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  • We get asked a lot of questions here at SciShow.

  • Sometime we get a question that has maybe never been asked before in the history of

  • questions, and sometimes we get questions that are so universally wondered, that they

  • get asked over and over again.

  • So, we've compiled some of those frequent asks into one place, here, so hopefully, if

  • you've ever wondered these curious questions, you can get a whole bunch of answers right

  • now.

  • Recently, Patreon patron, Rob Margolis, reminded us of two of these questions that come up

  • a lot.

  • The first, I hope you're not wondering right now, but if you are, I hope you recover quickly

  • and can watch this video about what causes migraines.

  • If you've never had a migraine, you might think it's just a really bad headache.

  • But if you've ever had them, or you know someone who does, you know that they're

  • much worse -- and much more complicated -- than that.

  • A true migraine is a multi-symptom disorder of the central nervous system that affects

  • the brain.

  • But, yes, really bad headaches are a major component of it -- probably the single most

  • significant and identifiable component.

  • But it usually lasts longer than a normal headache -- anywhere from 4 hours to several

  • days// -- and brings a whole array of other symptoms with it.

  • Most migraine sufferers experience extreme sensitivity to light and sound, and sometimes

  • smells.

  • They also commonly experience nausea, vomiting, even fainting.

  • What little relief they can find is generally only achieved by being very still in a dark,

  • silent room until the symptoms pass.

  • And believe it or not, it gets worse.

  • Migraines also cause problems both before and after the headache.

  • It's different for everyone, but the ordeal can start with symptoms as seemingly minor

  • as constipation, weird food cravings, neck stiffness, or excessive yawning.

  • As the symptoms worsen, people generally enter a phase called aura, in which they may experience

  • things like vision disturbances -- like seeing shapes or lights, blurred or doubled vision,

  • or even loss of vision -- “pins and needlessensations in the extremities, weakness, and

  • sometimes even slurred speech.

  • Now, you might notice that these sound a lot like the symptoms of a stroke, and in fact

  • migraines have so many things in common with strokes that doctors sometimes have to do

  • tests to determine which disorder they're dealing with.

  • After the headache has passed, most migraine sufferers experience a period of weakness

  • and fatigue that can last from a few hours to a few days.

  • Obviously this isn't the sort of thing that anyone wants to experience.

  • So what causes it?

  • Can it be controlled?

  • Or at least treated?

  • Doctors think migraines are probably caused by a sharp drop in your brain's levels of

  • serotonin -- a neurotransmitter that plays a key role in regulating things like sleep

  • and mood.

  • And once that imbalance strikes, it causes a whole cascade of effects.

  • But what triggers this imbalance is complicated and uncertain.

  • We do know that one of the most important factors is genetics.

  • If one or both of your parents has experienced a migraine, odds are that you will too.

  • For reasons that we don't understand, women are far more likely to have migraines than

  • men, and they're even more likely to experience one during times of hormonal changes, like

  • puberty, menstruation, ovulation, pregnancy, when using hormonal contraceptives or hormone

  • replacements, and menopause.

  • Beyond that, everyone's triggers are different.

  • For many people, it may depend on stress, their activity level or their sleep schedule

  • -- all things in which serotonin plays a role.

  • And still others may be triggered by things as seemingly random as bright lights, loud

  • sounds, unusual or strong smells, or even weather changes.

  • The //treatment// of migraines is further evidence that it's not just a headache.

  • It's true that the headache itself can sometimes be treated with pain relievers, although they're

  • often less effective.

  • In addition to pain relief, migraine sufferers may take medications that try to treat the

  • source of attacks, like by controlling the constriction of blood vessels in the brain,

  • blood pressure, serotonin levels, and inflammation.

  • So clearly a migraine is more than just a bad headache, remember that when you hang

  • out with people who get them.

  • If they're in a bad way, the biggest favor you can give them is just to let them be by

  • themselves in a dark room.

  • You can just keep watching SciShow //quietly//.

  • Rob's second question is another that comes up a lot, but is less painful...for humans

  • anyway.

  • Welcome to I Don't Think It Means What You Think It Means, where we look at bits of scientific

  • theory that've wiggled their way into popular culture and taken on a life of their own.

  • Today we're talking about Schrodinger's Cat, a famous thought experiment devised by

  • Austrian physicist Erwin Schrodinger, who helped piece physics back together after Einstein

  • and his crew blew a giant honkin' hole in it back in the early 20th century.

  • It can't really be overstated how much of a giant crap circus the 1920's were for

  • physicists.

