Have you ever wondered why your earliest childhood memories begin around age three or four, with everything before that seemingly lost to time? A pioneering study from Yale University has uncovered fascinating insights into how infant brains form memories, challenging long-held assumptions about early cognitive development. The research reveals that babies do create memories during infancy, but these memories become inaccessible as we age due to fundamental changes in brain development.
Published in the journal Science, this groundbreaking study utilized innovative brain imaging techniques to observe memory formation in real time within the developing brains of infants. The findings not only demonstrate that babies possess sophisticated memory capabilities much earlier than previously understood but also provide clues about why these early memories remain elusive throughout our lives.
The 3 key discoveries about infant memory
Memory formation begins before verbal skills develop: The research team examined 26 infants ranging from 4.2 to 24.9 months old, dividing them into two age groups: those younger than 12 months and those between 12 and 24 months. Through careful observation and advanced brain imaging, the researchers confirmed that memory formation occurs well before children develop language skills that would help them verbalize or contextualize their experiences.
This finding contradicts the common assumption that memories require language to form. Instead, the study demonstrates that preverbal infants actively encode experiences and can recognize familiar stimuli, even without possessing the vocabulary to describe what they observe. This preverbal memory system appears to work differently from the verbal memory systems that develop later in childhood.
The hippocampus undergoes significant development around age one: Perhaps the most significant finding involves the timing of brain development. The study revealed a marked difference in hippocampal activation between babies younger and older than 12 months. The hippocampus, a deep brain structure essential for memory formation, showed notably stronger activity in older infants when they encountered and encoded new information.
This developmental milestone around the first birthday correlates with significant neurological growth. According to the lead researcher, Dr. Nick Turk-Browne, professor in the department of psychology at Yale University, this period coincides with rapid anatomical growth of the hippocampus and numerous other perceptual, linguistic, motor, and biological changes. This surge in development apparently establishes more sophisticated memory-encoding mechanisms that persist into adulthood.
Memory-related decision making requires the orbitofrontal cortex: The third major finding concerns how infants process and make decisions about remembered information. The research showed that only older infants demonstrated activity in the orbitofrontal cortex when viewing familiar versus new images. This brain region plays a crucial role in memory-related decision-making and recognition processes.
This discovery suggests that while younger infants may form basic memories, they lack the neural mechanisms to make complex decisions based on those memories. The development of the orbitofrontal cortex connection represents a significant advancement in how babies interact with their remembered experiences, allowing for more sophisticated cognitive processing of familiar information.
The innovative methodology behind the discoveries
Studying infant brain activity presents unique challenges that the Yale research team overcame through creative experimental design. The researchers placed babies in a functional magnetic resonance imaging machine and showed them a series of unique images for two seconds each while recording hippocampal activity.
The research required developing entirely new approaches for conducting memory experiments with infants inside an MRI machine. As Dr. Turk-Browne explained, this type of research has previously been conducted mostly while infants were asleep because babies wiggle, cannot follow instructions, and have short attention spans. The team addressed these challenges to capture meaningful data about memory formation in the developing brain.
After a momentary delay, the researchers showed the babies two images side by side, one familiar from the previous viewing and one entirely new. By tracking the infants’ eye movements, the team could determine which image captured more attention. The fundamental principle behind this approach leverages the natural tendency of babies to look longer at things that interest them, which researchers have used for decades to study infant cognition.
When an infant focused longer on a familiar image, it suggested recognition and memory recall. Conversely, showing no preference likely indicated less developed memory functioning. By combining this behavioral data with the brain imaging results, the researchers created a comprehensive picture of memory development across different age groups.
Why we cannot access our earliest memories
The study provides compelling evidence about why adults cannot recall experiences from infancy, a phenomenon known as infantile amnesia. While the research confirms that babies do form memories, it suggests that these early memories become inaccessible due to fundamental changes in how the brain encodes and retrieves information as we develop.
Dr. Turk-Browne and his team hypothesize that the infant brain processes and stores memories differently than the adult brain. As we grow older, the search mechanisms we use to retrieve memories may not match how those early memories were initially encoded. Essentially, our adult brains cannot formulate the correct search terms to find memories stored during infancy.
This mismatch occurs because infant experiences are encoded through entirely different perceptual and cognitive frameworks than those used by older children and adults. Without language to label experiences or developed cognitive structures to organize memories, infant memories may remain stored but fundamentally inaccessible to conscious retrieval later in life.
The significance for developmental psychology
This research represents a significant advancement in understanding early cognitive development. Dr. Simona Ghetti, a professor in the department of psychology at the University of California, Davis, who was not involved in the study, acknowledges that while previous research has demonstrated infants’ ability to encode memories, this study uniquely connects memory encoding to hippocampal activation.
Dr. Lila Davachi, a professor in the department of psychology at Columbia University, also not involved in the study, noted the remarkable achievement of demonstrating hippocampal encoding processes in babies for stimuli that seem relatively unimportant to them. This suggests that infant memory systems may be more sophisticated and active than previously understood, encoding information regardless of its apparent significance.
The findings challenge longstanding assumptions about when memory capabilities develop and how they function in preverbal children. By demonstrating that even very young infants possess working memory systems, albeit different from those of adults, the research expands our understanding of early brain development and cognitive processing.
Implications for parents and caregivers
These discoveries hold practical significance for parents wondering how their interactions with infants might influence development, even if the specific memories remain inaccessible later. The research suggests that experiences during infancy do matter significantly, as babies are actively forming memories and learning from their environments.
Ghetti encourages parents to recognize the importance of infancy as a period of enormous learning, even without later memory access. During this critical developmental window, babies learn language by associating sounds with meanings, form expectations around family members, and study properties of objects and the world around them.
The research also explains why repetition proves so effective with infants. Parents often notice that singing the same songs or reading the same books elicits recognition responses from babies. Davachi notes that using repetition with babies strengthens the connection between parent and child because it leverages the developing memory systems highlighted in the study.
The future of infant memory research
This groundbreaking study opens numerous avenues for future research into early cognitive development. Dr. Turk-Browne and his team continue investigating why the brain cannot retrieve early memories later in life, focusing on the specific mechanisms that render infant memories inaccessible to adults.
Future research might explore how different types of experiences create stronger or weaker memory traces in infancy and whether certain experiences might remain more accessible than others. The relationship between emotional development and memory formation also presents a promising area for investigation, potentially explaining why some traumatic or highly emotional early experiences may influence behavior even without conscious recall.
As brain imaging technology advances, researchers may develop even more refined techniques for studying infant cognition without the challenges of movement and attention span that currently complicate such research. These advancements could provide unprecedented insights into how the earliest experiences shape cognitive development throughout life.
The Yale study represents a significant leap forward in understanding the mysterious world of infant cognition. By demonstrating that babies form memories they cannot later access, the research explains the universal experience of infantile amnesia while highlighting the remarkable learning capabilities present from the earliest stages of life. Though we may never consciously remember our infancy, this research confirms that these formative experiences help build the cognitive foundations that shape who we become.
