Jakke Tamminen has plenty of students who do that very studenty thing of staying up all night right before an exam, in the hope of stuffing in as much knowledge as they can. But “that’s the worst thing you can do”, the psychology lecturer at the UK’s Royal Holloway University warns them.

He should know. Tamminen is an expert on how sleep affects memory, specifically the recall needed for language. Sleep learning – another idea beloved of students, in the hope that, say, playing a language-learning recording during sleep would imprint itself into the brain subliminally and they’d wake up speaking Latin – is a myth. But sleep itself is essential for embedding knowledge in the brain, and the research of Tamminen and others shows us why that is.

In Tamminen’s ongoing research project, participants learn new vocabulary, then stay awake all night.

Tamminen compares their memory of those words after a few nights, and then after a week. Even after several nights of recovery sleep, there is a substantial difference in how quickly they recall those words compared to the control group of participants who didn’t face sleep deprivation. “Sleep is really a central part of learning,” he says. “Even though you’re not studying when you sleep, your brain is still studying. It’s almost like it’s working on your behalf. You can’t really get the full impact of the time you put into your studies unless you sleep.” […]

But more critical to Tamminen’s current research – and to sleep’s role in language development more generally – is a non-REM phase of deep sleep known as slow-wave sleep (SWS). SWS is important for forming and retaining memories, whether of vocabulary, grammar, or other knowledge. The interaction of different parts of the brain is key here. During SWS, the hippocampus, which is good at quick learning, is in constant communication with the neocortex, to consolidate it for long term recall.

So the hippocampus might initially encode a new word learned earlier that day, but to truly consolidate that knowledge – spotting patterns and finding connections with other ideas that allow for creative problem-solving – the neocortical system needs to get involved.

This information expressway between the hippocampus and the neocortex is populated by sleep spindles – spikes in brain activity that are no more than three seconds long.

“Sleep spindles are somehow associated with linking new information with existing information,” Tamminen says. And the data from his research participants suggests that people with more sleep spindles have more consolidation of the words they have learned. […]

Children have more slow-wave sleep than adults – which may be one factor explaining how quickly kids learn, in both language and other areas. The child sleep lab at Germany’s University of Tuebingen investigates the role of sleep in consolidating children’s memory. Monitoring what happens in children’s brains during sleep, and how much information they retain before and after sleep, shows that sleep helps with accessing implicit knowledge (procedural memory) and making it explicit (declarative memory).

“The effects are stronger in early childhood because the brain is developing,” says Dominique Petit, the coordinator of the Canadian Sleep and Circadian Network, who has also explored the circadian rhythm in children. In practical terms, this means that “children need to sleep during the day to remember everything that they have to learn”.

“Daytime naps in young children have been shown to be really important for vocabulary growth, generalization of the meaning of words and abstraction in language learning,” she says. “Sleep continues to be important for memory and learning throughout the lifetime, though.” […]

Not only does sleep help with accessing this information, it also changes the way this information is accessed. This makes brains more flexible at retrieving information (or able to access it in more ways).

But it also makes them better at extracting the most significant parts of it.

“It’s actually an active process of strengthening and changing the memory trace,” Zinke says. “Memory gets transferred in a way that the most important information (the gist) is remembered.”

Clearly, for children as well as adults, prolonged sleep isn’t a sign of laziness in a language learner. It’s critical for our brains’ connections and our bodies’ rhythms.

Available at: https://www.bbc.com/future/ article/20180815-why-sleep-should-be-everystudents-priority (adapted)

Read Text I to answer the question:

“Fundamental breakthroughs in the neurosciences, combined with technical innovations for measuring brain activity, are shedding new light on the neural basis of second language (L2) processing, and on its relationship to native language processing (L1). The long-held assumption that L1 and L2 are necessarily represented in different brain regions in bilinguals has not been confirmed. On the contrary, the available evidence indicates that L1 and L2 are processed by the same neural devices. The neural differences in L1 and L2 representations are only related to the specific computational demands, which vary according to the age of acquisition, the degree of mastery and the level of exposure to each language. Finally, the acquisition of L2 could be considered as a dynamic process, requiring additional neural resources in specific circumstances.”

Available at: https://www.sciencedirect.com/science/article/abs/pii/S0959438805000395 (adapted)

Read Text I to answer the question:

“Fundamental breakthroughs in the neurosciences, combined with technical innovations for measuring brain activity, are shedding new light on the neural basis of second language (L2) processing, and on its relationship to native language processing (L1). The long-held assumption that L1 and L2 are necessarily represented in different brain regions in bilinguals has not been confirmed. On the contrary, the available evidence indicates that L1 and L2 are processed by the same neural devices. The neural differences in L1 and L2 representations are only related to the specific computational demands, which vary according to the age of acquisition, the degree of mastery and the level of exposure to each language. Finally, the acquisition of L2 could be considered as a dynamic process, requiring additional neural resources in specific circumstances.”

Available at: https://www.sciencedirect.com/science/article/abs/pii/S0959438805000395 (adapted)

Read Text I to answer the question:

“Fundamental breakthroughs in the neurosciences, combined with technical innovations for measuring brain activity, are shedding new light on the neural basis of second language (L2) processing, and on its relationship to native language processing (L1). The long-held assumption that L1 and L2 are necessarily represented in different brain regions in bilinguals has not been confirmed. On the contrary, the available evidence indicates that L1 and L2 are processed by the same neural devices. The neural differences in L1 and L2 representations are only related to the specific computational demands, which vary according to the age of acquisition, the degree of mastery and the level of exposure to each language. Finally, the acquisition of L2 could be considered as a dynamic process, requiring additional neural resources in specific circumstances.”

Available at: https://www.sciencedirect.com/science/article/abs/pii/S0959438805000395 (adapted)