New research suggests that the age-old question of whether our waking lives and dreams are connected can now be answered.

A team at Swansea University, led by Professor Mark Balgrove, found that two key factors influenced quality of learning: sleep, and motivation. After teaching stories to volunteers who had to remember them after a period of 2 hours of either sleep or wake, the researchers found volunteers who slept remembered more of the stories than those who were awake.

The mechanism through which sleep improves our memory is subject to a lot of research world-wide but Professor Blagrove’s group has recently taken another leap forward by also studying the emotional aspect of learning. Professor Blagrave explains how they did the first ever test of somebody’s intrinsic value of what they have learnt.

“We taught Welsh words to English newcomers to Swansea and we also asked them how much they value or don’t value the language and what we found was that there was a relationship between the more valued the language the bigger was the improvement across the sleep and your amount of value didn’t affect how well you learnt it was the change across sleep [that was affected]. That shows that your level of motivation for things can affect what your sleep does to your memories,” he said.

The observation that emotions have an impact on how our memories are stabilised and processed in our sleep ties in well with the group’s previous research, and provides important information to help scientists weigh up current theories about why we dream at all.

One controversial theory claims that, rather than dreaming helping us to learn, it's in fact the mechanism of processing events and forming memories that causes us to dream in the first place. There is evidence against this theory, that our memory may improve even in dream-less sleep phases. On the other hand, the ‘dream-lag effect’, or when we dream about a waking event 5-7 days after it took place, may provide evidence that dreams reflect what our brain is doing.

Scientists have also found that we rarely re-play full events in our dreams, which led to a theory claiming that dreaming is a cognitive activity we develop over time, and our dreams are characterised by our ability to understand metaphors. To support this, Professor Blagrave uses the metaphor of seeing love as a journey, as in ‘we have come to a bumpy patch’ or ‘we’re going on separate ways’. In our dreams, instead of dreaming about the sentence of ‘a bumpy patch’ we might dream of being in a car, shaking

“You are having a metaphorical dream that takes quite literally your waking life as the metaphor but in your dream you are actually having the concrete experience” he adds.

Dr Petra Szilagyi is an Axa Media Fellow, placed at Nature News. She is a Senior Lecturer at the Department of Pharmaceutical, Chemical & Environmental Sciences at the University of Greenwich.