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Q: When does our brain start to register our first memories?

A: Adults usually cannot remember things that happened before they were three to four years old. This has led to the idea that children younger than this cannot remember things. However, we now know that even very young infants have memories.

There are two types of long-term memory. What we usually think of as memory is called declarative memory. This refers to memories that can be consciously recalled, such as remembering the name of your neighbour or recalling what you ate for dinner last night.

But there is a second type of long-term memory, non-declarative memory. This refers to information that is retrieved unconsciously, for example, how to ride a bicycle.

It is clear that infants have non-declarative memory. For example, most mothers know that newborn babies quickly develop a preference for their voice over the voices of other people. But declarative memory was thought to develop only in older children. The problem is that testing memory typically relies on asking kids whether they remember something.

The duration of memory increases dramatically with age. One study, for example, indicated that two-month-old infants could remember a certain task only for a day or two, while one-year-old babies could remember a similar task for two months.

Recent research that uses non-verbal tests indicates that even declarative memory can be observed in infants as young as two months old.

Remarkably, the duration of memory increases dramatically with age. One study, for example, indicated that two-month-old infants could remember a certain task only for a day or two, while one-year-old babies could remember a similar task for two months.

Thus, even very young infants have memory, though their ability to remember things gets much better over the first two years of their lives. Parents should take advantage of this knowledge by exposing their infants to enriching experiences that will contribute to development of childhood memories.


•Professor George Augustine, professor of neuroscience and mental health, Lee Kong Chian School of Medicine, Nanyang Technological University


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A version of this article appeared in the print edition of The Straits Times on July 17, 2015, with the headline 'Q & A'. Print Edition | Subscribe