  • Until then, everything had pretty much just been good old-fashioned Newtonian physics

  • -- where you could observe objects moving, and predict how they'd react to various

  • forces.

  • But then along came new research into subatomic particles that showed they didn't act predictably

  • at all.

  • In fact, sometimes stuff seemed to be two things at once.

  • Like, an electron in a beam might act like a particle sometimes and like a wave at other

  • times.

  • And to make things even more -- [heaves tense sigh, sort of like hyperventilating]-- the

  • more you try to observe and measure these particles, the less naturally they seem to

  • behave.

  • Sphincter-say-what, now?

  • [js: Um, it's from Wayne's World and I think I'm trying to bring it back.]

  • My friends, welcome to one of the biggest mind-flogs of quantum mechanics; it's called

  • superposition -- the idea that a particle can exist in all of its theoretically possible

  • states at the same time.

  • So Schrodinger came up with this thought experiment to help folks understand it: Say you have

  • a cat and you put it in a steel chamber for an hour with a vial of deadly gas, a Geiger

  • counter, a hammer, and a tiny bit of something radioactive.

  • OK just bear with me.

  • Now say there's a 50/50 chance that one of the radioactive atoms is going to decay

  • within that hour.

  • If one of the atoms decays, the Geiger counter is going to trigger the hammer, shattering

  • the vial of poisonous gas.

  • Really, Schrodinger?

  • This is not the best way to get people behind the idea of funding the sciences.

  • So, there's a 50% chance at the end of the hour that the vial has been broken and the

  • cat is dead, and an equally good chance that the vial hasn't broken and the cat's just

  • kickin' it, wondering what's for supper.

  • But, what's actually happening in the box?

  • According to quantum mechanics, any one of those radioactive atoms would be in a superposition

  • of being both decayed and not decayed at the same time.

  • Because that's how quantum objects act.

  • So then that decayed atom will have both killed and not killed the cat, right?

  • Well that's the logical conclusion but the cat isn't a quantum object.

  • The cat is a big normal thing that obeys old-fashioned Newtonian laws.

  • So it, just like ever other cat in history is either alive or dead.

  • Schrodingers point, at least one of them is that the object is subject to two separate

  • sets of laws that can't be reconciled.

  • In order to know whether the atom is decayed or not is to open the box as see if the cat

  • is dead.

  • But in quantum mechanics, the state of superposition can't be observed.

  • So when the evil mad scientist finally opens the chamber, to observe, the superposition

  • collapses once the outcome is ensured.

  • Today, Schrodinger's Cat is talked about as some undead zombie cat or discussed at

  • being dead and not dead, alive in the box.

  • But Schrodingers point wasn't to prove you can make a cat both alive and dead but instead

  • prove that the quantum world doesn't mesh well with the normal world.

  • Alternatively the point the universe is pretty freakin' weird.

  • There are other interpretations of quantum mechanics that resolve the paradox but none

  • of them are easy to test.

  • My favorite is of course theMany Worldsinterpretation that states at the end of the

  • experiment and at the end of the superposition, alternate universes are created.

  • But in this case, one in which the cat is alive and one in which the cat is dead.

  • And to be clear I don't like this interpretation because it's the most likely one, I like

  • it because it's such a excellent plot device for science fiction novels.

  • Dreaming is one of the weirdest thing we do.

  • I mean, I don't want to diminish all the other strange crap our bodies are capable

  • of, 'cause a lot of it is cracked out on so many levels.

  • But dreams are a special kind of crazy.

  • No matter how many dreams you have in your life, every once in a while you wake up like,

  • WHAT THE HELL WAS THAT?”

  • But as with everything else, science is helping us understand why we dream, what our brains

  • are up to when they do it, and why dreaming may be critically important to the functioning

  • of our awake brains.

  • Try to stay awake for this, 'cause it's really cool.

  • People have been trying to understand dreams since--well, since there've been people.

  • But the person we associate most with the science of dreaming is probably Sigmund Freud.

  • In 1899 he wrote The Interpretation of Dreams, where he suggested that dreams were largely

  • symbolic and allowed us to sort through the repressed wishes that piled up in our unconscious

  • minds.

  • And most of those wishes involve weird sex stuff.

  • Freud was kinduva perv, if you must know.

  • It wasn't until the 1950s, when scientists became able to read the electrical activity

  • of the brain, that we began to understand what a dreaming brain was actually up to.

  • Two researchers at the University of Chicago -- Eugene Aserinsky and Nathaniel Kleitman

  • -- pioneered this research by hooking people up to the newly-invented EEG machine and monitoring

  • their brain activity while they slept.

