While most adults cannot remember anything from their very early years, a New Zealand study suggests that exposing very young children to vivid and unusual situations will aid recall in later life.
The work, by three researchers from Otago University's psychology department, sought to test the idea of childhood amnesia, which says adults cannot remember events from before they were 3 or 4.
Two researchers visited 50 Dunedin children in 1999 and asked them to play with an unusual toy. They visited the same group again in 2005 to see if they could remember the first visit.
About a fifth could, including two children who were under 3 years old, said the study's lead author, Fiona Jack.
The findings buck the trend of most previous Western studies, which place the earliest recollections at about 3 years of age.
Dr Jack said other studies had tested recall of significant events, such as medical operations, which could have been influenced by family stories or photos.
"We found that over the long term, not many of the children did remember it, but of those who did, some were as young as 2. The youngest was 27 months at the time it occurred.
"Basically, I think the main contribution of our study is that it's the first objective evidence that children as young as 2 can encode memories of the experiences they have, and retain them over long periods of development."
Dr Jack said the study was the first of its kind to use a lab-based event to test memory recall, and the subjects would have had little or no reminders of the toy during the six-year interval.
The memory of 80-year-old Betty Ruffell backs up the theory - she claims to vividly recall experiences from her very early childhood.
Ms Ruffell welcomes the findings because she can vividly remember the fancy cot and wooden highchair she used when a toddler.
"I can remember sitting in a highchair, and I can remember exactly what the highchair was like. I can remember eating porridge in it. I can remember lying in my cot, and it had a net over the top so I could climb out, and it had pictures on the panel.
"I can also remember playing in a great big pram going to the village green to see the hunt meet. I would have been around about 2 then as well."
Although she can clearly recall many events until her 18th birthday, memories of the rest of her life have been reduced to a few select events.
"Of course as you get older and older, you can't remember yesterday."
Dr Jack said the results, published in the United States journal Child Development, could have implications for clinical or legal settings.
"What our research shows is basically that if an individual claims to remember an event at [age 2], it's possible that is a genuine and accurate memory they are recalling."
TOP TIPS FOR REMEMBERING
Researcher Dr Fiona Jack says the mind is like a muscle which must be used to keep it strong. And the more you use it, the longer you will retain memories. She suggests:
* Talking about an event soon after it happens.
* Having parent-child conversations to strengthen early memories.
* Reminiscing about the event on a regular basis.
* Using cues such as smells or photos to spark memories.