Our memories of childhood have become fuzzy over time, and researchers are now investigating why this happens. The phenomenon is known as “infantile amnesia,” where memories formed before the age of 4 seem to vanish as we grow older.
The explanation may lie in our brain’s ability to form long-term memories. While it’s thought that these systems aren’t fully developed until children reach 4, a recent animal study on mice suggests this might be more complex. The researchers discovered that memories exist, but are not accessible until triggered.
A new study using MRI technology found that human infants show signs of memory activity as early as 1 year old. This implies that the results in mice may also apply to humans.
In mice, infantile amnesia has been extensively studied due to their sophisticated genetic tools. Researchers recently conducted experiments where young mice were taught to associate a light with a mild shock. When left alone, the association was forgotten due to infantile amnesia. However, by manipulating a specific gene that codes for a protein modifying DNA, researchers found they could make these memories permanent.
The discovery provides new insights into human memory formation and may shed light on why our childhood memories become hazy over time.
Source: https://arstechnica.com/science/2025/03/infants-can-form-memories-starting-at-1-but-they-dont-last-until-later