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Explained: How memories are 'pruned' during sleep
The pair of papers suggest that sleep is crucial in order to wipe out memories. Yep – it turns out that, sometimes, it's smart to forget.
Why do we sleep? We know what happens when we don't get enough. But what is its evolutionary purpose – what kind of changes do our brains undergo when we sleep? A pair of papers published in the journal Science in 2017 have evidence to suggest our brains undergo a pruning cycle while we rest.
Its important to note these studies are still in their early stages. The tests were done on mice.
The results of the study suggest sleep may allow our synapses to undergo a maintenance period. Synapses are the gaps between neurons, across which information is transmitted, and they are a critical part of memory formation. The studies posit that the sleep process trims the fat and adds clarity to our memories, letting us forget the less relevant information while strengthening memories that may be important. When blocking the chemical responsible for trimming the synapses during sleep, the researchers found those mice's memories became fuzzy.
However, its uncertain whether this is a function of sleep, or if sleep is the function. These tests were done in a lab setting, controlled and optimized. However, modern humans don't abide by a natural sleep cycle anymore – we look at our phones before bed and expose ourselves to things that cause our brains to think sleep is not on the menu. Some believe this has caused a spike in sleep aids.
The Atlantic reported back in 2014 that the use of sleeping pills has been on the rise:
"The number of prescriptions for nonbenzodiazepine sedative hypnotics, a group of drugs to which zolpidem belongs, grew 30 times over between 1994 and 2007—that's five times faster than the growth of insomnia diagnoses over the same period of time, and 21 times faster than the growth of patient complaints of sleeplessness. Somewhere between 50 and 70 million Americans are currently thought to suffer from sleep disorders, according to the Centers for Disease Control and Prevention, and around 4 percent of adults use prescription medication to get a good night's rest."
Joshua Liao, a physician at Brigham and Women's Hospital in Boston and a clinical fellow at Harvard Medical School, says much of the issues relating to insomnia can be dealt with by practicing good sleep hygiene. If people avoided napping, eating or drinking caffeine or alcohol, and looking at their phone right before bed, they might not require a chemical crutch to get some rest.
The evidence for sleeping pills giving people restorative sleep relies mostly on self-observation.
“Do you feel more rested, more alert, more able to concentrate, less irritable on medication versus off?" Dr. Daniel J. Buysse told the New York Times. "If all those things are true then I would say it's more restorative. If a hypnotic drug leaves you feeling hung over or more anxious, if it causes you to order five hickory smoked turkeys on the Internet without remembering, then it's probably not good."
But the larger question of what happens to our brains in the longterm is still unknown. The abundance of light and our "natural" bedtime habits have changed considerably in these modern times. What we do know is the practice of good pre-bedtime habits might help you get a good night's rest and, if the study above proves true for humans, form clearer memories.
The New York Times has more on this study.
Welcome to the world's newest motorsport: manned multicopter races that exceed speeds of 100 mph.
- Airspeeder is a company that aims to put on high-speed races featuring electric flying vehicles.
- The so-called Speeders are able to fly at speeds of up to 120 mph.
- The motorsport aims to help advance the electric vertical take-off and landing (eVTOL) sector, which could usher in the age of air taxis.
Airspeeder, the world's newest motorsport, is set to debut its first race in 2021.
What can you expect to see? Something like a mix between Red Bull's air racing and the pod-racing scenes from "Star Wars: The Phantom Menace" — manned electric cars flying close together in the desert at 120 mph, nose-diving off cliffs, and racing over lakes, all while hopefully avoiding collisions.
Airspeeder calls its vehicles flying electric cars, but it's probably easier to think of the wheelless multicopters as car-sized drones. Powered by electric batteries, the carbon-fiber craft use eight propellers to fly, and the tiltable motors are designed to allow pilots to navigate through the course's pylons at high speeds.
To prevent crashes, Airspeeder is working with the companies Acronis and Teknov8 to develop "high-speed collision avoidance" systems for its Speeders.
"As they compete, Speeders will utilise cutting-edge LiDAR and Machine Vision technology to ensure close but safe racing, with defined and digitally governed no-fly areas surrounding spectators and officials," Airspeeder wrote in a blog post.
Beyond motorsports, Airspeeder hopes to help advance the electric vertical take-off and landing (eVTOL) sector. This sector is where companies like Uber, Hyundai, and Airbus are working to develop air taxis, which could someday take the ridesharing industry into the skies. By 2040, the autonomous urban aircraft industry could be worth $1.5 trillion, according to a 2019 report from Morgan Stanley.
Still, many technical and regulatory hurdles remain. Matt Pearson, Airspeeder's founder and CEO, thinks the futuristic motorsport will help to not only speed up that process, but also pave the way for self-driving cars.
"Even with autonomous vehicles on the ground, it's a difficult thing to get right because computers have to make decisions very fast," Airspeeder's founder and CEO, Matt Pearson, told GQ." But in a racing environment, you have a pretty controlled course and you have the ability to make all the vehicles cooperate with each other. You have a whole load of vehicles talking to each other, so if there's an incident or a pilot slows down or there's a traffic jam on the course they're all aware of each other. This is something we think will revolutionise autonomous vehicles on the ground. It's technology that will make flying cars a reality in our cities in the future."
Airspeeder has yet to announce a date for the first race, but Pearson said he hopes to put on three races over the first season. The company is developing two courses: one in California's Mojave Desert, and one near Coober Pedy in South Australia.
The way you speak might reveal a lot about you, such as your willingness to engage in casual sex.
