6 Factors That Determine Whether or Not You Remember Your Dreams

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Within the scientific community, dreams are still something of a mystery. Many experiments have been conducted and many theories have been put forth, but researchers still don’t fully understand why or how we dream. Further complicating matters is the fact that everyone dreams, but some people never remember their subconscious escapades.

However, improvements in brain imaging and recent physiological studies have brought us one step closer to answering the question of why some people remember their dreams more than others. There’s no simple, definitive explanation, “but there are a number of things that correlate,” Dr. Deirdre Leigh Barrett, a psychology professor at Harvard Medical School and author of The Committee of Sleep, tells Mental Floss. Barrett shared a few of the factors that can affect your dream recall.

1. SEX

Women, on average, recall more dreams than men. Researchers aren’t exactly sure why, but Barrett says it could be a biological or hormonal difference. Alternatively, women might be more cognizant of their dreams because they tend to be more interested in dreams in general. However, Barrett notes that differences between men and women in regard to dream recall are “modest” and that there are greater differences within each sex than between the sexes. In other words: There are plenty of women with low dream recall and plenty of men with high dream recall.

2. AGE

As we get older, it often gets harder to recall our dreams. Your ability to remember dreams improves in late childhood and adolescence, and tends to peak in your twenties, Barrett says. After that point, people often experience a gradual drop-off in dream recall. However, there are exceptions, and people sometimes experience the opposite.

3. PERSONALITY

Again, this is by no means a prescriptive rule, but there seems to be a correlation between certain personality traits and high dream recall. "More psychologically-minded people tend to have higher dream recall, and people who are more practical and externally focused tend to have lower recall," Barrett says. In addition, better dream recall has a “mild correlation” with better recall while completing certain memory tasks during waking hours, according to Barrett.

4. AMOUNT OF SLEEP

The amount of sleep one gets on average is one of the most important factors related to dream recall. People dream every 90 minutes during the REM (rapid eye movement) sleep cycle. However, those REM periods get longer throughout the night, meaning that you’re doing the most dreaming toward the morning—generally right before you wake up. If you only sleep four hours instead of eight, you’re only getting about 20 percent of your dream time. For this reason, some people report remembering more of their dreams on the weekend, when they have the chance to catch up on sleep.

5. BRAIN ACTIVITY

Thanks to brain imaging, scientists now have a better idea of which parts of the brain are associated with dreaming. A part of the brain that processes information and emotions is more active in people who remember their dreams more often, according to a 2014 study. This region toward the back of the brain, called the temporo-parietal junction (TPJ), may help people pay more attention to external stimuli. In turn, this may promote something called instrasleep wakefulness.

"This may explain why high dream recallers are more reactive to environmental stimuli, awaken more during sleep, and thus better encode dreams in memory than low dream recallers," Dr. Perrine Ruby told the International Business Times. "Indeed, the sleeping brain is not capable of memorizing new information; it needs to awaken to be able to do that."

Higher activity in the TPJ and another region of the brain called the medial prefrontal cortex (MPFC) might also "promote the mental imagery and/or memory encoding of dreams," researchers wrote in the study's abstract.

More recently, in 2017, researchers discovered that high dream recall is also linked to higher activity toward the front of the brain. The pre-frontal cortex is the part of the brain that deals with abstract thinking, so it makes sense that it has been linked to dream recall and lucid dreaming (being aware that one is dreaming), Barrett says.

6. RESPONSE TO EXTERNAL STIMULI

In a similar vein, people who remember their dreams more frequently also tend to exhibit more brain activity after hearing their name spoken aloud while they’re awake, according to a 2013 study. Upon hearing their names, a group of “high recallers,” who remember their dreams almost every night, experienced a greater decrease in a brain wave called the alpha wave than a group of “low recallers,” who remember their dreams once or twice a month. This decrease in alpha waves is likely preceded by an increase in brain activity upon hearing their names. Essentially, people with greater dream recall tend to experience activity in more regions of their brain in response to sounds. According to Barrett, there may be an evolutionary explanation for this.

“Evolution wants us to get restorative sleep but it also wanted us to wake up to danger and check it out and be able to go back to sleep quickly afterwards,” she says. Think of the all the dangers our prehistoric ancestors had to deal with, and it's clear that this response is important for survival. In essence, high recallers are “probably just a little more aware and watching during their dream, and that helps make it a long-term memory.”

