Our childhood memories could go back further than we thought

OUR earliest childhood memories could begin from the age of two, new research has revealed.

Scientists have discovered that the hippocampus, the area of the brain responsible for remembering past events, can be triggered before toddlers even learn to speak.

The breakthrough may lead to earlier diagnosis of developmental brain disorders such as dyslexia and autism.

Previous research had suggested the average age of our earliest memories was three-and-a-half.

In the first study of its kind, 22 twoyear-olds had their brains scanned using MRI while sleeping.

The scans showed more activation in the hippocampus when a lullaby they had previously heard was played, regardless of whether it was played as recorded – or played backwards.

The children first listened to a lullaby while playing with a stuffed dog so that memories of the song would be associated with the cuddly toy.

The children went to sleep inside the MRI scanner and while they slept the researchers played recordings of either lullabies they had heard earlier or unfamiliar ones.

The toddlers were also tested, while awake, on whether they could remember in which room they had heard the

‘Our results provide evidence of a connection between hippocampal function and early memory ability’

song or if they could link it with a toy.

The highest response was observed in those who correctly remembered the place where they learned the song – and a toy associated with it.

Prof Simona Ghetti, of California University in Davis, said: “One of the most fascinating questions in psychology and neuroscience pertains to how young children gain the capacity to remember their past.

“Early hippocampal processes have been implicated in this ability – but a lack of viable methods has hindered assessments of their contribution in early human development.

“Our results provide direct evidence of a connection between hippocampal function and early memory ability.

“This experimental approach overcomes previous challenges and promises to pave the way to investigations linking changes in brain function to early development of learning mechanisms – including applications to typical and atypical development.”

Previous research has proved difficult in very young children because it requires them to complete a task while lying still with their head inside a large, noisy machine.

The new research was published in Proceedings of the National Academy of Sciences.