Study shows that we actually can learn language while in deep sleep
Many studies have proven the link between sleep and memory consolidation, showing that sleep helps strengthen newly formed memories.
Researchers continue to unravel the mysteries of sleep and why we do it, but one of the bigger questions that comes from this research is whether or not we can learn new things during deep sleep.
Sleep is considered unproductive time, and it has been thought that the brain is detached from the physical world during deep sleep. But a new study conducted by researchers from the University of Bern in Switzerland challenges this long-held notion.
In a new study published in the journal Current Biology, researchers were able to show for the first time that while asleep, the brain can learn foreign words and associate their translations with associations stored into wakefulness.
This means that the brain may be capable of storing and processing new information during certain stages of deep sleep.
The new study is part of an interdisciplinary research project called Decoding Sleep, the aim of which is to understand sleep and cognition. Previous studies have proven that sleep can help strengthen newly learned information and this information is re-played during different sleep stages.
Knowing this, the Bern researchers felt it only made sense that the brain should be able to process new information during sleep as well.
To test this hypothesis, the researchers played recordings of a word from an artificial language and its translation in German during the “Up-state” stage of deep sleep of a sleeping participant.
During deep sleep, the brain cells are active for a brief period called the “Up-state” which is followed by a short period of inactiveness called “Down-state.” Our brain alternates between the two states every half second during deep sleep.
The researchers played a word pair (the fake word and its translation) during the different states and found that if a pair was played two to four times during the Up-state of deep sleep, participants were later able to recall the word association of newly learned terms while awake.
For example, if a sleeping participant heard the word “guga” and its translation “elephant” over and over again while asleep, when awake, the participant was accurately able to associate the word guga with something large.
“It was interesting that language areas of the brain and the hippocampus – the brain’s essential memory hub – were activated during the wake retrieval of sleep-learned vocabulary because these brain structures normally mediate wake learning of new vocabulary,” said Marc Züst, the co-first-author of the new study. “These brain structures appear to mediate memory formation independently of the prevailing state of consciousness – unconscious during deep sleep, conscious during wakefulness.”
Playing the words in the Up-state stage of deep sleep was key, and the researchers say their results challenge the theory that we can’t learn in our sleep.