IN THE film Inception, Leonardo DiCaprio plays a dream architect who enters sleepers’ subconscious minds and manipulates their dreams. The idea of dream control quickly caught public imagination and the film became a huge hit. But that was fiction. Is it really possible to direct someone else’s night-time wanderings? I set out to answer that question with the Dream:ON project, which used people’s smartphones to subtly manipulate their dreams as they slept. Half a million people subscribed, allowing us to track the patterns of their dreams in unprecedented detail – with results showing that the forces shaping our nocturnal life are even more mysterious than I had imagined. The idea of manipulating dreams has a long history. About 150 years ago, one of the first dream researchers, the Marquis d’Hervey de Saint-Denys, found he could prime his sleeping mind. During one trip to the south of France, for instance, he wore the same perfume every day, before sealing the bottle on his return. Months later, he asked his servant to sprinkle the perfume on his pillow on random nights. As he expected, on those nights the landscape of his travels was more likely to enter his dreams (New Scientist, 21 December 2013, p 48). Although it was pioneering work, the Parisian nobleman’s research largely consisted of self-experimentation. In 1899, US physiologist James Leonard Corning took a more systematic approach with his “dream machine”. Volunteers were invited to lie on a couch with a leather helmet secured to their head. Resembling the gear now used by amateur boxers, the helmet was designed to hold metallic saucers over the volunteer’s ears. Lengths of rubber tubing connected the saucers to a nearby Edison phonograph, and during the night Corning piped various pieces of classical music to the volunteers. Corning claimed that his remarkable device could help those suffering from nightmares, and described how one man’s “carnival of the horrible” was transformed into “agreeable visions” after just a handful of sessions. In another instance, the procedure helped cure a woman’s melancholy, although she also Golden slumbers: can sweet sounds send you to a pleasant place? For two years, psychologist Richard Wiseman has been trying to sculpt thousands of people’s dreams. Did he succeed? exhibited “a striking gain in appetite” that culminated in “a small though decided accession of weight”. Although years ahead of his time, Corning had no way of knowing when his volunteers were dreaming, and so trying to play the music at the right time was problematic. Faced with this seemingly insurmountable challenge, he eventually lost interest. It wasn’t until the 1950s that Eugene Aserinsky at the University of Chicago discovered “rapid eye movement” sleep – a stage in which the eyes dart in their sockets, while the rest of the body remains almost completely paralysed. Recordings from electrodes placed on the scalp also suggested it was a time of intense neural activity. Importantly, whenever Aserinksy woke someone up during REM sleep, they were almost always dreaming. Aserinsky’s findings revolutionised sleep science because it allowed researchers to time when they woke their subjects to elicit dream reports. It also rekindled an interest in dream control. In the early 1960s, for example, Stanford sleep scientist William Dement invited volunteers into his laboratory, waited until they entered REM sleep, and then either played a tone into their ears, shone a bright light onto their face or sprayed them with water. He then waited 10 minutes, woke them up with a loud dinner bell, and had them describe their dream. About half of the participants incorporated the stimuli, with, for instance, the water resulting in dreams about sudden rainfall, the tone triggering images of an explosion and the bright light producing reports of an outbreak of fire. Despite these positive results, researchers had no way of using these techniques outside the laboratory and so interest in dream control waned again. But a few years ago, I realised that the ubiquitous smartphone offered a chance to test the idea on an unprecedented scale. I contacted an app development company and suggested that we conduct a large-scale experiment into dream control – and Dream:ON slowly took shape. The idea is simple. Before going to sleep, a person sets an alarm on their smartphone and selects a specially prepared soundscape, such as a walk in the countryside, which includes “ A spray of water triggered dreams about sudden rainfall” the sound of the breeze rustling through the trees, or a visit to the coast, represented by waves gently lapping at the shoreline. (Users could also download additional tracks at a small cost.) They then place their smartphone on their mattress and go to sleep. The app works by targeting the final REM period in the sleep cycle. About 30 minutes before the alarm, the smartphone’s accelerometers become active, measuring the sway of the mattress as someone turns in their sleep. When the phone detects that the person has stopped moving – suggestive of the body paralysis that comes with REM sleep – the app gently plays their chosen soundscape. Once awake the person is then prompted to submit a description of their dream. Dial your destination Dream:ON was launched in the UK at the 2012 Edinburgh International Science Festival. From the 500,000 people who have now downloaded the app, we have collected tens of thousands of dream reports – a vast catalogue that has itself helped us to investigate the natural cycle of people’s dreams (see “The dark side of the