  • What they thought they'd find was that a sleeping brain was a resting brain, but they

  • discovered exactly the opposite.

  • They found that brain activity fluctuates in a predictable pattern over a period of

  • about 90 minutes.

  • This cycle takes sleepers from an initial period of drifting off, gradually into a really

  • deep sleep with slower brain activity, back into almost-waking.

  • And this stage of sleep where the sleepers were aaaaalmost awake again was the most interesting:

  • brain activity in this phase was almost identical to when people were awake.

  • But even more weird, during this stage, the subjects became functionally paralyzed--the

  • only parts of their bodies that moved were their eyes, which darted back and forth under

  • their eyelids.

  • So Aserinsky and Kleitman called this period R.E.M. sleep, after the rapid eye movement

  • that characterized it.

  • They also called itparadoxical sleep,” because the subjects seemed to be awake, according

  • to their brain activity, even though they were basically dead to the world.

  • I guess they figured these names were better thanSexually Aroused Sleep,” which is

  • another rather common feature of this stage.

  • But another thing the scientists found was that if REM sleepers were awakened, they reported

  • having really vivid dreams that were often emotionally intense.

  • It wasn't the only stage of sleep in which the subjects dreamed, but it was the time

  • they reported having the most lifelike dreams.

  • It turns out that every 90 minutes or so, during the final stage of the sleep cycle,

  • the brain phases into the R.E.M. sleep and our brains start creating crazy narratives

  • that last maybe 20 or 30 minutes.

  • This is when you have those really vibrant dreams that can easily be confused with reality.

  • So WHYYYYY so busy, Sleeping Brain?

  • And what's so important about dreaming that you have to paralyze your entire body in order

  • to have really realistic dreams?

  • Well, there are probably several answers, but one of them is that during all periods

  • of dreaming, our brains are making important connections between real-life experiences

  • that will help us in our waking lives.

  • These days, researchers are finding that Freud was wrong about dreams in one important way:

  • We don't dream much about our hidden desires.

  • We mostly dream about what we did today.

  • While we sleep, our brains are sorting through what happened while we were awake, deciding

  • which new experiences were important enough to remember and which should get tossed, searching

  • for links between seemingly unrelated events that might be able to help us be a more successful

  • human tomorrow.

  • And it's actually really important that we do this while we're asleep, because our

  • conscious, waking brains are generally too controlling to allow this kind of creative

  • problem-solving.

  • And this dream-time activity helps our waking brains be better at things that require making

  • connections and thinking outside the box.

  • Dreams have actually been responsible for some really important inventions and discoveries

  • in history.

  • For instance, Dimitri Mendeleev came up with a system for the structure of the periodic

  • table of elements in a dream after months of grueling conscious thought was getting

  • him nowhere.

  • And research shows that our brains are much better at solving puzzles if they're allowed

  • to take a nap in the middle of doing one.

  • In a study in 2004, for instance, subjects were asked to search for links between two

  • sets of numbers.

  • The subjects who napped solved the puzzle about 60% of the time, whereas only 25% non-nappers

  • were able to do it.

  • In another study, where people were asked to find connections between seemingly unrelated

  • words, those who lapsed into R.E.M. sleep between sessions solved 40% more puzzles than

  • those who didn't.

  • So dreams are all about making associations and finding patterns that our waking brains

  • have a hard time detecting.

  • But it seems to work in slightly different ways in non-REM sleep than in REM sleep.

  • During non-R.E.M. sleep, you dream, but the dreams aren't necessarily vivid, and they're

  • often about something you've been doing or thinking about a lot.

  • During these stages, people often report dreaming about kind of boring stuff -- like if you

  • spent a lot of time in the car during the day, that night you might dream about driving

  • down a long street, stopping at a series of stop lights.

  • This might seem lame, but it's actually useful to the brain in its own way: it's

  • telling itself things it already knows--likewhen you're driving a car, you're supposed

  • to stop at the stop lights.”

  • So in non-REM sleep, it's basically reinforcing existing connections.

  • But in REM sleep, we get to test out that reinforced knowledge in a context that is

  • virtually indistinguishable from real life.

  • It's like our brain running simulations.

  • So if you've been driving to your grandparents' house in Boca Raton all day, and in non-REM

  • sleep you spend a good 20 minutes practicing stopping at traffic lights, during REM sleep

  • your brain might have you trying to steer a steamroller through Manhattan from the backseat.

  • REM dreams can be very lifelike and very stressful, but that's part of it: A vivid REM dream

  • is an opportunity to safely let us try something difficult.

  • Because our brains aren't here to make friends.

  • Our brains are here to win.