Psychologists at Emory University in Georgia, USA, say that only children under the age of seven have any chance of remembering.
The psychologists explored the memories of 83 children over a period of six years. Children were quizzed at age three about experiences like going to the zoo, and then divided into groups. Each child participated once more in the experiment, tested to see whether he or she could recall the event at the age of five, six, seven, eight or nine.
Coined by Sigmund Freud, the term ‘childhood amnesia’ is not a new phenomenon, but the time it starts to occur has, until now, remained a little hazy.
"Our study is the first empirical demonstration of the onset of childhood amnesia," says Prof Patricia Bauer, who led the study. "We actually recorded the memories of children, and then we followed them into the future to track when they forgot these memories."
The psychologists found that the children’s earliest memories began to fade at around seven years old. Children between the ages of five and seven remembered 63 to 72 per cent of the events, while eight- and nine-year-olds recalled only about 35 per cent.
But athough the younger children remembered more events, they weren’t so good at remembering the details. So while they might remember what animals they saw at the zoo, they might not be able to recall what flavour ice cream they ate.
The older children, on the other hand, were better at remembering the details of those events that had stayed with them – possibly because they had better language skills and so were able to elaborate the memory and cement it in their minds.
Now that the psychologists have found the age at which childhood amnesia sets in, they hope to pinpoint the age at which we acquire our adult memory system.
"Between the ages of 9 and 18 is largely a no-man's land of our knowledge of how memory forms," says Bauer.
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