What is your earliest memory?

As hard as you try, the chances are that even your earliest memories were from around the age of three or four years old. Even these early memories will likely be quite sporadic, focused on a moment when you felt something quite strongly.

In fact, the majority of your childhood memories will likely be from the age of seven onwards.

And, according to researchers from Yale, there’s good reasons for this. In a paper recently published in the journal Science, the team explain why exactly it is that – despite the extreme learning curve we go on in our early years – very few of our infant and early childhood experiences are committed to long-term memory.

For a long time, scientists and child experts have believed that the reason that we can’t remember our infancy is as a result of the early developmental stage of the hippocampus.

This weird, seahorse-shaped part of your brain is responsible for learning and memory, and it continues developing until your late teens. Thus, researchers believed that the hippocampus just doesn’t have the capacity to create long-term memories of our early childhood experiences.

However, in their study, the researchers showed images to small children and then showed them the same images down the line to see if they remembered them.

They tested 26 infants from four months to two years old – with half of the sample group being over one year old – using a unique method to test the children’s memories, as Yale Professor Nick Turk-Browne explained in a statement:

“When babies have seen something just once before, we expect them to look at it more when they see it again. So in this task, if an infant stares at the previously seen image more than the new one next to it, that can be interpreted as the baby recognizing it as familiar.”

And their findings were surprising, disproving earlier theories that memories are not created in infancy. Without question, all the infants remembered the images – with children over the age of twelve months remembering the images more strongly, suggested by their extended interaction with the familiar image.

The team’s findings suggest that, counter to what was previously believed, infants do commit their experiences to their long-term memories.

These types of long-term memories, known as episodic memories, were clearly present amongst all of the children in the test group (though they were stronger as the child got older), leading researchers to question what exactly happens to these memories over time.

With both our own anecdotal experiences and test results proving the phenomenon of ‘infantile amnesia’ (the name for our lack of ability to recall our infancy), researchers are still mostly at a loss as to why exactly the hippocampus doesn’t store these early experiences.

However, Professor Turk-Browne is of the opinion that the memories are still stored somewhere in the hippocampus, we have merely lost our ability to access them as adults.

Thus, the team’s work into infant hippocampal memories endures, with the researchers now at work on an innovative project involving home videos taken from the perspective of infants, as he continued:

“We’re working to track the durability of hippocampal memories across childhood and even beginning to entertain the radical, almost sci-fi possibility that they may endure in some form into adulthood, despite being inaccessible.”

So perhaps in the future there will be a way of unlocking those as-yet inaccessible childhood memories – or at least fully understanding why we can’t.

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