How Babies Form Their First Lasting Memories
Unveiling the emergence of long-term explicit memory in infancy
Look into a baby's eyes and you're witnessing the very beginnings of a mind under construction—a consciousness gradually building its repository of personal history. For decades, scientists believed infants were incapable of forming lasting memories for their earliest experiences, a phenomenon known as infantile amnesia. After all, most adults cannot recall events from before they were three or four years old.
Yet groundbreaking research has revealed a startling truth: long before children can speak, and even while their infantile amnesia persists, the architecture for lasting memory is being assembled. The emergence of long-term explicit memory—the ability to consciously recall people, objects, and events—represents one of the most profound cognitive dawnings in human life. This is the story of how developmental psychologists uncovered when and how this extraordinary capability emerges, revolutionizing our understanding of the infant mind 9 .
Unlike procedural memory that allows us to ride a bike without thinking, explicit memory involves the conscious, intentional recollection of facts and events. Think of it as the difference between automatically knowing how to hold a rattle (implicit) versus remembering the specific time your uncle gave you that rattle (explicit) 2 .
Scientists face a unique challenge when studying memory in preverbal infants: how do you ask a baby what they remember? The breakthrough came with sophisticated non-verbal methods like deferred imitation—where an infant watches an adult demonstrate an action and later reproduces it after a delay 6 .
The emergence of long-term memory isn't an overnight phenomenon but a gradual developmental process. Research using deferred imitation and other methods has revealed a clear progression of memory abilities throughout infancy.
Can reproduce simple actions after a day but not after 48 hours 9 .
Can recall information after delays of up to 4 weeks, but not longer 1 .
Can recall actions across context changes and after delays of up to 4 weeks 6 .
Can form long-term memories of one-time events and anticipate sequences; memory becomes more complex and detailed 3 .
How do researchers detect memory in infants who can't yet talk or imitate complex actions? A clever 2017 study published in Scientific Reports used eye-tracking technology to probe the minds of preverbal infants, testing their ability to remember one-time events after a 24-hour delay 3 .
The researchers showed infants aged 6 to 24 months a short, emotionally engaging video. In one clip, an actor in a King Kong costume suddenly emerged from one of two identical doors to attack a human actor.
The next day, the same infants watched the video again while their eye movements were precisely tracked. The critical question was: would the infants anticipate King Kong's appearance by looking at the correct door before he actually appeared?
A second experiment tested memory for objects. Infants watched a different video where a human, after being attacked, grabbed one of two objects (a hammer or a sword) to fight back.
During the second viewing, researchers measured whether infants increased their looking time at the objects before the human grabbed one, and whether they preferentially looked at the specific object that would be used 3 .
| Age Group | Anticipatory Looking to Location | Anticipatory Looking to Object | Interpretation |
|---|---|---|---|
| 6-month-olds | No | Not Tested | Unable to form 24-hour memory of one-time event location |
| 12-month-olds | No | No | Unable to reliably form or express this memory |
| 18-month-olds | Yes | Yes (general) | Can form long-term memory for one-time events |
| 24-month-olds | Yes | Yes (specific target) | More sophisticated memory, including specific object details |
Studying memory in non-verbal subjects requires ingenious methods. The following tools have enabled researchers to make these remarkable discoveries about infant memory.
Precisely measures where and when infants look. Reveals anticipatory knowledge and memory through visual expectation 3 .
Child imitates action sequences immediately and after delays. Measures both immediate recall and long-term retention 5 .
Measures looking time at novel vs. familiar images. Demonstrates recognition memory in very young infants 8 .
Embedding to-be-remembered events in mildly arousing scenarios. Enhances encoding and strengthens memory formation 3 .
These tools have collectively revealed that the infant brain is not a blank slate but an active, learning system that begins forming rich memories long before those memories can be verbally expressed.
The discovery that explicit memory emerges in infancy has profound implications. It highlights the first years of life as a critical period for cognitive development. The hippocampal memory system, vital for forming explicit memories, appears to be "learning how to learn and remember" during this time 2 .
Early experiences, even those not consciously remembered in adulthood, exert a long-lasting influence. Studies of children who experienced severe neglect show that deprivation during early years can lead to significant, sometimes permanent, deficits in cognitive and socio-emotional functioning 2 .
The journey into the beginnings of memory reveals that from the quiet mystery of infancy, a personal past is gradually being built.
Between 9 and 18 months, a remarkable cognitive transition occurs—the dawning of a past that the child can carry forward. This emerging ability to form long-term explicit memories is more than a developmental milestone; it is the foundation of our autobiographical self, the very core of our continuous identity through time.
While the specific memories of infancy may vanish into the fog of infantile amnesia, their legacy remains. They build the neural pathways that allow us to learn, remember, and ultimately, to understand who we are. The silent work of the infant mind, once a mystery, is now being revealed as one of the most active and crucial construction projects of our lives—the building of a memory system that will support a lifetime of learning and experience.