Summary: New research challenges the idea that infants cannot form memories, showing that babies as young as 12 months old can encode experiences. Using fMRI scans, researchers found that the hippocampus, a brain region critical for memory, is active in infants during a memory task.
These findings suggest that infantile amnesia—the inability to remember early childhood—may be due to retrieval failures rather than an inability to form memories. While humans cannot recall events from their first few years of life, evidence shows that early memories may persist but remain inaccessible.
Key Facts:
- Early Memory Formation: Babies as young as 12 months can encode individual experiences.
- Infantile Amnesia Cause: Memory retrieval failures, not memory formation, may explain early childhood amnesia.
- Hippocampus Activation: fMRI scans confirm that the hippocampus is active during infant memory tasks.
Source: AAAS
Challenging assumptions about infant memory, a novel functional magnetic resonance imaging (fMRI) study shows that babies as young as 12 months old can encode memories, researchers report.
The findings suggest that infantile amnesia – the inability to remember our first few years of life – is more likely caused by memory retrieval failures rather than an inability to form memories in the first place.
Despite infancy being a period of rapid learning, memories from this time do not persist into later childhood or adulthood. In general, humans cannot recall events from the first three years of life – a phenomenon known as infantile amnesia.
Why grown humans have a years-long blind spot in their episodic memory for the period of infancy remains a puzzle. One theory suggests this occurs because the hippocampus, a brain region crucial for episodic memory, is not fully developed during infancy.
However, research in rodents challenges this idea, showing that memory traces, or engrams, are formed in the infant hippocampus but become inaccessible over time. In humans, infants demonstrate memory through behaviors such as conditioned responses, imitation, and recognition of familiar stimuli.
However, whether these abilities rely on the hippocampus or other brain structures remains unclear. In a study using fMRI to scan the brains of infants aged ~4 to 25 months while performing a memory task, Tristan Yates and colleagues aimed to determine whether the hippocampus in infants can encode individual memories.
The memory task, adapted from a well-established method for adults, involved showing images to infants – faces, scenes, and objects – followed by a memory test based on preferential looking, all while undergoing neuroimaging.
The findings show that the infant hippocampus has the capacity to encode memories of individual experiences beginning around 1 year of age, providing evidence that the capacity to form individual memories develops during infancy.
According to the authors, the presence of encoding mechanisms for episodic memory during infancy – despite their ephemeral nature – suggests that infantile amnesia is more likely due to failures in memory retrieval mechanisms.
These insights align with recent studies in rodents, which demonstrate that memories created during infancy can persist into adulthood but remain inaccessible for retrieval without direct stimulation of hippocampal engrams or reminder cues, the authors note.
In a Perspective, Adam Ramsaran and Paul Frankland discuss the study in greater detail.
About this memory and neurodevelopment research news
Author: Science Press Package Team
Source: AAAS
Contact: Science Press Package Team – AAAS
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Hippocampal encoding of memories in human infants” by Nicholas B. Turk-Browne et al. Science
Abstract
Hippocampal encoding of memories in human infants
Humans lack memories for specific events from the first few years of life. We investigated the mechanistic basis of this infantile amnesia by scanning the brains of awake infants with functional magnetic resonance imaging while they performed a subsequent memory task.
Greater activity in the hippocampus during the viewing of previously unseen photographs was related to later memory-based looking behavior beginning around 1 year of age, suggesting that the capacity to encode individual memories comes online during infancy.
The availability of encoding mechanisms for episodic memory during a period of human life that is later lost from our autobiographical record implies that postencoding mechanisms, whereby memories from infancy become inaccessible for retrieval, may be more responsible for infantile amnesia.
