It is a question that has  long puzzled scientists and  psychologists: Why do we forget our early childhood, the most carefree – and arguably happiest – time of our lives?

Now a pair of scientists believe they have worked out why the phenomenon, christened infantile amnesia by Sigmund Freud, exists – and why we’ll never get those memories back. 

They said that the rapid growth of cells in the brain’s memory hub in the first years of life means that key connections between existing cells are broken.

As a result, memories stored there become impossible to retrieve.

The Canadian Neuroscience Meeting heard this could explain why young children can remember an event such as a birthday party only for a few weeks or months before it disappears.

In contrast, the connections in the brain of older children and adults are more stable, allowing memories to be properly stored.

The theory comes from husband and wife team Paul Frankland and Sheena Josselyn, of the University of Toronto, who showed that boosting cell production in the memory hub of adult mice made it easier for them to forget. 

They also found puppies which are unable to make memory cells as normal had better memories. 

Previous studies have shown that we can’t typically recall events that occurred before the age of two or three and only have patchy memories of things that took place between three and the age of seven.

Explanations for phenomenon have ranged from memories fading over time, to memory formation being tied to the development of speech.

However, the researchers believe their theory to be the most plausible. They said: ‘Why infantile amnesia exists has long been a mystery. 

We think our new studies begin to explain why we have no memories from our earliest years.’ 

They added that there are some advantages to not remembering every detail of childhood.

For instance, their two-year-old daughter recently burst into tears when the lights were dimmed for her candle-topped birthday cake.

They said: ‘This event seems permanently etched in our memories and we can vividly recall many details of the not-so-happy birthday.

‘Our daughter remembered parts of this event too, at least for a day or two.  The next day, she exclaimed “no candles” while shaking her head vigorously.

‘Have we scarred our daughter for life? Perhaps. But if she is like the rest of us, she will not explicitly remember the “birthday candle incident” when she is an adult.’

 

By Fiona Macrae

Source: Daily Mail – http://goo.gl/UdzeD