You are getting sleepy, very sleepy. When your head hits the pillow it’s lights out for the brain and body, right? Not if you consider the brain cells that must fire to produce the sometimes vivid and sometimes downright haunted dreams that take place during the rapid-eye-movement stage of your sleep. Why do some people have nightmares while others really spend their nights in bliss? Like sleep, dreams are mysterious phenomena. But as scientists are able to probe deeper into our minds, they are finding some of those answers. Here's some of what we know about what goes on in dream land.
Dreams are meaningful
If you dream about winning the lottery or having an accident, should you prepare? If you answered "yes," you’re not alone, according to a study published in the February 2009 issue of the Journal of Personality and Social Psychology. The researchers ran six experiments, finding that not only do we put stock in our dreams, we also judge dreams that fit with our own beliefs as more meaningful than ones that go against the grain.
"Psychologists' interpretations of the meaning of dreams vary widely," study researcher Carey Morewedge, an assistant professor at Carnegie Mellon University, said in a statement. "But our research shows that people believe their dreams provide meaningful insight into themselves and their world."
In one study, 182 commuters in Boston imagined one of four scenarios had happened the night before a scheduled trip: national threat level was raised to orange; they consciously thought about their plane crashing; they dreamed about a plane crash; or a real plane crash occurred on the route they planned to take. Results showed a plane-crash dream was more likely to affect travel plans than either thinking about a crash or a government warning, while the crash dream also produced a similar level of anxiety as did an actual crash.
In another study, 270 men and women completed an online survey in which they were asked to remember a past dream they had about a person they knew. People ascribed more importance to pleasant dreams about a person they liked than they did a person they didn't like. And they were more likely to report a negative dream as more meaningful if it was about a person they disliked than one about a friend.
Violent dreams can be warning sign
As if nightmares weren't bad enough, a rare sleep disorder causes people to act out their dreams, sometimes with violent thrashes, kicks and screams. Such violent dreams may be an early sign of brain disorders down the line, including Parkinson's disease and dementia, according to research published online July 28, 2010, in the journal Neurology. The results suggest the incipient stages of these neurodegenerative disorders might begin decades before a person, or doctor, knows it. [Read full story]
Night owls have more nightmares
Staying up late has its perks (as long as you can hit the snooze button the next morning), but light dreams is not one of them. Research published in 2011 in the journal Sleep and Biological Rhythms, revealed that night owls are more likely than their early-bird counterparts to experience nightmares.
In the study 264 university students rated how often they experienced nightmares on a scale from "0," (meaning "never") to "4" (meaning "always"). The stay-up-late types scored, on average, a 2.10, compared with the morning types who averaged a 1.23. The researchers said the difference was a significant one, however, they aren’t sure what's causing a link between sleep habits and nightmares. Among their ideas is the stress hormone cortisol, which peaks in the morning right before we wake up, a time when people are more prone to be in REM, or dream, sleep. If you’re still sleeping at that time, the cortisol rise could trigger vivid dreams or nightmares, the researchers speculate. [Read full story]
Dreams help us solve puzzles
Scientists have long wondered why we dream, with answers ranging from Sigmund Freud's idea that dreams fulfill our wishes to the speculation that these wistful journeys are just a side rapid-eye-movement, or REM, sleep. Turns out, at least part of the reason may be critical thinking, according to Harvard psychologist Deirdre Barrett who presented her theory in 2010 at the Association for Psychological Science meeting in Boston. She has found that our slumbering hours may help us solve puzzles that have plagued us during daylight hours.
According to Barrett, it's the visual and often illogical aspects of dreams that make them perfect for out-of-the-box thinking that is necessary to solve some problems.
"Whatever the state we're put in, we're still working on the same problems," Barrett said, adding that while dreams may have original evolved for another purpose, they have likely been refined over time for multiple tasks, including helping the brain reboot and helping us solve problems. [Read full story]
Men dream about sex
No surprise here, men are more likely than women to dream about sex. And comparing notes in the morning may not be a turn on for either guys or gals, as women are more likely to have experienced nightmares, according to doctoral research reported in 2009 by psychologist Jennie Parker of the University of the West of England.
In her study of nearly 200 men and women, ages 18 to 25, Parker found that women's nightmares could be broadly divided into three categories: fearful dreams (being chased or life threatened), dreams involving the loss of a loved one, or confused dreams.
"If women are asked to report the most significant dream they ever had, they are more likely than men to report a very disturbing nightmare," Parker said. "Women reported more nightmares, and their nightmares were more emotionally intense than men's." [Read full story]
This doesn't mean women have no fun in their dreams. A study presented in 2007 at a meeting of the Associated Professional Sleep Societies (APSS) revealed that of about 3,500 home dream reports about 8 percent contain some form of sexual-related activity. The most common sexual dream involved sexual intercourse, followed by sexual propositions, kissing, fantasies and masturbation.
You can control your dreams
If you're interested in lucid dreaming, you may want to take up video gaming. Both represent alternate realities, according to Jayne Gackenbach, a psychologist at Grant MacEwan University in Canada. Of course they aren't completely the same. While video games are controlled by computers and gaming consoles, dreams arise from the human mind.
"If you're spending hours a day in a virtual reality, if nothing else it's practice," Gackenbach told LiveScience in 2010. "Gamers are used to controlling their game environments, so that can translate into dreams." Her past research has shown that people who frequently play video games are more likely than non-gamers to have lucid dreams where they view themselves from outside their bodies; they also were better able to influence their dream worlds, as if controlling a video-game character.
That level of control may also help gamers turn a bloodcurdling nightmare into a carefree dream, she found in a 2008 study. This bar of sorts against nightmares could help war veterans suffering from post-traumatic stress disorder (PTSD) after combat, Gackenbach reasons. [Read full story]
Dreams can take the edge off
Taking the edge off may require, not a stiff drink, but a trip to la-la land. UC Berkeley scientists report in the Nov. 23, 2011, issue of the journal Current Biology that during the dream phase of sleep (also called REM sleep), participants' brains showed decreased levels of certain chemicals associated with stress.
"We know that during REM sleep there is a sharp decrease in levels of norepinephrine, a brain chemical associated with stress," study researcher Matthew Walker, associate professor of psychology and neuroscience, said in a statement. "By reprocessing previous emotional experiences in this neuro-chemically safe environment of low norepinephrine during REM sleep, we wake up the next day, and those experiences have been softened in their emotional strength. We feel better about them, we feel we can cope."
The findings, Walker and colleagues say, may explain why people with post-traumatic stress disorder (PTSD), such as war veterans, have such a tough time recovering from painful experiences and suffer reoccurring nightmares. They also provide at least one explanation for why we dream. [Read full story]
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Jeanna served as editor-in-chief of Live Science. Previously, she was an assistant editor at Scholastic's Science World magazine. Jeanna has an English degree from Salisbury University, a master's degree in biogeochemistry and environmental sciences from the University of Maryland, and a graduate science journalism degree from New York University. She has worked as a biologist in Florida, where she monitored wetlands and did field surveys for endangered species. She also received an ocean sciences journalism fellowship from Woods Hole Oceanographic Institution.