Many of us can vividly recall childhood memories; however, most will not remember the moments just after birth and the first two years of life as we acclimated to the outside world.
As we grow up, we find it difficult to remember those early moments of our lives, from birth to around 2-3 years old. This phenomenon is what scientists refer to as “childhood amnesia.”
You will never remember the moments from your first birthday. (Illustrative image: iStock).
While you might recall and describe the details of your second birthday party for months after it happened, just one year later, those memories will fade and eventually disappear entirely.
So why do we tend to forget these very early memories? The answer is not that we are unable to retain information as children, but rather because at that age, our brains are not yet functioning in a way that integrates information into complex neural patterns known as memories.
Young children can remember transient events, such as who their parents are or knowing to say thank you when given candy. This is referred to as “semantic memory.”
However, before the ages of 2-4, children do not possess “episodic memory”—the memory of specific details of a particular event. Such memories are stored in the cortex.
For instance, auditory memories are processed in the auditory cortex located on either side of the brain, while visual memories are processed by the visual cortex at the back of the brain. A brain region known as the hippocampus connects these different types of memories into a centralized source of information.
Patricia Bauer, a Psychology Professor at Emory University, explains: “The hippocampus, neatly located in the center of your brain, is responsible for linking all types of semantic memory and episodic memory together, thereby forming long-lasting memories.”
It is not until the ages of 2-4 that the hippocampus in the brain starts to link memory fragments together to form long-term memories. (Image: iStock).
Nora Newcombe, a Psychology Professor at Temple University in Philadelphia, states that we do not remember our early memories because it is only between the ages of 2-4 that the hippocampus begins to connect memory fragments together.
According to Professor Newcombe, before the age of 2, children are just starting to familiarize themselves with how the world operates and gather semantic knowledge, making the complexity of episodic memory unnecessary and potentially distracting.
However, another hypothesis suggests that we may actually retain these early memories as children, but struggle to recall them as adults.
A study published in 2023 in the journal Science Advances found that childhood memories “forgotten” can be restored in adult mice by stimulating neural pathways with light.
Scientists created mice with autism spectrum disorder (ASD) by stimulating the immune system of female mice during pregnancy, as previous research suggested that autism is linked to the mother’s immune system overreacting during pregnancy.
This immune activation helped prevent early memory loss in the offspring by affecting the size and plasticity of specialized memory cells in their brains.
When these cells were optogenetically stimulated in adult mice without autism, the forgotten memories could be retrieved.
Co-author of the study, Associate Professor Tomás Ryan, stated: “Although this research was conducted on mice and has not yet been studied in humans, it is significant in advancing our understanding of memory and forgetting in child development, as well as overall cognitive flexibility in autism research.”
