Infantile amnesia, also known as childhood amnesia, is the inability of adults to recall episodic memories from the first few years of life, typically before the age of two to four. This phenomenon is characterized by a scarcity or absence of autobiographical memories from early childhood, despite evidence that infants and young children are capable of forming memories.
Infantile amnesia refers to the relative absence of recall, by adults, of personal memories that occurred before the ages of 3 or 4.1 This term does not indicate a complete lack of memories but rather a scarcity or fragmentation of memories from infancy, particularly between the ages of 2 and 6.2 On average, this fragmented period wanes off at around 4.7 years, with autobiographical memory stabilizing around 5-6 years of age.2
The development of the hippocampus, a brain region crucial for memory formation and consolidation, is not complete during infancy, which may contribute to the rapid forgetting observed in early childhood.1 Additionally, high rates of neurogenesis (the formation of new neurons) in the hippocampus during infancy might explain the accelerated forgetting of contextual memories, as the integration of new neurons into existing circuits could destabilize and weaken previously formed memories.12
The development of language skills and a sense of self are critical cognitive factors in the formation and retrieval of autobiographical memories:
Language acquisition, which occurs significantly between ages 2 and 4, is essential for encoding and accessing personal memories.12 Without language, infants may be unable to describe or articulate their experiences, leading to difficulties in recall later in life.2
The emergence of a cognitive self, or the awareness of oneself as a distinct individual, typically develops around 18 to 24 months.34 This sense of self is necessary for organizing and retaining autobiographical memories, as it allows children to relate past experiences to their own personal narrative.12
Infants possess a nonverbal declarative memory system that allows them to recall past events, as demonstrated by deferred imitation studies showing that 14-month-olds can remember and imitate actions after delays of several months.1 However, these early memories may not be retained long-term due to the immaturity of neural structures.1 While implicit memories (skills and conditioned responses) can be retained from infancy, explicit memories (conscious recollection of events) are more susceptible to rapid forgetting during early development.2
Sigmund Freud was one of the first to describe infantile amnesia, attributing it to the repression of early traumatic memories, but this psychoanalytic explanation lacks empirical support.2 Modern perspectives focus on the interplay between neurological maturation, cognitive development, and environmental factors in explaining the phenomenon.12 Despite the inability to recall early memories, experiences such as trauma or neglect during infancy can have lasting effects on cognitive and emotional development.1