Most of us can’t recall our earliest years, a phenomenon
known as infantile amnesia. A recent study published in Science offers fresh
insights into why these memories elude us, suggesting that babies do form
memories, but accessing them later in life is the challenge. Researchers at
Yale University, led by cognitive psychologist Nick Turk-Browne, used
functional MRI (fMRI) to scan the brains of 26 infants aged 4 to 24 months. The
infants were shown unique images, and their hippocampal activity—a brain region
critical for memory—was monitored. When shown the images again alongside new
ones, babies with higher hippocampal activity during the initial exposure spent
more time looking at the familiar images, indicating memory formation. This
effect was stronger in infants over 12 months, pointing to a developmental
trajectory in memory encoding.
Historically, infantile amnesia was attributed to an
underdeveloped hippocampus, but this study challenges that view, showing that
even young infants can encode episodic memories—specific recollections of
events. So, why don’t these memories persist? Turk-Browne suggests they may
still exist in the brain but become inaccessible due to a mismatch between how
memories are stored in infancy and how we retrieve them as adults. Factors like
rapid neuron growth in early childhood, which disrupts memory circuits, or the
shift from crawling to walking, which alters how experiences are
contextualized, may contribute. Supporting this, a 2023 Science Advances study
on mice showed that early memories could be reactivated in adulthood by
stimulating specific neurons, hinting that human memories might also persist
but remain locked away.
Ongoing research, including Turk-Browne’s work with home
videos from a baby’s perspective, suggests these memories may linger until
around age six before fading. Cultural factors also play a role: studies show
that children in cultures with rich oral traditions, like New Zealand Māori,
recall earlier memories, possibly due to frequent reminiscing with caregivers.
While the mystery of infantile amnesia isn’t fully solved, these findings
highlight that our earliest experiences shape us, even if we can’t consciously
revisit them.