No matter how hard people try, they cannot recall details from early childhood. A new study published in the journal Science shows that the reason is not the absence of memories, but rather the impossibility of retrieving them as one grows older.
In the study, scientists tested 26 infants ranging from 4 to 25 months old. During the experiment, the infants were placed in an MRI machine, where they were shown a series of unique images for 2 seconds each. The researchers aimed to record the activity in the hippocampus, which is related to emotion, memory, and the autonomic nervous system.
Shortly after, the infants were shown two images side by side: one was familiar, and the other was unfamiliar. By tracking the infants' eye movements, the researchers noted which images received longer attention.
If an infant looked longer at the familiar image, it indicated that the memory had been retrieved. If they did not look at either image for long, it likely suggested that the memory was less developed.
After collecting initial data, the team analyzed the MRI scans of the infants who looked longer at the familiar image and compared them with those of others.
While it remains unclear why memory encoding appears more pronounced in infants over 12 months, it is likely related to significant changes in the body.
The researchers are actively working to understand why the brain cannot retrieve these early memories, but they speculate that the hippocampus does not receive specific "search queries" to locate memories, as these are stored based on the child's early experiences.
