In last February's issue of Child Development, I found a paper from a team that investigates the problem of childhood memories among the Maoris. It turns out that when you ask them, Maoris produce the earliest childhood memories on record: 2.5 years on average (the average American has 3.5, Asian memories being even older on average). Their Pakeha neighbours also have first memories 3.5 years old, with Maori first memories at least 10 months earlier.
Pictures: a Maori man (right), and writer Georges Perec (left), whose book W ou le souvenir d'enfance (W : a childhood memory) is a twisted autobiography dwelling on his absolute lack of childhood autobiographical memories.
One possible explanation might be that Maori children hear more stories concerning their early childhood than do other children, as we know that these narrations can help stabilize, or even recreate, first memories. Reese, Hayne and MacDonald investigated that option by recording Maori and Pakeha mothers while they were discussing episodes of their children's lives ith their children. They try to push for this explanation in their paper, but as they acknowledge, the data fall short of confirming their view.
Compared to Pakeha mothers, Maori mothers' narrations of their children's early past are not more specific, detailed or abundant. Weirdly enough, though, their account of childbirth are much more vivid than Pakeha mothers' – and this correlated nicely with the age of the earliest autobiographical memories in children. The problem, of course, is that being born is hardly a typical episode in autobiographical memory (unless one is Tristram Shandy). I very much doubt that the results could be due to the fact that Maori informants would present their mother's account of their birth as a personal memory, thus creating the one year on average difference with Pakehas and Americans. The authors would tell us if such an obvious explanation was available.
So the jury is still out on what makes Maoris remember earlier episodes of their life. I have no theory and will just make a remark: as often happens, cultural and social influence in childhood is reduced to parental influence (in this case, the mother). But there is much more to achild's social environment than her parents. Slightly older peers may be somewhat better placed to observe, record, and endlessly repeat trivial episodes of the early life of a child (being lost in a mall, peeing oneself, etc.). I speculate that children's peer culture might be a possible key to the problem.