We often think of sleep as a chance to switch off from the outside world, leaving us blissfully ignorant of anything going on around us. But neuroscience research has shown this is a fantasy – we still monitor the environment and respond to particular sounds while we’re sleeping (at least in some stages of sleep) – a fact that will be unsurprising to anyone who has woken up after hearing someone say their name.
Now a study published in Nature Human Behaviour has revealed more about the brain’s surprisingly sophisticated levels of engagement with the outside world during sleep. Not only does the sleeping brain respond to certain words or sounds – it can even select between competing signals, prioritising the one that is more informative.
As every parent knows, gentle rocking helps a baby to fall asleep. Now a new study, published in Current Biology by researchers in Switzerland, shows that a rocking bed also benefits adults, extending the time that they spend in deep, slow-wave sleep, helping them sleep more soundly, and increasing their memory consolidation through the night. A related rocking study on mice, conducted by a team involving some of the same researchers, and published in the same journal issue, helps to reveal how rocking might have these effects.
The last time you and your class-mates or co-workers pulled an all-nighter before a deadline, you may have noticed:there are always those lucky individuals who seem to do just fine after a lack of sleep, while others feel drowsy and confused – almost like they had too much to drink.
New research conducted at the German Aerospace Center suggests this could be because alcohol intoxication and sleep deprivation are more similar than we once thought.
In their study published recently in PNAS, Eva-Maria Elmenhorst and David Elmenhorst and their colleagues show how both affect us via a shared mechanism. And what’s more, if you’re sensitive to one, you’re likely to cope poorly with the other as well.
“I have been lost in a daydream for as long as I can remember….These daydreams tend to be stories…for which I feel real emotion, usually happiness or sadness, which have the ability to make me laugh and cry…They’re as important a part of my life as anything else; I can spend hours alone with my daydreams….I am careful to control my actions in public so it is not evident that my mind is constantly spinning these stories and I am constantly lost in them.”
The 20-year-old woman who emailed these reflections to Eli Somer at the University of Haifa, Israel, diagnosed herself with Maladaptive Daydreaming, sometimes known as Daydreaming Disorder. While Maladaptive Daydreaming is not included in standard mental health diagnostic manuals, there are cyber-communities dedicated to it, and “in recent years it has gradually become evident that daydreaming can evolve into an extreme and maladaptive behaviour, up to the point where it turns into a clinically significant condition,” write Somer and Nirit Soffer-Dudek at Ben-Gurion University of the Negev, in a new paper on the disorder, published in Frontiers in Psychiatry.
This is Episode 11 of PsychCrunch the podcast from the British Psychological Society’s Research Digest, sponsored by Routledge Psychology. Download here.
Can psychology help us get a better night’s sleep? Our presenter Ginny Smith hears how worry about sleep is sometimes more of a problem than lack of sleep itself. She gives us some evidence-backed sleep tips and finds out about “sleep engineering” – deliberately manipulating the sleep process to aid memory and enhance its health benefits.
You’ve had all day to worry, but your brain decides that the moment you rest your weary head upon your pillow is the precise instant it wants to start fretting. The result of course is that you feel wide awake and cannot sleep. Two possible solutions: (1) spend five minutes before lights out writing about everything you have done. This might give you a soothing sense of achievement. Or (2) spend five minutes writing a comprehensive to-do list. This could serve to off-load your worries, or perhaps it will only make them more salient? To find out which is the better strategy, a team led by Michael Scullin at Baylor University invited 57 volunteers to their sleep lab and had half of them try technique 1 and half try technique 2. Their findings are published in the latest issue of the Journal of Experimental Psychology: General.
“In the dark, in the quiet, in the lonely stillness, the aggrieved struggle to rescue sleep from vigilance.” This arresting sentence introduces a new review of insomnia in Behaviour Research and Therapy that addresses a troubling fact observed in sleep labs across the world: poor sleep is not sufficient to make people consider themselves to have the condition… and poor sleep may not even be necessary. The paper, by Kenneth Lichstein at the University of Alabama, explores the implications of “Insomnia Identity”: how it contributes to health problems, and may be an obstacle to recovery.
For me, dreams and creativity have always been wound tightly together. As a teenager leafing through my dad’s Heavy Metal comic strip anthologies, it was Little Nemo in Slumberland (about a character who has fantastic dreams) that stunned me the most. When I became a psychology researcher, I was fascinated with altered states and formed a short-lived dream research group with my fellow PhD students – somnambulant life seemed so mysterious, and the then-received wisdom that dreams were just brain static was becoming untenable. Today, outside of my science hours, I perform improvisational theatre, most intensively with The Dreaming, a surrealistic troupe mimicking dream-logic. And in recent years, I’ve made my sporadic dream-logging into a habit (tip: keep a voice recorder by your bed and capture everything you can without worrying about sense or structure). Could this habit make me more creative? According to new research published in the Journal of Creative Behavior, it could.
Cognitive performance fluctuates throughout the day. Depending on their “chronotype” some people are sharpest in the morning (“larks”), while others generally prefer the later hours of the day (“owls”). For obvious reasons, this is mirrored in our preferred sleep routines: larks get tired in the evenings earlier and, as a consequence, also wake up earlier, while owls show the opposite pattern. Your chronotype is not something that you’re stuck with for the rest of your life, but it changes with age. In fact we’re most likely to show an owl-like chronotype during adolescence, which might at least partly explain why teenagers often stay up late and arrive at school with eyes bloodshot thanks to a hefty sleep debt.
But if late chronotypes are so common in adolescents, why does school start so early (usually well before 9am in the UK, Netherlands and Germany)? Doesn’t that mean that many students are likely to be constantly sleep-deprived and not assessed during their biological peaks? Yes, it does! In fact, there is a lot of evidence to suggest that school kids who have a late chronotype score lower grades. But besides reduced sleep time, there are several alternative explanations for why a late chronotype could be associated with lower academic performance (such as absenteeism, for instance) as explored in a new paper in Scientific Reports. The researchers, led by Giulia Zerbini at University of Groningen, say their findings might help us understand the chronotype/school grade link and how we can fix it.