Is it possible to learn while you sleep?

A friend of mine has been asking me for a while to write a blog on learning in your sleep. To be honest, when he first suggested this, I laughed. I thought it was a ridiculous idea. What was he thinking? Should I go to bed every night with a volume of Encyclopaedia Britannia under my pillow? After a month I will have absorbed all this knowledge then I can make my fortune on Millionaire! But my friend kept encouraging me to write about learning while sleeping, so finally I’ve done some research, and I will admit that I’m surprised by what I’ve discovered.

A French man and his dreams …

From the articles I’ve read on this subject, I’ve learnt that you cannot learn new skills in your sleep, but you can consolidate or reinforce some knowledge while you slumber, usually through sound. I read around 30 articles on this subject, but the most informative and well-written was a piece published on the BBC website, ‘Can you learn in your sleep?’  This article included some wonderful science history, in particular the story of the 17^th-century French aristocrat, Marquis d’Hervey de Saint-Denys. Basically this man just wanted to have great dreams. For his first experiment, he painted a very immodestly dressed woman while chewing on an orris root (the root of an Iris plant). That night he asked his servant to place a piece of the root in his mouth, and yes the taste of the root prompted him to see the scantily dressed woman in his dream. Another time he asked an orchestra to play a certain waltz whenever he danced with desirable women. He then rigged up a music box to play those tunes while he slept and again he dreamt he was with good looking women. Marquis d’Hervey de Saint-Denys then wrote a book about his experiments, Dreams and How to Guide Them.

Marquis d’Hervey de Saint-Denys was really just focussed on having good dreams, but his approach was to trigger the sleeping brain to revisit certain memories – this is the key to learning or at least reinforcing information while you sleep.

Smells trigger memories in sleep

Susanne Deikelmann from the University of Tubingen in Germany has been researching sleep learning. She made her research subjects learn a game of setting out specific patterns with objects in a grid before going to sleep in her lab. Some of the subjects were exposed to a subtle odour as they played the game. Diekelmann then wafted the same scent into their noses as they slept. Brain scans showed that these subjects’ brain had greater communication between the hippocampus and several cortical areas, compared to those without the smell cue. This inter-brain area communication improves memory. You see, deep sleep is critical to memory. During deep sleep our brains moves our memories from the short-term section to the long-term. So the people who smelt the odour in Deikelmann’s test remembered 20 per cent more pattern than the other test subjects.

Sound triggers memories in sleep

It’s not just smells that help memory. Sound can also trigger recall, provided you do not wake up in the process. Bjorn Rasch at the University of Zurich, Switzerland found that speakers learning Dutch, remembered 10 percent more vocabulary if they listened to the foreign words on a CD at night while asleep. A 2012 US study also found that people were more likely to correctly play a melody if played to them in their sleep.

High-tech intervention while we sleep

As we slumber we experience different types of sleep. During the first half of the night, we go into slow-wave sleep. This is when we basically sort out our memories, moving information from the day from our short-term brain folder to our long-term brain folder. When we are in slow-wave sleep mode, the firing of our brain cells is very synchronised. Electrodes attached to the scalp show slow-wave sleep as slow, high-amplitude oscillations. People with insomnia, who experience less slow-wave sleep than normal sleepers, often have impaired memory. Scientists have investigated whether it’s possible to enhance slow-wave sleep. In 2004, Jan Born, also from the University of Tubingen, found that he could stimulate or amplify brain signals by sending a small electric current across the skull. He saw his subjects’ verbal memory improve after sending a small electric current across their skulls. Another experiment showed that headphones which send sounds in synch with slow-sleep brain waves improved memory.

 Do you fancy going to sleep wearing headphones or electrodes attached to your head?

Inducing slow-wave brain activity while awake

Another researcher is looking at ways to induce slow-wave brain activity while we are awake. Miriam Reiner at the Technion Institute of Technology in Haifa, Israel believes that we should teach our brains to move into slow-wave activity immediately after we have learned something new. In her study, an electrode is attached to a subject’s head and feeds into a computer game. Through this experiment she induces the right speed of brain wave for memory consolidation. She says this gives the brain a head-start when it comes to reorganising the day’s events during night sleep.

What are the side effects?

Needless to say, more trials are needed before any of these techniques are recommended, so don’t start hooking yourself up to electrodes as you sleep! Also the experts have not even started looking at side effects. If you enhance one memory, will it diminish another? You might be able to quickly learn a foreign language, but what if you forget your name or where you live?

I would be willingly to listen to a piece of music that I’m trying to learn on the guitar as I sleep. I love playing the guitar. I already speak Italian and English but if I was going to learn some French I’d also be prepared to listen to French words as I slept.

My problem is that I’m really sensitive to noise as I fall to sleep. I hate dripping taps however according to the research I do need to listen during the first half of the night. I would need to set up a timer or get someone to start a CD playing after I fall to sleep. This all sounds a bit high-tech and challenging. I can’t promise that I’ll get around to doing any personal experiments on whether sleep-learning works for me!

Be slow to dismiss the ideas of others!

Perhaps the one lesson I have learnt from writing today’s blog, is that I should be more open to my friends’ suggestions. My friend told me that I should write something on sleep-learning and for six months I scoffed at the idea, and yet there is some scientific basis to sleep-learning. I’ve learnt that I should be very slow to disregard other people’s ideas, even if they seem a little crazy at first! Many good ideas seem crazy at first.