moon”, page 50). And in line with previous research, we also found a correlation between the soundscapes people chose and their subsequent dreams. If someone chooses the countryside landscape they tend to experience dreams that involve greenery, flowers and meadows; when they select the beach soundscape they are more likely to be transported to the coast, and suddenly feel the sun beating down on their skin. But is this enough evidence to show that outside cues influence our dreaming? An alternative explanation is that having themselves decided what they would like to dream, they primed their sleeping mind. To test that possibility, the app sometimes didn’t play a soundscape even though someone had chosen one. Even then, many still dreamed about the scenery of their chosen soundscape, which seems to show that suggestion is an important factor in determining our dreams. But perhaps that doesn’t matter: whatever the mechanism, we have helped people shape their dreams. Excitingly, the work suggests that it might
THE DARK SIDE OF THE MOON
People have long associated a full moon with all manner of strange behaviours. Indeed, the term “lunatic” is derived from the Latin word for moon. But although there is little evidence that the moon shapes our waking actions, it may influence our sleep. In 2013, neuroscientist Christian Cajochen at the University of Basel in Switzerland decided to take a scientific look at this rather strange idea by reanalysing the data from several experiments that had been conducted in a sleep laboratory. During these studies, volunteers were connected to an EEG machine and had their sleep monitored throughout the night. Cajochen looked at the date of each session, figured out where it fell in the lunar cycle and then plotted this against volunteers’ sleeping patterns. He found that around the time of a full moon, people slept about 20 minutes less, took approximately 5 minutes longer to fall asleep, and experienced 30 per cent less deep sleep throughout the night (Current Biology, vol 23, p 1485). It isn’t clear how the sleepers were sensing the lunar cycle. They couldn’t see the moon from their bed, so Cajochen speculates that higher light levels on the way into the lab might have subtly changed the rhythm of their body clock. That’s not to say the lunar rhythm didn’t have an evolutionary purpose lighter sleeping patterns around the time of a full moon may have helped our predecessors guard against predators who were able to see more clearly in the moonlight, he says. Fascinated by these findings, I examined whether the lunar cycle also influenced dreams. I randomly selected a few hundred dreams from the Dream:ON database and had them rated for bizarreness between “1” (such as a man walking into a bar and having a quiet drink) to “7” (a horse walking into a bar and suddenly turning into a hot air balloon). Plotting these ratings against the lunar cycle, I was surprised to find that people were indeed having more bizarre dreams around the time of a full moon. It’s a preliminary result, and our work is now focusing on the explanation for the effect: whether people are simply more anxious when they see a full moon or if their lighter sleep patterns are affecting their dreams in some way. now be possible to use this effect to help people in their waking lives. Around 80 per cent of dreams involve some sense of anxiety. Most sleep scientists believe that these negative scenarios aren’t designed to terrify you, but rather to help you cope with your everyday concerns and worries. Various versions of this “dreams as nocturnal therapist” theory have been proposed. Some researchers believe that negative events lose their emotional impact when they are experienced repeatedly, and speculate that dreaming about them might lessen the trauma. Others suggest that dreams help you cope with a present-day problem by replaying past events that evoked similar emotions. Regardless of the exact mechanism, all of the theories predict that on any one night your initial dreams will tend to focus on your anxieties. Then, as the night wears on, the emotional impact is reduced, resulting in calmer dreams that cause you to wake in a better mood – a pattern that has been confirmed by Rosalind Cartwright at Rush University Medical Center in Chicago (Psychiatry Research, vol 81, p 1). The theory may also provide an intriguing insight into depression. Sleep scientists have known for some time that the dreams of those diagnosed with depression are long, frequent and negative. As a result, people often wake up feeling sad and distressed. The nocturnal therapist theory suggests that this unusual pattern of dreaming may be the result of their sleeping brains going into overdrive in an attempt to resolve their anxieties and worries. Pursuing this idea, Cartwright monitored the dreams of people diagnosed with depression following a difficult divorce. She discovered that those who experienced increasingly positive dreams across the night were more likely to have recovered from their depression a year later. Those whose dreams became progressively more anxious were more likely to continue showing symptoms (Psychiatry Research, vol 51, p 245). So if it is possible to change the content and emotional tone of people’s dreams, can they be directed to help someone work through his or her anxieties? It’s a bold and exciting idea. Over a hundred years ago Corning speculated that his dream machine could help change people’s lives. The time has come to find out whether he was right. ■
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