If you’re like most people, you probably don’t start to have clear memories of childhood until you were somewhere between 3 and 5 years old. By now, though, when your baby is nearly a year old, she probably has favorite foods, favorite toys, and favorite songs, all of which have a hard time becoming favorites before she can remember them from day to day.
There’s a difference between short-term and long-term memory in the same way that there’s a difference between learning a new skill that you’ll know how to do later, and forming a narrative memory of learning that skill that you can describe later. Studies of the first kind of memory are easier to set up because infants don’t have the verbal skills to describe those narrative memories if they have them, because they don’t need to be tested for as long, and because not remembering one episode that’s part of a study is not the same as not remembering anything at all from childhood. If babies only have very selective long-term memories, there’s no way of ensuring that the memory that’s being tested will be one of the ones that stays.
Still, some long-term testing of young children’s long-term memories, or lack of them, which Freud called ‘infantile amnesia,’ has been the subject of some studies. A 2013 study at Emory University in Atlanta, for instance, looked at the fact that there seem to be several developmental drop-off points in children’s memories. At these points - around 3 and around 7 - many children seem to start to remember significantly less about things they’d remembered for years.
There are a few different theories about why this is. One of the first is the trouble of not really having any context for really early childhood memories. According to this theory, they’re there, but because children will never again see the world the way they did in the year or two of life, nothing is ever going to remind them of these memories. Or, relatedly, the idea that before children learn language, they have no way of developing their thoughts into narrative memories they can retrieve. This idea is supported by the fact that children from cultures that emphasize narrative thought processes, and children whose parents talk to them more about their lives, tend to have earlier first memories.
A second, related theory is that in the first few years of life, the brain is still developing, particularly the connection with the prefrontal cortex. The prefrontal cortex is where memories are stored, and while very young children might make as many memories as anyone else, they don’t usually have the neural structure to recall them until they’re a little older.
Whether either of these are true or not, though, it’s still true that many children do have first memories that trace back to before these drop-off points. Since pretty much all credible thinkers have moved past Freud’s idea that children are blocking out the inappropriately sexual thoughts they had in infancy, there’s also no reason to think earlier first memories aren’t a good thing. And it’s true that you, as your baby’s parent, do have an influence on when her long-term memory kicks in. Children whose parents start to talk (and listen!) to them about their recent memories at an early age are more likely to have earlier first memories. It’s also not all in your hands, as first memories also tend to be associated with strong positive or negative feelings, or with major events in young children’s lives.