Babies' Brains Make Memories

Brain scans capture memory formation in infants, raising new questions about why people forget their earliest years

- SNICK TURK-BROWNE

A PLUME OF RED, a searing pain and the sounds of summer—these are fragments of my earliest memory, of when I stepped on a glass shard in a Toronto splash park at six or seven years old. I don't remember much from that day, but a scar on my foot bears witness to what happened.

When you ask adults about their first memory of a specific event from their childhood, their answer is typically about something that happened no earlier than preschool. This is true whether you ask a college student or a grandparent, suggesting that adults’ lack of infant or toddler memories is not just the result of normal forgetting that occurs with the passage of time. The lack of autobiographical memory from when you were a baby is known as infantile amnesia.

There are two potential explanations for this phenomenon. One is that infants cannot store memories. The slow development of the hippocampus, a seahorse-shaped region deep in the brain, may be responsible. This region, which is critical for memory, grows and changes throughout childhood, so it might not be available to infants. In this scenario, babies are not so different from people with famous cases of amnesia, such as Henry Molaison and Lonni Sue Johnson, both of whom suffered hippocampal damage in adulthood that made them unable to store memories.