Colossal Questions.
Why do we get angry?
Anger might seem like it's totally a bad thing,
but it's a perfectly natural emotion.
In general, we tend to get angry for two basic reasons;
violation of expectations and blockage of goals.
A blockage of goals happens any time something
gets in the way of something you really need or want,
like if you wait in line for tickets only to find out
they're sold out.
And a violation of expectation happens
whenever we detect a disturbance in the natural order of how
we expect things to be, like when
someone breaks the unwritten rules of society,
like cutting in line.
Anger isn't just mental.
There are physical effects too.
Getting mad releases adrenaline, which makes your blood pressure
rise, your face flushed red with blood,
and causes your muscles to tense up tight.
Almost instantly, we try to assess who's to blame,
how badly it's hurt, and what happens if we act with anger.
And maybe most importantly, we try
to understand why the person did what
they did to see if it's worth getting angry over.
For instance, if a friend accidentally
hurts you while playing a game, it's probably not a big deal.
But what if they did it on purpose?
Well, then, you're much more likely to get angry about it
even though the pain was the same.
Inside your brain, the amygdala, which
is the part that deals with emotion,
will start to react within a quarter of a second
and start freaking out.
But another part of the brain springs into action too--
the frontal lobe, which controls logic and reason.
That part of the brain attempts to jump in and keep
the emotional amygdala from having an overly
angry reaction.
So while anger might seem like the stupidest human emotion,
and often times it can be, it's actually
quite a complicated balancing act
to try and react the right way to anger-inducing situations.
The whole entire reaction happens
in less than two seconds That's why the age-old advice has
always been one of the simplest ways to deal with anger.
When you get mad, just count calmly to 10
before you let yourself react.
[sighs] See?
Isn't that better?
Why do our limbs just fall asleep,
and what causes it to happen?
In order to understand why your arms and legs can fall asleep,
you have to know how your nerves work.
You see, your whole body has a system
of nerves that run through every part of our bodies
like little high waves.
When your brain sends orders to your body,
they travel along those nerves.
And when your body feels something,
your nerves can send that info back up to your brain.
Now, when your arm or leg falls asleep,
that a weird feeling is just your nerves going
crazy because something is blocking them
from being able to send messages to your brain.
The signals start to get jumbled up,
and some nerves stop sending messages while the rest fire up
randomly.
That's what causes the pins and needles
sensation we all know so well.
When all those nerve messages get scrambled up,
the brain gets confused by the bad info, which
causes all those weird feelings, like numbness, warmth,
and tingling that we call pins and needles.
We usually don't even notice the limb is falling
asleep until we try and move.
That's because when you move, you're
helping the blood in nerves to flow normally again.
That first rush of blood gives your nerves
some extra stimulation and gives you some extra tingles.
Why do we yawn, and why are these sometimes contagious?
Humans start yawning super early in life--
as in before we're even born.
That's right.
Modern technology has shown that babies inside the belly
can yawn and hiccup for at least six months before they're born.
We also don't just yawn when we're tired.
Studies have shown that we yawn when we're
getting sleepy or waking up--
really any time that our level of alertness is changing.
Experts still aren't exactly sure why we yawn,
but there's been plenty of theories throughout the years.
The ancient Greek doctor Hippocrates,
who's known as the father of modern medicine
believed that you yawned right before you got sick
as a way to remove bad air from the lungs.
But years of scientific discovery
tell us that Hippocrates probably got that wrong.
By the 1700s, experts in Europe began
to believe that yawning was a reflex meant
to increase your blood pressure, heart rate, and oxygen levels
in order to be extra alert.
But once again, more modern science
has shown that heart rate, sweating,
or electrical activity in the brain
doesn't increase when you yawn.
So that theory is out.
Today, some experts believe that yawning might just
be another way for us to communicate.
If that's true, then yawns are a non-verbal way
to show changes in our mood or surroundings.
That's why yawns can be contagious.
