|Remembering early childhood memories|
Most of us have no memories from the first three to four years of our lives. In fact, we tend to remember very little from life before the age of seven.
And when we try to think about our first memories, it is often not clear whether they are real or just memories based on images and stories others tell us.
The phenomenon, known as "childhood amnesia", has baffled psychologists for more than a century, and we still don't fully understand it.
Perhaps the reason we don't remember our childhood is that infants and children do not have a fully developed memory. However, babies as young as 6 months old can form short-term memories lasting minutes and long-term memories lasting weeks, if not months.
Of course, memory abilities at these ages are not the same as those of adults, as they continue to mature into adolescence.
In fact, evolutionary changes in basic memory processes have been put forward as an explanation for childhood amnesia, one of the best theories we have so far.
These basic processes involve several areas of the brain, and include the formation and preservation of memory, and later retrieval.
A child's ability to tell a story as it happens can help predict how well he or she will remember it months or years later.
One laboratory group conducted this work by interviewing young children brought to accident and emergency departments for common pediatric injuries.
Young children over 26 months of age who could narrate the event had remembered it for up to 5 years. Whereas children younger than this age who were unable to narrate the event may remember little or nothing at all.
Most research on the role of language focuses on a particular form of expression called narrative, and its social function. When parents with very young children remember past events, they implicitly teach them narration skills, i.e. what kinds of events are important to remember and how to organize talking about them in a way that others can understand.
In contrast to recounting information for factual purposes, recollection is about the social function of sharing experiences with others.
In this way, family stories preserve the accessibility of memory over time, and also increase the coherence of the narrative, including the chronology, subject matter and degree of emotion.
And more coherent stories are remembered better.
Memories carry different social functions in different cultures. For example, adults in cultures that value autonomy (North America and Western Europe) tend to report early childhood memories more than adults in cultures that value connectedness (Asia and Africa).
In cultures that promote more independent self-concepts, parental memories focus more on children's individual experiences, preferences, and feelings, and less on their relationships with others, social routines, and behavioral norms.
For example, an American child might remember getting a gold star in preschool while a Chinese child might remember his class learning a particular song in preschool.
While there are still things we don't understand about childhood amnesia, researchers are making progress.
For example, there are more prospective studies that follow individuals from childhood into the future. This helps provide accurate accounts of events, and is better than asking teens or adults to remember past events that were not documented.
As neuroscience advances, there will undoubtedly be more studies linking brain development to memory development. This should help us develop other measures of memory besides verbal reports.
In the meantime, you should know that although we can't remember certain events from childhood, their accumulation leaves lasting effects that affect our behaviour.
The first few years of our lives may be forgotten, but they remain powerful in shaping the adult personalities we become.
Jane Shinsky is Senior Lecturer and Director of the Baby Lab in the Department of Psychology at Royal Holloway, University of London. Shinseki does not work for, consult, own or receive funding from any company or organization, and she has not disclosed any relevant affiliations after her academic appointment.