Image by The U.S. National Archives via Flickr
Many thanks for your comments on my last post. Brain development has certainly been proposed as an explanation of childhood amnesia, and it undoubtedly plays a big role. For example, we know that prefrontal regions are important in the construction of autobiographical memories, and these regions are known not to be fully mature until around age 5.
And yet the Tustin and Hayne1 data show that brain development can't be the whole story. We need to distinguish among the three main component processes of remembering: encoding, storage, and retrieval. If the brain were not mature enough to encode and/or store memories properly in the first few years, we would be amnesic about them at whatever age we were tested, whether in childhood or in adulthood. In contrast, the Tustin and Hayne findings show that we remember (some of) these events and then forget them. We undoubtedly become better at retrieving memories as our prefrontal areas mature, but it's not all down to maturation. As Tustin and Hayne argue, 'young children begin to encode episodic memories very early in development and at least some of these memories remain accessible until early adolescence. Over time, however, access to these memories is gradually lost because the information is too lean or too poorly organized to be retrieved over very long delays' (p. 1058). We forget, in other words, because the information that we are trying to recall is not of a sufficiently high quality.
One way in which we organize our memories is by talking about them. Toddlers get involved in conversations about past events from an early age, and I myself noted down several such examples when Athena was between 18 and 24 months. In one phone conversation with her mother, Lizzie, she talked accurately about a visit from her godfather a few weeks earlier, and how she had said goodbye to him as he left on a train. Pointing to a papercut picture she had made with Lizzie three months earlier, she said ‘Mummy cut.' At nearly two, she came across a postcard from Japan, sent by her grandparents five months earlier. She had no problem remembering who it was from and where it had been sent from.
These conversations about the past are initially quite heavily structured (or 'scaffolded') by caregivers, but children become more equal partners in them through the preschool years. Here's a passage from my book describing a bedtime game we used to play with Athena:
It was around this time that we started our bedtime routine of ‘What We Did Today'. Lizzie and I would lie down on the bed on either side of her and together we would go through the day's events. Beyond its value as a moment of shared intimacy, this was a way of putting some good research into practice. The psychologists Katherine Nelson and Robyn Fivush2 have shown that children get involved in conversations about past events from soon after their second birthdays, and gradually take on ever-greater responsibility for joint storytelling about the past. Furthermore, parents' willingness or skill in supporting these dialogues has been shown to have a big effect on children's developing storytelling abilities. Longitudinal studies, following the same samples of families over periods of time, show that parents who have an ‘elaborative' style in their interactions have children who produce more sophisticated memory narratives. Adopting an elaborative style means producing orienting information (details on where the event occurred, and who the actors in the drama were) and evaluative information (all the emotional details of how things looked, seemed and felt that gave the event personal significance). More than simply reiterating the crucial information, our efforts were about allowing Athena to step back into the event and re-experience it. This was her drama, and we were helping her to take centre stage.
A Thousand Days of Wonder: A Scientist's Chronicle of His Daughter's Developing Mind
Readers of this blog will know that I am not a big one for parenting advice. But when I was asked by the Psychology Today team a while ago to suggest how a bit of psychological research could be turned into practical advice, I thought of this game we used to play with the kids. Talking about the past makes for a warm family moment, but it also seems likely to help children to organize their memories, especially when adults put a bit of effort into creating a rich memory conversation.
And in some research published since I wrote that passage, Fiona Jack and colleagues3 have shown that these effects of elaborative style persist into adolescence. They took measures of elaborative style in 17 mother-child pairs when the children were aged between 2 and 4. Maternal elaborations were defined as 'introducing an event, moving to a new aspect of the event, or adding more information about a particular aspect of the event under discussion' (p. 498). For example, open-ended questions such as wh- questions ('What did you have to do with the helicopter?') were counted as elaborations. In their analysis, the researchers distinguished this kind of utterance from repetitions, which simply repeated the content of previous utterances without adding any new information.
Jack and colleagues then followed the kids up in early adolescence, and asked them about their earliest memories. One measure of elaborative style, the ratio of elaborations to repetitions, turned out to be of particular significance. Kids whose mothers had a higher ratio of elaborations to repetitions reported earlier memories. The authors took this evidence as 'consistent with the hypothesis that past-event conversations during early childhood have long-lasting effects on autobiographical memory' (p. 496). You can read the abstract of the article here.
This study is impressive in many ways, not least because it covers such a long longitudinal time span (the researchers had to hang around for about a decade before they could get their follow-up data). The authors were also able to exclude the children's own language skills as a possible explanation, showing that it wasn't just the fact that some kids had better language that caused the association. Rather, it was specifically the way in which mothers talked about the past that was important. To show the effect, the authors argue, mothers needed to produce a relatively high proportion of elaborations against a background of a relatively low proportion of repetitions. Such a pattern of utterances constitutes a particularly coherent narrative style, which is in turn a powerful organizing force for early memories.
1 Tustin, K., & Hayne, H. (2010). Defining the boundary: Age-related changes in childhood amnesia. Developmental Psychology, 46, 1049-1061.
2 Nelson, K., & Fivush, R. (2000). Socialization of memory. In Oxford handbook of memory (edited by E. Tulving and F. I. M. Craik). New York: Oxford University Press.
3 Jack, F., MacDonald, S., Reese, E., & Hayne, H. (2009). Maternal reminiscing style during early childhood predicts the age of adolescents' earliest memories. Child Development, 80, 496-505.