The current consensus among memory researchers is that we need other capacities to be in place, skills that are not directly to do with the storage of information, before we can hope to carry our memories forward into later childhood and adulthood. One such factor is language. As soon as you can use words to describe your experience, you begin to have an entirely new way of encoding, organizing and retrieving information about the past. In one recent study conducted at the University of Leeds, the psychologists Catriona Morrison and Martin Conway asked adults to generate childhood memories in response to cue words naming everyday objects, locations, activities and emotions. By looking at existing data on the average age in infancy when these words are acquired, they were able to show that the earliest memories always lagged behind (by several months) the age at which the corresponding word was learned. “You have to have a word in your vocabulary, ” Morrison observed, “before you’re able to set down memories for that concept.” As has been noted many times, it is unlikely to be a coincidence that the end of childhood amnesia corresponds to the period in which small children become thoroughly verbal beings.
Fernyhough, Charles. Pieces of Light. HarperCollins, 2012. p. 64–5