. Forgetting, in other words, may be the price of extraordinary absorbency. The story goes that to make newer and more memories, we have to give up some old ones, which is a simplification of a messier reality rather than a clean rule. Crucially, the trade is not a deletion of episodic memory. A 60-year-old can still pull up an experience from age 30 in vivid episodic detail. Widen the gap far enough, ask that same person about something from age 5, and the efficiency of episodic recall drops off.

So the forgetting is not a failure of storage. It is closer to a clearing of the ground, a way of keeping the learning machinery flexible enough to keep taking in the new.

Set that against the alternative. A brain that clutched every infant experience with equal grip would be spending its resources maintaining memories it can barely use, in a body and a world that have already changed. The adaptive reading, offered cautiously, is that infantile amnesia buys us something: a mind tuned for acquisition rather than archiving. Whether evolution "designed" it that way is an open question, and the honest answer is that no one has proved the advantage. What we can say is that the trade-off is real in the data, even if the evolutionary motive behind it stays a matter of interpretation.

## Handedness and Memory: The Ambidextrous Advantage (Reported, Not Proven)

Could using both hands shape how far back you remember? One account describes a study comparing 50 right-handed university students with 50 ambidextrous students, asking each to write down one early childhood episodic memory they personally recalled and one early childhood memory that had been told to them. Parents were then asked to verify these recollections. The specific study's design and sample size could not be reliably confirmed, so treat the details as unverified rather than settled.

According to that account, the ambidextrous participants reached further back. They reportedly recalled memories from earlier ages, and when they relayed memories that had been told to them, they did so in richer detail than the right-handed group. These specific findings could not be verified with confidence. If the pattern holds, it would suggest that the wiring between the two halves of the brain matters for how early and how vividly we can retrieve our own past, which is the heart of the infantile amnesia puzzle.

The proposed explanation centers on the **corpus callosum**, the thick bundle of nerve fibers that bridges the left and right hemispheres. Some research links atypical handedness to differences in the corpus callosum, but the leap to a memory advantage is speculative and not firmly established.

Here is where a popular version of the theory goes wrong. Contrary to the common telling, episodic memories are not simply encoded on the left and pulled from the right, with childhood amnesia vanishing the moment that loop closes. The HERA model does propose a left-encoding, right-retrieval asymmetry, but the claim that this pattern causes childhood amnesia to disappear is not an established mechanism. What is well supported is narrower: semantic memories, the general facts we hold without any personal scene attached, are typically encoded and recalled in the left hemisphere, at least in most right-handed people.

The broader claim, that a stronger connection between hemispheres makes episodic memory more powerful because it draws on both the right and the left, is not firmly established. Episodic memory does engage widespread bilateral networks, and the maturing corpus callosum may support integration. Still, that is a hypothesis under investigation, not a finished answer to why our earliest years slip away.


## Frequently asked questions

**What is infantile amnesia?**

Infantile amnesia is the ordinary inability of adults to recall memories from their earliest years, usually anything before age 3 or 4. Almost no adult can summon a genuine first-person memory of being a baby, even though those years were packed with new sights, sounds and faces.

**Why can't I remember being a baby?**

Two forces are usually blamed. The hippocampus, the brain's memory hub, is still wiring itself up in infancy, and the nerve bundles linking the brain's two hemispheres are not finished either. On top of that, babies produce new neurons at a furious rate, and that flood of fresh cells disrupts the memories already stored.

**How does the hippocampus affect infant memories?**

The hippocampus is essential for forming and retrieving memories, yet in babies it may not pull information from both hemispheres into one central source until roughly ages 3 to 4, because the connecting nerve bundles are still developing. Rapid neurogenesis inside it adds a second layer of interference.

**Was Freud's theory of infantile amnesia correct?**

Sigmund Freud, writing in 1905, argued that infantile amnesia shields us from childhood traumas and psychosexual conflicts. His view is no longer mainstream. Modern psychology favors neurobiological explanations, pointing to the developing hippocampus and high rates of neuron production rather than repression.

**What role does neurogenesis play in forgetting infancy?**

Neurogenesis, the production of new neurons, continues throughout a mammal's life, and it happens far faster in babies than in children or adults. Those new neurons crowd and disrupt the older circuits that keep existing memories running, so the earliest memories fade as fresh cells take over.

**Did experiments with mice prove why we forget baby memories?**

Experiments with mice support the neurogenesis hypothesis. Researchers first conditioned the animals to link a place with a mild electric shock, then altered their neuron production. Adult mice given drugs for several weeks to increase neuron production remembered fewer things, while mice whose neuron production was slowed remembered more.

**How does the corpus callosum influence childhood memories?**

As the story goes, a thicker corpus callosum, the nerve bundle joining the left and right hemispheres, may allow stronger communication between the two sides and therefore better memory recall. That link is speculative. Semantic memories are encoded and retrieved in the left hemisphere, while the idea that episodic memories are encoded on the left and retrieved from the right is not an established mechanism.

**Is forgetting infancy an evolutionary advantage?**

Some scientists hypothesize that infantile amnesia is necessary for a greater ability to learn new things, since one purpose of neurogenesis is to support learning and memory development. It is not proven. The idea is that forming newer and more memories requires sacrificing old ones, though episodic memory is not simply discarded. Editorial note: Details that remain unsettled in the research literature, including the precise mechanisms behind early memory loss, are presented here as open questions rather than settled facts.

Canonical: https://curio.madeda.com/infantile-amnesia-why-you-can-t-remember-being-a-baby/