For many, recalling a specific event is not a challenging task. However, memory loss appears inevitable at two stages of life: in old age and during childhood.

While memory loss in old age is understandable due to declining physiological functions, the idea of children experiencing "amnesia" is harder to grasp.

Childhood is widely regarded as the most precious learning phase, where individuals acquire complex skills such as language and walking. Research even suggests that cognitive training begins in the place. Despite this, most people cannot recall their first words or early friendships. So, where do our childhood memories go?

Why Do We Have No Memory of Early Childhood | Childhood Amnesia

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Memory, Language, and Self-Awareness

A longstanding theory posited that children under seven were incapable of forming stable memories, making forgetfulness inevitable. However, a series of experiments in the 1980s revealed that children start forming memories as early as age three. Six-month-old infants can retain memories for at least a day, while two-year-olds may recall events from a year prior. By four-and-a-half, children can remember 80% of events from when they were three, but by age seven-and-a-half, this figure drops to 40%.

These findings suggest that children are capable of creating and retrieving memories. The puzzling part is why these memories fade rapidly after age seven. Researchers have since focused on understanding the causes of memory loss rather than questioning whether children can form memories. Factors like language development and self-awareness play a significant role.

Language appears to influence childhood memory. In one experiment, researchers interviewed children who had visited the emergency room for minor injuries. Those who could verbally describe the incident at the time were more likely to recall it five years later, compared to children who couldn't articulate their experiences. This suggests that experiences not translated into language may be lost. From ages one to six, as language skills improve significantly, children's memory capacity strengthens in tandem.

Another crucial factor is self-awareness, which typically develops between 18 and 24 months when children begin using terms like "you" indicating an emerging sense of self. Studies show that individuals from cultures emphasizing personal experiences and emotions, such as North America and Europe, have earlier and more detailed childhood memories compared to those from cultures prioritizing social norms and collective behavior, such as in Asia and Africa.

While language and self-awareness enhance memory, other factors contribute to the loss of childhood memories.

Experiments on Neural Activity

Researchers noticed that not all childhood memories are lost. For example, skills like walking, swimming, and cycling are retained, whereas episodic memories of events are more prone to fading. The hippocampus, a region in the brain’s temporal lobe, plays a critical role in long-term memory. It filters and temporarily stores information before transmitting important sensory details to long-term memory regions.

Infants form approximately 700 new neural connections per second, prompting researchers to investigate whether these neurons contribute to memory loss. A study conducted by the University of Toronto explored the link between neurogenesis and memory retention. In one experiment, mice were conditioned to associate a mild electric shock with a specific environment. Some mice were later placed in a running wheel to boost neurogenesis. When returned to the shock environment, these mice largely forgot their fear, while those without neurogenesis stimulation retained the memory.

In another experiment, young mice were fed a drug to slow neural growth. Researchers hypothesized that these mice would show better memory retention compared to untreated mice. The results supported this hypothesis, indicating that faster neural growth might interfere with memory retention.

The Culprit: New Neurons

These studies identified the culprit behind childhood memory loss: new neurons. Researchers speculate that during growth, mammals generate neurons in the hippocampus at a rapid rate, particularly in the dentate gyrus. These new neurons compete with existing ones, altering established neural connections and disrupting circuits that store old memories. Much of this early wiring is eventually "pruned," leading to memory loss.

Before age seven, this "turf" among neurons is especially intense. By age seven, the hippocampus stabilizes its connections, enabling the retention of episodic memories.

Can Childhood Memories Be Recovered?

Recovering lost childhood memories seems unlikely. Pruned neural connections cannot be restored, and surviving memories may be distorted over time. In a 1995 experiment, researchers shared childhood stories—some real and one fabricated—with participants. Despite being told that one story about getting lost in a mall at age five was false, 25% of participants believed it to be true. Even after learning the story was fabricated, some remained convinced of its authenticity, suggesting that early memories may contain elements of fantasy or borrowed narratives.

Because of ongoing neurogenesis, it’s nearly impossible to prevent childhood memories from fading. However, this neural plasticity is what enables young children to exhibit remarkable learning and memory skills.

While the loss of childhood memories may feel like a drawback, it’s a trade-off for the brain’s incredible adaptability and capacity for growth.