- Many people’s earliest clear memories are of events that occurred when they were about 3 years old. However, a new study indicated humans can begin forming memories much earlier than that.
- Researchers said “infantile amnesia” is likely related to the hippocampus and the way various regions of it mature.
- However, it remains unclear why the memories do not persist into adulthood.
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What is a person’s earliest vivid memory? For most people, it’s something that happened when they were about 3 or 4 years old.
Before then, people usually remembered most of what they had learned during those years, like how to talk and who their family was, but not specific events.
That phenomenon is known as “infantile amnesia,” and there may be a scientific reason for it.
What do researchers know about making memories?
For a long time, scientists have believed people don’t hold on to experiences because the hippocampus — the part of the brain responsible for saving memories — is still developing.
However, new research from Yale University suggested that the phenomenon might not be the problem.
What have scientists discovered?
Researchers examined a group of infants aged 4 months to 2 years. They showed the infants pictures they’d never seen before, then showed them one of the images they had previously seen next to a new one.
Using functional magnetic resonance imaging (fMRI), researchers found the greater the activity in a baby’s hippocampus when looking at the image for the first time, the longer they looked at it the second time — signaling that they recognized it.
They also found that the part of the hippocampus where encoding was strongest was the same area linked to episodic memory in adults, and children older than 12 months exhibited the strongest reaction. Episodic memory is remembering specific events.
Before now, scientists had only found evidence that the hippocampus in infants as young as 3 months old displayed a type of memory called “statistical learning,” which is recognizing patterns.
Why don’t people remember being babies?
These two types of memories use different neuronal pathways in the hippocampus. Past studies have shown that the statistical learning pathway develops earlier than the episodic memory pathway.
So, while this new study showed episodic memories can be encoded by the hippocampus earlier than scientists thought, it did not explain why they don’t last into adulthood.
The scientists behind this study continue to research to determine that.