When we see someone else yawn, it
can cause us to feel what that person is feeling
and communicate it back with a yawn of our own--
almost like a conversation between our bodies
that we never decided to have.
Pretty weird, huh?
What causes people to talk in their sleep?
Studies showed that around 2/3 of the population
have talked in their sleep at some point in their life.
Sleeptalking, known by the fancy scientific name
of "somniloquy," usually just amounts to a few random words
or sounds spit out rather than a full-on sentence.
But occasionally, someone will carry on a whole conversation
while asleep.
Sometimes we sleeptalk in reaction
to something that happens to us in a dream.
This is called a motor breakthrough--
when your mouth and vocal chords speak the words
out loud that you're seeing in your dream.
Another common moment that we sleeptalk in
is while transitioning between the different stages of sleep.
Whenever you go from one stage to the next,
you briefly become half-awake, so that's
when you talk in your sleep.
But how does it actually happen?
Well, the truth is no one really knows why some of us
talk in our sleep.
That's because, unlike other similar issues
like sleepwalking, talking in your sleep
poses no real danger.
It's not classified as a disorder,
and doctors consider it to be just a normal occurrence.
So because it's not officially considered a disorder,
there's not nearly as much need or interest
in trying to figure it out.
But there is one thing that scientists try to make clear.
What someone says while they're sleeping is utter nonsense--
completely random.
The bits of research that has been done on sleeptalkers
have shown that there's no connection between waking
memories and the random things someone says in that state.
So rest assured your sibling isn't ever
going to hear you spill your deepest,
darkest secrets while you're sleeptalking-- just
some funny, silly sounds.
Have you ever stopped and wondered why our eyes get wet
when we weep?
The instinct to cry tears from our eyes
generally comes from one of two places;
a physical reaction or an emotional reaction.
A physical reaction that could cause you to cry
would be something like getting dust in your eye
or cutting up onions.
If you want to know more about why those kinds of things
cause you to cry, check out our episode on Cutting Up Onions.
But the kind of crying we're talking about today
is emotional crying.
So why do we cry tears when we're emotional?
In order to understand that, we need
to know how our tears work.
Think of them like a wash or bath for your eyes.
Each time you blink, a little bit
of liquid we call "tears" covers your eye to keep it clean,
moist, and protected.
After each blink, the tear drains down
the corners of our eyes through a little tunnel
called a "tear duct" that takes the tear away.
That's why we blink so much.
Each blink replenishes our eye with a fresh tear
which drains over and over.
Now, sometimes our eyes make tears
faster than our tear ducts can drain them.
That causes the tears to spill out of our eyes,
like an overflowing bathtub.
And just like that, we're crying.
People can cry after any strong emotion--
happy or sad.
You might cry tears of joy at finding your long lost
puppy or tears of sadness if a friend hurts your feelings.
OK, so that's why we cry.
But why do strong emotions cause us
to make a ton of extra tears?
Well, experts still don't know for sure,
but they have a few theories.
Some believe we cry as a way of communicating with others
that something's really wrong.
Others believe it might help you release toxins and bad hormones
from your body when you're over-stressed.
But whatever the reason, one thing is for certain--
everybody cries.
Why do we get hiccups?
People have always wondered why we hiccup.
And throughout history, we've come up with some pretty wild
stories to explain them.
The ancient Greeks believed that hiccups
were violent emotions erupting from the body,
like a cork popping from a bottle.
In some Slavic and Hungarian folklore,
people only get hiccups when someone somewhere else
is talking about them.
And in some Indian and Arabic folklore,
you just get them when someone who cares about you
is thinking of you from far away.
Nowadays, experts look for more scientific explanations.
Evidence points to spasms in a muscle called the "diaphragm."
It's the big muscle between your chest and abs
that helps you breathe.
When it spontaneously spasms, it causes
us to take in a quick breath of air.
The sudden rush of air causes a flap inside your throat
called the "epiglottis" to shut, interrupting the quick breath
and causing the [hiccups] sound that makes a hiccup a hiccup.