- A new study finds a deeper voice is associated with self-reported extraversion, dominance, and casual sex.
- It was the first study on the topic to objectively measure voice pitch.
- The authors suggest that hormones like testosterone might explain their findings.
We make snap decisions about other people based on information that we can gather quickly. One of the many ways that we do this is by making bold conclusions about other people's personalities based on their voices alone. Various studies demonstrate that people associate a deep voice with dominance, but those with higher pitched voices are perceived as nervous or neurotic. Popular culture seems to agree with and reinforce these stereotypes.
Are these perceptions accurate? Maybe. A new study by an international team of researchers with the goal of more accurately determining what our voices reveal about us has demonstrated that there is some connection between how we sound and who we think we are.
The voice-personality connection
Lead author Dr. Julia Stern of the University of Göttingen explained:
"Even if we just hear someone's voice without any visual clues — for instance on the phone — we know pretty soon whether we're talking to a man, a woman, a child, or an older person. We can pick up on whether the person sounds interested, friendly, sad, nervous, or whether they have an attractive voice. We also start to make assumptions about trust and dominance. The first step was to investigate whether voices are, indeed, related to people's personality."
The study included data from 2,000 people from four countries involved in eleven previous independent studies focused on other questions. Each of these studies involved some kind of self-reporting of personality traits and vocal recordings. The recordings were analyzed with Praat, software that determined the frequencies of the participants' speaking voices.
The study is the largest ever conducted on the topic and the first to use an objective measure of pitch rather than subjective rankings such as "high pitched" or "deep." Each participant's vocal pitch was then compared to the self-reported personality data they provided.
The findings associated self-reported levels of dominant tendencies, extroversion, and increased interest in and acceptance of sociosexuality (casual sex or sex outside of a relationship) with a lower pitched voice. This was true for men and women of any age. The findings were in line with the previous, less robust studies on the subject.
Other stereotypes, like if a higher pitched voice hints at neuroticism, openness to new experiences, or agreeableness, were impossible to determine with the data at hand.
Voice isn't everything
It should be remembered that the personality traits that this study associates with vocal pitch are self-reported, so there are some serious limitations. For instance, it is entirely possible that vocal pitch is associated with thinking you're extroverted when you actually aren't. Furthermore, all four countries in the study are WEIRD, so the findings probably cannot be universalized.
Additionally, there are plenty of examples of people for whom the voice-personality link doesn't apply. For example, Teddy Roosevelt, an extremely extroverted, dominating man, had a fairly high pitched voice.
The authors do speculate that there could be a connection between testosterone levels in men, their vocal pitch, and their perceived level of dominance that would be supported by previous studies. However, they have no hypothesis explaining why that same relationship exists for women.
The authors suggest that further studies in this area could focus on finding a possible physical connection between these traits and vocal pitch and to determine if they hold for traits which are not self-reported.
Who needs steroids when you have the placebo effect?
- A study suggests that the effectiveness of sports drinks may depend in part on their color.
- Runners who rinsed with a pink liquid ran better than those who consumed the same but colorless drink.
- Improvement in their performance is likely due to a placebo effect.
The "placebo effect" is real. It's the name for a strange phenomenon that most notably occurs during clinical trials. People who are given an inactive substance, like a sugar pill, often experience the same therapeutic benefit as those who are given actual medicine. It's not their imagination — it really happens. (Even better, recent research suggests that therapeutic benefits occur even when the person knows that they were given a placebo.)
Now, a new study from the University of Westminster (UOW) Centre for Nutraceuticals in London and published in Frontiers in Nutrition suggests that the placebo effect may explain yet another phenomenon: Athletic performance.
The research showed that treadmill runners who rinsed their mouths with a pink liquid increased their performance over runners who swished with exactly the same liquid but without the coloring. Why pink? The color is generally linked to sweetness, and the researchers wondered if that association would subconsciously trick the runners into an expectation of more carbohydrates and thus energy.
Author Sanjoy Deb explains:
"The influence of color on athletic performance has received interest previously, from its effect on a sportsperson's kit to its impact on testosterone and muscular power. Similarly, the role of color in gastronomy has received widespread interest, with research published on how visual cues or color can affect subsequent flavor perception when eating and drinking."
Running for science
Credit: Ryan De Hamer / Unsplash
For the study, the researchers recruited ten healthy adults — six men, four women. All were regular exercisers, with an average age of 30. The participants were told that they would be testing the relative benefits of two commercial sports drinks after watching a brief video explaining the value of such beverages. Previous research found that mid-exercise rinsing with such drinks can reduce the perceived intensity of exercise.
The drinks consisted of 0.12 grams of sucralose dissolved in 500 mL of plain water — an artificially sweetened rinse low in calories. The liquids contained no other additives common to sports drinks such as caffeine. The pink version had non-caloric coloring added but was otherwise identical.
After a 12-minute warmup phase of jogging followed by running, the athletes ran at a difficult pace for 30 minutes, rinsing with their drinks as they ran. Following a brief cool-down, they were interviewed to capture their impressions of the exercise session. (Each runner tested both drinks.)
The researchers found that when the volunteers used the pink rinse, they ran an average of 212 meters farther and 4.4 percent faster. They also enjoyed the exercise more.
Deb said, "The findings from our study combine the art of gastronomy with performance nutrition, as adding a pink colorant to an artificially sweetened solution not only enhanced the perception of sweetness, but also enhanced feelings of pleasure, self-selected running speed, and distance covered during a run."
The researchers also plan to dig deeper into the phenomenon by investigating the possibility that the pinkness of the beverage is somehow directly activating the brain's reward areas.