So what can you do to help you remember your dreams? It may sound simple, but before you go to bed, think to yourself, “I’m going to remember my dreams tonight.” The very act of thinking about dreaming can make a big difference.

“You could say that just reading this article is somewhat more likely to make you recall a dream tonight,” Barrett says. “People who are taking a class on dreams or reading a book on dreams—any short-term intervention of paying more attention to them—tends to create a short-term blip in dream recall.”

When you first wake up, don’t do anything except lie in bed and try to recall any dreams you had. If something comes back to you, write it down or use a voice recorder to crystallize your thoughts. Dreams are still in your short-term memory when you wake up, so they’re fragile and easy to forget.

If you don’t remember anything, Barrett says it’s still helpful to assess how you feel when you first awaken. Are you happy, sad, or anxious? “Sometimes if you just stay with whatever emotion or little bit of content you woke up with,” she says, “a dream will come rushing back.”

A Simple Skin Swab Could Soon Identify People at Risk for Parkinson's

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iStock.com/stevanovicigor

More than 200 years have passed since physician James Parkinson first identified the degenerative neurological disorder that bears his name. Over five million people worldwide suffer from Parkinson’s disease, a neurological condition characterized by muscle tremors and other symptoms. Diagnosis is based on those symptoms rather than blood tests, brain imaging, or any other laboratory evidence.

Now, science may be close to a simple and non-invasive method for diagnosing the disease based on a waxy substance called sebum, which people secrete through their skin. And it’s thanks to a woman with the unique ability to sniff out differences in the sebum of those with Parkinson's—years before a diagnosis can be made.

The Guardian describes how researchers at the University of Manchester partnered with a nurse named Joy Milne, a "super smeller" who can detect a unique odor emanating from Parkinson's patients that is unnoticeable to most people. Working with Tilo Kunath, a neurobiologist at Edinburgh University, Milne and the researchers pinpointed the strongest odor coming from the patients' upper backs, where sebum-emitting pores are concentrated.

For a new study in the journal ACS Central Science, the researchers analyzed skin swabs from 64 Parkinson's and non-Parkinson's subjects and found that three substances—eicosane, hippuric acid, and octadecanal—were present in higher concentrations in the Parkinson’s patients. One substance, perillic aldehyde, was lower. Milne confirmed that these swabs bore the distinct, musky odor associated with Parkinson’s patients.

Researchers also found no difference between patients who took drugs to control symptoms and those who did not, meaning that drug metabolites had no influence on the odor or compounds.

The next step will be to swab a a much larger cohort of Parkinson’s patients and healthy volunteers to see if the results are consistent and reliable. If these compounds are able to accurately identify Parkinson’s, researchers are optimistic that it could lead to earlier diagnosis and more effective interventions.

[h/t The Guardian]

World’s Oldest Stored Sperm Has Produced Some Healthy Baby Sheep

A stock photo of a lamb
A stock photo of a lamb
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It’s not every day that you stumble across a 50-year-old batch of frozen sheep sperm. So when Australian researchers rediscovered a wriggly little time capsule that had been left behind by an earlier researcher, they did the obvious: they tried to create some lambs. As Smithsonian reports, they pulled it off, too.

The semen, which came from several prize rams, had been frozen in 1968 by Dr. Steve Salamon, a sheep researcher from the University of Sydney. After bringing the sample out of storage, researchers thawed it out and conducted a few lab tests. They determined that its viability and DNA integrity were still intact, so they decided to put it to the ultimate test: Would it get a sheep pregnant? The sperm was artificially inseminated into 56 Merino ewes, and lo and behold, 34 of them became pregnant and gave birth to healthy lambs.

Of course, this experiment wasn’t just for fun. They wanted to test whether decades-old sperm—frozen in liquid nitrogen at -320°F—would still be viable for breeding purposes. Remarkably, the older sperm had a slightly higher pregnancy rate (61 percent) than sheep sperm that had been frozen for 12 months and used to impregnate ewes in a different experiment (in that case, the success rate was 59 percent).

“We believe this is the oldest viable stored semen of any species in the world and definitely the oldest sperm used to produce offspring,” researcher Dr. Jessica Rickard said in a statement.

Researchers say this experiment also lets them assess the genetic progress of selective breeding over the last five decades. “In that time, we’ve been trying to make better, more productive sheep [for the wool industry],” associate professor Simon de Graaf said. “This gives us a resource to benchmark and compare.”

[h/t Smithsonian]

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