OK, so spasms in the diaphragm cause hiccups.
But what causes the diaphragm to spasm in the first place?
Well, that could be caused by an overly full stomach, eating
unhealthy foods, eating too quickly, or by sudden changes
of temperature inside the stomach.
Hiccups can even be caused by strong emotions,
like excitement, shock, or fear.
That's why sometimes a sudden jump scare
can cure your hiccups.
[startles] [chuckles] Sorry.
I had to try.
Speaking of cures, there's lots of possible remedies
out there but no surefire solution.
Maybe the most common cure for hiccups
is also the sweetest-- a spoonful of sugar.
Or if sweet isn't your thing, maybe
try sour with a spoonful of vinegar instead.
Not into that?
Then try peanut butter, hot sauce, honey,
or even powdered chocolate.
If you'd rather not gobble down spoonfuls of food,
try breathing slowly and deeply into a brown bag
or just take big slow gulps of water.
And if those don't work, maybe this one.
Why do we sneeze in the first place?
Basically, a sneeze is just your body's natural way
of trying to eject something from inside your nose that's
not supposed to be there.
There's lots of common things that
get into our nose and cause irritation, like pepper,
perfume, smoke, dust particles, and allergens.
When the sensitive skin on the inside of your nose
detects an unwanted substance, it sends an electric signal
to your brain.
This signal tells your brain that your nose
needs to be cleared.
Now it's time for a sneeze, so your brain
has to get your whole body onboard.
In the second or two your brain has to prep before a sneeze,
your eyes are forced shut, and your tongue pushes up
against the roof of your mouth, and your muscles brace
themselves for the ejection.
And for good reason, when you sneeze,
you're shooting air, water, and mucus from your nose
at over 100 miles per hour.
That's some incredible force.
So a big part of the reason you sneeze
is to get rid of bad particles in your nose,
but that isn't the only reason.
In 2012, researchers discovered that sneezing is your nose's
way of resetting itself.
The cells that line the walls of your nostrils
are rebooted, like restarting a computer.
And while sneezing might be healthy for you,
it does release a ton of bacteria and microbes
into the air that can spread sickness.
So sneeze with caution.
Oh, and there's also a special kind of sneezer
out there worthy of a mention.
They're called "photic sneezers,"
and you might be one of them.
These are people who sneeze when they look at a bright light
or up at the sun.
Being a photic sneezer is something
you inherit from your parents.
But experts aren't sure what about bright light
causes some people to sneeze.
They do think it affects between 20% and 35% of the population.
Some expert who loves a good-dad joke gave the photic sneeze
a clever scientific name--
autosomal dominant compelling helio-opthalmic outburst
syndrome, or ACHOO Syndrome.
[snickers fakely]
When did humans first start laughing,
and why do we love to laugh so much?
Let's start at the beginning.
When did humans start laughing in the first place?
Well, experts believe that laughter
may have evolved at two specific and distinct points
in human history.
The first type of laughter developed a couple
million years ago before language was invented
and before we were really even human.
This is the type of laughter we feel when we see something
genuinely fun or funny.
[short laugh] It evolved at the sounds
primates make while roughhousing.
Like monkeys, humans started laughing this way when danger
was low, basic needs were met, and it was a good safe time
to have some fun.
It's also the kind of laugh we use to relieve tension.
For example, it's the kind of laugh
we use after a particularly scary scene in a movie.
We laugh in a way that says, huh, I wasn't that scared.
Fast forward a couple 100,000 years
and the other type of laughter emerged in humans.
It's the kind of laughing that we
do most of the time that usually has nothing to do
with something being funny.
As humans started living in bigger groups,
we learned how to use and abuse laughter to get what we want.
This is the type of laughing people
used to hurt someone's feelings or to make someone feel better.
Fast forward another couple 100,000 years to today
and we still use both types of laughter.
