What's the first thing you can remember?
Rozencrantz attempts to answer this question but fails. He opens his mouth, hesitates, then admits, “No, it’s no good. It was a long time ago.”
Growing agitated, Guildenstern presses him, “No, you don't take my meaning. What’s the first thing you remember after all the things you’ve forgotten?”
A spark of realisation appears in Rosencrantz's eyes “Oh! I see!” He hesitates again, and it’s gone. “I've forgotten the question.”
This vignette is taken from Tom Stoppard's Rosencrantz and Guildenstern Are Dead. The play highlights our fascination with our earliest memories, and begs the question: just how far back can our memories go?
This question has intrigued scientists since the first formal study in 1898. A large body of work has shown that adults cannot remember much before the age of three or four. The age of our first memory is subject to a vast variety of variables. Perhaps the most surprising of these is the culture a person is brought up in. One study from 2000 showed that the Maori people of New Zealand are able to recall memories earlier than people from other cultures such as Korean people, whose earliest memories appear more than six months later.
Regardless of the age of our first memory, we all suffer from an absence of memories from our earliest days. This phenomenon is known as childhood amnesia. The majority of studies on childhood amnesia have used adult subjects. However, with fresh approaches come fresh insights, and a new study, published in the journal Child Development, concentrates on child subjects in order to bring new evidence to the memory mystery.
This latest paper comprises two studies led by Dr Carole Peterson, conducted over two years. In both studies, children aged between four and thirteen years were asked for their earliest three memories. The children were brought back two years later to answer the same question again: “What's the first thing you can remember?”
The use of children in this study aims to address the problem of why adults cannot remember anything before about the age of three or four, while children as young as two are able to talk about their past memories. The first round of questions established that the youngest children had memories from when they were just 18 months old. These were confirmed by their parents. The two-year gap between the studies created a shift to memories that occurred several months after those initially reported. Furthermore, the younger children were unlikely to provide the same memories that they had in the initial questioning, whilst older children repeated the same memories.
When prompted with facts about the memory they had given two years earlier, the younger children who gave different memories showed no recollection of the initial memory. Some even denied that the events had happened to them at all. However, when the older participants were prompted, they were able to remember the memories that they had shared initially, even if they did not match their later responses. These results present empirical evidence for the hypothesis that the disappearance of memories begins in our early years and that children also suffer from childhood amnesia. The evidence also shows that the older we get, the more consistent we are in recollecting our earliest memories.
Why does childhood amnesia occur at all? One theory proposes that it could be due to the difference between episodic memory, which encodes events, present in children and adults. Development of the hippocampus at around the age of four means that after this age the brain is better at forming memories by tying together pieces of information. The delayed development of this part of the brain occurs because in the early years the brain’s energy is better spent in the acquisition of semantic memory, such as language.
Language may also play an important part in understanding childhood amnesia. The assumption that it is the ability to linguistically encode memories, which makes them accessible to language proficient adults, directly ties memory recollection to linguistic development.
Evidence from studies done with adult subjects backs up this theory as it is not until the age of three or four that children are able to produce grammatically correct sentences. However, the results of Peterson’s study show that since these early memories are lost with age and the language barrier does not stop younger children accessing earlier memories, this theory may not carry as much weight as originally thought.
All things considered, whatever the reasons are for the observations made in this study, those of us getting older will be happy to hear that it's not just our later years which make us forgetful, but our earlier ones too.