The Role of Sleep in the Formation of Long-Term Memory in Infants
Even a short nap after learning may help the youngest human brain form long-term memories. New scientific research shows that during the first year of life, sleep is not merely rest — it is an essential part of the memory-building process.
Who doesn’t enjoy a long and restful sleep? For adults, sleep helps regulate thoughts, restore energy, and maintain emotional balance. It appears that the same principle applies to infants.
Sleep and the Infant Brain: What Is Known?
Scientists already know that sleep:
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Helps consolidate new information in adults
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Enables new approaches to old problems
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Integrates different types of information
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Strengthens memory retention in preschool and school-age children
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Increases connections between nerve cells after learning new skills (in animal models)
However, the effect of sleep on memory in the youngest human minds — infants aged 6–12 months — had long remained insufficiently studied.
How Was the Study Conducted?
Researchers from the United Kingdom and Germany conducted an experiment involving infants aged 6 to 12 months.
In the study, infants were shown a short sequence using a hand puppet:
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A mitten was removed from the puppet’s hand
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The mitten was shaken
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The mitten was placed back onto the puppet
After watching the sequence several times, the infants were divided into two groups:
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Long-nap group – infants who slept for at least 30 minutes within a four-hour window after the demonstration
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Short or no-nap group – infants who slept less than 30 minutes or did not sleep at all
What Did the Results Show?
Four hours later, the infants were shown the puppet again, and their responses were observed.
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Infants who had taken longer naps imitated the puppet’s actions more accurately.
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After 24 hours, the same pattern was observed: infants who had slept after the demonstration better remembered the sequence of removing, shaking, and replacing the mitten.
The findings were published in Proceedings of the National Academy of Sciences, a journal of the National Academy of Sciences.
The researchers concluded that:
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Sleep after learning helps infants form long-term memories
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Sleep protects newly formed memories from interference by subsequent information
The Mechanism of Memory Protection
During sleep, the brain processes and selects information received throughout the day. In infancy, this process is particularly important because the first year of life is a period of intensive learning.
During this time, infants develop:
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Language skills
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Motor abilities
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Social interactions
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Understanding of symbols and gestures
Sleep may create a biological window for stabilizing this information within neural networks.
Is There a Paradox?
Previous research on memory consolidation primarily focused on school-aged children and adults. This study demonstrates that memory consolidation processes are already active at a very early stage of life.
This finding suggests that the infant brain is far more complex and functionally capable than previously assumed.
Practical Implications
The study offers an important message for parents:
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A nap after learning a new skill may be beneficial
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An infant’s sleep schedule may be directly linked to learning efficiency
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Sleep is not merely rest but an active neurobiological process
Of course, these findings do not automatically apply to every situation. However, the research clearly indicates a biological link between learning and sleep.
Conclusion
For infants, sleep is not simply a moment of quiet rest. It is an active process that builds memory, organizes information, and lays the foundation for future learning.
Even in the first year of life, the formation of long-term memory is closely connected to sleep. This once again shows that “sleeping” is not a passive state — it is a productive and essential phase of brain activity.