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5 Scientific Facts About Your Dreams

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Throughout human history, dreams have been the subject of science and pseudoscience alike. In today’s crazy online world where you can’t always believe your eyes, we hope you’ll sleep better knowing that the following facts are the real deal.

1. Dream logic is neurologically logical

Your brain’s activity looks very different when you’re asleep, which sheds some light on the nature of dreams. For starters, your primary visual cortex is out of commission during sleep (because your eyes are closed), but your secondary visual cortex (which normally interprets outside visual stimuli) is still going at it, trying to make sense of the images the rest of your brain is conjuring up.

Your limbic system (hippocampus and fornix––the wormy tangle all up in the middle of your brain) is the primary control center for your emotions, and it becomes especially active during your dreams. This explains why dreams are so emotionally charged, and often deal with feelings of imminent danger. Meanwhile, the dorsolateral prefrontal cortex, which controls logic and rationality, is practically dormant, which explains why you can dream yourself marrying Hugh Griffith in an cosmonaut suit and be like, “Can we have the guests throw sand instead of Cracker Jacks, Hughie? Birds tend to choke on the prizes.”

2. You also dream during “non-REM” sleep

By now everyone knows that we categorize human sleep in five stages: some deep stages with boring number-names, and REM, famously responsible for dream time. Au contraire! More recent research indicates that dreaming also occurs during non-REM sleep (slyly abbreviated as NREM). REM sleep is the stage closest to waking, though, so you’re more likely to remember REM dreams than those in NREM.

Since each sleep stage represents different brain activity, different stages will result in different types of dreams. During REM sleep, for instance, people typically report interacting with two to three characters outside of themselves––usually people they know in waking life––while NREM may host more characters, more of whom are strangers. At the same time, the dreamer more often initiates socially aggressive interactions in REM sleep, while NREM hosts friendlier social initiations. Makes it hard not to read a “don’t you dare wake me up” subtext into those REM dreams... 

3. Pain Can Show Up in Dreams

While it’s never been proven that dreams themselves can produce pain, a few studies have suggested that real-world pain can incorporate into dreams. In one study, a lab-induced “pins and needles” sensation manifested as a problematic shoe-fitting in the subject’s dream, while more intense pain (like that experienced by healing burn victims in a 2002 study) can produce nightmares wherein the dreamer tries to escape the source of their pain, literally and metaphorically. In short, pain transcends the barrier between waking and dreaming life, and shows up in our dreams relatively untransformed. 

4. Dreams Help You Learn

You’ve heard the term “Let me sleep on it,” from Meat Loaf and others, and it’s a good idea, scientifically speaking. That’s because your brain can teach itself while you sleep, thanks to a process Harvard neuroscience professor Robert Stickgold calls off-line memory reprocessing.

In his series of experiments, Stickgold had subjects perform simple tasks like recognizing words or hitting a digital target, and compared their progress with their sleep patterns. The logic is this: Any time you make a memory, that new information has to transfer between several different parts of your brain in order to stick around for awhile, and those same patterns correspond with the patterns of brain activity during sleep. Sure enough, subjects who slept on their lessons showed greater improvement. In his Tetris experiment, Stickgold’s subjects even reported dreaming about Tetris as the learning period went on, indicating a connection between the need to improve, dreams, and post-dream improvement.

5. Dreams do Affect Your Mood

You probably already knew this: The tone of a dream can set the tone of the following morning, for better or worse. But there’s more to it than that. “Daytime mood and social interactions” have been found to correlate with dream details––although universal patterns across dreams are almost impossible to quantify reliably. Details as seemingly arbitrary as the number of characters the dreamer encounters may have more to do with the person’s actual sleep patterns than actual dream content (see bullet #2). But as in Stickgold’s memory experiments, dreaming about stuff that’s bothering you can help the brain process during sleep what you might not be thrilled to process during the day (see bullet #5). In short: Dream on, little dreamer. It’s good for ya.

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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Here's How to Change Your Name on Facebook
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Whether you want to change your legal name, adopt a new nickname, or simply reinvent your online persona, it's helpful to know the process of resetting your name on Facebook. The social media site isn't a fan of fake accounts, and as a result changing your name is a little more complicated than updating your profile picture or relationship status. Luckily, Daily Dot laid out the steps.

Start by going to the blue bar at the top of the page in desktop view and clicking the down arrow to the far right. From here, go to Settings. This should take you to the General Account Settings page. Find your name as it appears on your profile and click the Edit link to the right of it. Now, you can input your preferred first and last name, and if you’d like, your middle name.

The steps are similar in Facebook mobile. To find Settings, tap the More option in the bottom right corner. Go to Account Settings, then General, then hit your name to change it.

Whatever you type should adhere to Facebook's guidelines, which prohibit symbols, numbers, unusual capitalization, and honorifics like Mr., Ms., and Dr. Before landing on a name, make sure you’re ready to commit to it: Facebook won’t let you update it again for 60 days. If you aren’t happy with these restrictions, adding a secondary name or a name pronunciation might better suit your needs. You can do this by going to the Details About You heading under the About page of your profile.

[h/t Daily Dot]

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