The Role of Sleep in Learning New Words

Sep 11, 2009 by Lin Edwards weblog
A child sleeping (Sleep)
A child sleeping. Image: Alessandro Zangrilli, via Wikipedia.

(PhysOrg.com) -- A new study has demonstrated for the first time the importance of sleep in learning new words, and has shown the process has fast and slow components. The slow component is associated with sleep.

Professor Gareth Gaskell, Professor of at the University of York, described the study on acquiring vocabulary in a talk at the British Science Festival 2009 on 8 September 2009. He explained that when we encounter a new word, a memory representation of the word is formed immediately in the hippocampus region of the brain. This is the fast component of vocabulary acquisition.

The memory of the novel word is retained during the day, but during a slow process occurs, in which the memory representation of the word is fed to the neocortex, where it is compared with other words we know. This process integrates the word into our vocabulary and changes the memory representation, making the word more recognizable and easier to recall in future. Professor Gaskell said the integration process is likely to continue over time, possibly even over years.

Scientists have known for some time that words are recognized in a process in which they are compared with those we already know. So for example we only recognize the word cathedral when similar words (like catharsis) are ruled out. This means that when the new words are fully integrated, they slow down recognition of similar existing words, and time taken can be measured.

In the latest research, Gaskell and his team studied 64 adults, split into two groups. One group was taught the invented words at 8 am, while the second group learned them at 8 pm. They tested the groups immediately afterwards, and after 12 and 24 hours.

The results showed the group that had learned the new words at 8 pm were able to integrate them into their vocabulary better than the group who had been awake for the 12 hours before testing. After 24 hours, when both groups had slept, there was no difference. Gaskell concludes that sleep or a brain state associated with sleep is able to induce integration of new words into the vocabulary.

Another finding from the study was that the group who learned words at 8 pm had better recall of the new words after 12 hours, and improved further after 24 hours, while the group that learned words in the morning tended to have slightly worse recall 12 hours later, but improved during the night.

Professor Gaskell thinks vocabulary exists as representations of words across thousands of neurons in the of the brain. Distributed storage of words makes the system more robust to damage, and allows the stored information to be used with flexibility, but it also makes it difficult to integrate new words into the mental lexicon quickly. An earlier study by Jay McClelland suggested the has a second type of memory, which is more concentrated, and can incorporate new information quickly. This form of memory is centered on the hippocampus.

Professor Gaskell said that learning a language is something everyone does, and in many countries almost everyone is fluent in more than one language. We continue to learn new words throughout our lives, so the study is relevant to all of us. The research could also have implications for people with amnesia (who usually find it difficult to learn new words), sleep disorders, or conditions such as autism that often disrupt sleep patterns.

The study suggests learning new words in the evening is more effective than learning them early in the day because our brains use the "downtime" of sleep to integrate the new words. So reading a book at bedtime may be a great idea if you want a good vocabulary.

© 2009 PhysOrg.com

Explore further: Impact of childhood bullying still evident after 40 years

add to favorites email to friend print save as pdf

Related Stories

Sleep enforces the temporal sequence in memory

Apr 18, 2007

We have usually quite strong memories of past events like an exciting holiday or a jolly birthday party. However it is not clear how the brain keeps track of the temporal sequence in such memories: did Paul spill a glass ...

Turn off TV to teach toddlers new words

Jun 28, 2007

Toddlers learn their first words better from people than from Teletubbies, according to new research at Wake Forest University. The study was published in the June 21 issue of Media Psychology.

Recommended for you

Our brains are hardwired for language

12 hours ago

A groundbreaking study published in PLOS ONE by Prof. Iris Berent of Northeastern University and researchers at Harvard Medical School shows the brains of individual speakers are sensitive to language univer ...

Child burn effects far reaching for parents

17 hours ago

Parents of burn victims experience significant psychological distress for at least three months after the incident and may compromise the post-operative recovery of their child, WA research has found.

Internet use may cut retirees' depression

17 hours ago

Spending time online has the potential to ward off depression among retirees, particularly among those who live alone, according to research published online in The Journals of Gerontology, Series B: Psychological Sciences an ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Diotrephes
3 / 5 (1) Sep 11, 2009
An interesting follow-up to this study would be a test of memory following brief power naps of say 15 to 20 minutes.

I wager they'd receive close to or identical results as the evening group.

One could even study precisely how much nap time would be required to compete with the evening group.

More news stories

Leeches help save woman's ear after pit bull mauling

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

Venture investments jump to $9.5B in 1Q

Funding for U.S. startup companies soared 57 percent in the first quarter to a level not seen since 2001, as venture capitalists piled more money into an increasing number of deals, according to a report due out Friday.

White House updating online privacy policy

A new Obama administration privacy policy out Friday explains how the government will gather the user data of online visitors to WhiteHouse.gov, mobile apps and social media sites. It also clarifies that ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.