The first type of laughter is obvious--
a friend tells you a joke or if you ripped your pants--
you know, funny stuff.
The second type is more subtle but also more common.
That's the type of laughter we use
when we're nervous, scared, or anytime
we laugh at something that wasn't actually a funny joke.
So why do we laugh?
Because it makes us feel safe.
It makes us feel better.
And it lets people around us know that it's
OK to let their guard down.
What causes us to get so irritable and angry when
we're hungry?
Scientists actually have a pretty good sense
of why we get so moody when we have the munchies.
It has to do with the amount of something
called "glucose" in your blood.
Glucose is another word for blood sugar
and helps keep your body running in tip-top shape.
If you have the right levels of glucose in your blood,
you'll feel fine.
But if there's too much or too little,
your body will start to have some trouble functioning.
You see, we use glucose along with fats, amino acids,
and other fuel sources to give us energy.
When those things run out, our body
tends to freak out a little bit.
Our brains rely on glucose to work right.
So when your blood sugar drops, you might start to stutter,
slur words, forget things, get dizzy,
find it hard to concentrate, and make simple mistakes.
Some of our bodies have a harder time regulating our blood sugar
levels than others.
They tend to experience more severe "hanger" and more often.
When your body realizes that it needs more glucose,
your liver starts producing its own supply
to help keep your blood sugar levels up.
Doing that triggers your body to release adrenaline
into your system, which can also cause you
to get extra angry extra quick.
That combo can lead to hissy fits we call "hanger."
So that's why we get so heated when we're hungry,
but what should we do about it?
The answer seems obvious, and, honestly, it is--
eat.
But there is a little more to it than that.
If your blood sugar drops, it might
be tempting to grab a candy bar or some other delicious, sweet,
and sugary food.
But that's not really the greatest source.
It'll cause a quick spike in blood sugar levels,
but they'll drop again as soon as the sugar rush ends.
Instead, experts suggest going for something
with more nutrients, like an apple, avocado, yogurt, nuts,
eggs, and all sorts of other healthy things to treat.
These foods have way more quality nutrients in them
and have a much more manageable amount of sugar.
So next time your stomach's rumbling
and you have an urge to freak out, just take a breath
and go find something to eat.
And, yes, even a candy bar is better than nothing.
What is tickling, and why does it tend to make us laugh?
Whenever something touches you, all the nerve endings
underneath the top layer of your skin
react by sending electrical signals up to your brain.
Those signals are sent to two different areas of the brain;
the part that controls touch and the part that
generates pleasant feelings.
Humans aren't actually the only animals who can be tickled.
Research shows that gorillas, rats, and even
dogs are all known to sometimes laugh when tickled.
There are two basic types of tickling.
The first is known as "gargalesis,"
and it's the intense kind of tickling
that happens when something tickles
a sensitive spot, like an armpit or foot,
and usually causes laughter.
The other kind of tickling is called "knismesis,"
and it happens when something moves ever
so slightly across the skin, like a feather.
This type is less likely to make you laugh
and feels more like an itch.
Despite being such a basic reaction,
experts still aren't sure exactly why
tickling makes us laugh, but they do have a few ideas.
Some scientists think it could simply
be an age-old form of social bonding.
You see, as far back as we know, babies and parents
have bonded through tickling and laughing together.
But others believe we might laugh when tickled
for a more primal reason--
survival.
That's right.
Some experts expect it might be an evolutionary trait designed
to help protect some of our most vulnerable spots,
like the neck or stomach, from a predator.
And I know what you might be thinking.
How would laughing like a maniac help us fend off an attack?
The theory is that laughing when you're tickled
sends a subconscious signal that you've
had enough, which should theoretically
shorten the attack.
It also might help explain why we sometimes
start laughing just at the threat of being tickled.
Of course, there are some people who might not
be ticklish at all, some who hate the feeling,
and others who are really good at controlling the laughter.
So please, just remember to always tickle your younger
brother responsibly.