When we get the right amount of sleep each night there are a host of benefits for our bodies: it recharges our biological batteries, boosts memory and mood, and could even reduce the risk of serious diseases. But is it possible to learn new things while we're dozing?
Investigations into sleep learning began as far back as 1956, when volunteers were played recordings of facts while they slept. Upon waking, none of the participants could remember anything of the facts they'd heard. Case closed? Not quite, because the research that's been carried out since makes the issue rather more complicated.
One study from last year found students were better able to recall foreign words after they'd heard them in their sleep, while another piece of research was able to find a link between smells, sleep, and learning - though how much the sleep itself was responsible isn't completely clear.
Over at The Guardian, neuroscientist Jordan Lewis believes the act of sleeping is helpful in reinforcing what we've learnt throughout the day - but he doesn't think we can take in new information while we're at it. Current scientific theories suggest the slow waves passing through our brains as we sleep act as an echo chamber for the memory data we took on board while we were awake.
"Slow-wave or deep sleep has been recognised for some time as critical for memory consolidation - the stabilisation of memory from short-term to long-term," says Lewis. "During slow-wave sleep, which tends to happen during the first half of the night, the firing of our brain cells is highly synchronised. When we measure sleep using electrodes attached to the scalp, slow-wave sleep appears as slow, high-amplitude oscillations."
Or perhaps it just depends how far you're prepared to go to learn something new overnight. Back in March, a group of French researchers were able to manipulate the memories of sleeping mice - they artificially boosted the positive feelings associated with a certain place while the mice were dozing, and upon waking, the mice wandered straight back to the location in question.
This shows some form of memory manipulation is possible, but unless you're a mouse - and you're prepared to fit electrodes to your head each night - you should probably treat those 'learn while you sleep' claims with a fair amount of caution for now. "Our brains have developed a pretty clever mechanism for helping us learn new information," concludes Lewis. "Be kind to your noggin and give yourself enough sleep to take advantage of it."