Why can't we remember being a baby?

The phenomenon is called infantile amnesia, and almost everyone has it: most adults have no reliable memories from before about age three, and only patchy ones until around seven.

The old explanation was that infants simply do not form memories. That is now known to be wrong — infants demonstrably learn, recognise faces, and retain information over meaningful periods. The memories form. The question is why they do not persist.

Several factors appear to contribute.

Rapid brain growth. The hippocampus, central to forming lasting episodic memories, is still developing rapidly in early childhood. Research suggests that the high rate of new neuron generation in this period may actively disrupt existing memory traces — new circuits overwriting the connections that held old ones.

Language. Autobiographical memories are largely organised and rehearsed in language. Before a child has the linguistic scaffolding to narrate an event, encoding it in a retrievable form is harder. Memories formed before language often cannot be retrieved afterwards in a verbal format.

Sense of self. Episodic memory requires a concept of a continuous "me" to whom things happened. That develops gradually in the second and third years.

Cultural and conversational effects. Children whose families discuss past events in elaborate detail tend to report earlier first memories, and the average age of earliest memory differs measurably between cultures — which is hard to explain by biology alone.

Many apparent early memories are reconstructions, assembled from photographs and family stories rather than recalled directly. Studies have successfully implanted plausible false childhood memories in adults, so confidence is a poor guide to whether one is real.