has owned it for years now. I'm talking about expressing too much emotion, usually in public

and in weird and often insensitive ways.

Such regrettable outbursts are not unique to celebrities, of course, and they can be

enough to make us think of our emotions as irrational. But they're not... well, not usually.

When they're not getting the better of us, they have work to do. Part of their job is

to provide the energy and motivation that lets us meet our goals and our needs, and

despite the occasional public fail, they often improve our performance in a given situation.

So emotions play an important role in how we think and behave. Of course, when they

blow up and someone screams at a flight attendant or punches a paparazzo or jumps on stage and

grabs the mic away from a teenager in the middle of her acceptance speech to say that

someone else deserve the honor more - all hail Beyoncé - you're kind of off the rails

of normal emotional function.

Okay, definition time, general idea. Emotion is a mind and body's integrated response to

a stimulus of some kind. Emotions involve physiological arousal, expressive behaviors

and conscious experience. These can be short flashes or long, lingering responses, and

they can be very clear or very confusing. Say, you're walking home at night and you

hear footsteps behind you. Physiological arousal occurs in the form of your heart pounding,

your expressive behaviors could be like quickening your pace or moving toward a streetlight,

and your conscious experience may include thinking "Oh I'm... I'm... gonna get mugged

now? Is this like a werewolf behind me?" Feeling, you know, fear and panic.

We know those three pieces are there, but psychologists are still puzzling out exactly

how they fit together. How do thinking and feeling interact? Which one comes first? And

do these bodily reactions - the pounding heart, the need to pee, the sweaty palms - come as

a result of the thought "I"m scared", or did my tweaking out body trigger the thought in

my brain? These are just some of the questions that we'll be looking at in this messy, exhilarating,

and terrifying world of emotions - no one gets out unscathed.

[Intro]

Our emotions represent and construct a big part of who we are. Think of how boring we

would be - how boring the world would be without joy, embarrassment, heartache, or fear. What

would motivate us to make decisions, be cautious, or bold, or strive to understand each other?

What would keep our humanity intact? Where would punk rock come from? No doubt, we need

our emotions, but how do they work?

Well, like, apparently everything in psychology, there are a few different theories. In the

late 1800s, pioneering American psychologist William James suggested that our feelings

follow our bodily reactions to external situations; that, for example, you feel sad because you

are crying, or you're scared because you're shaking like a leaf. This idea was also proposed

by Danish psychologist Carl Lange, and so, this concept that physiological arousal precedes

emotion is called the James-Lange theory.

But American physiologist Walter Cannon wasn't feeling it. He thought that too many of the

body's reactions were too similar: a racing heart, fluttering stomach, and sweaty hands

could be attributed to passion, fear, excitement, or anger. So how could they cause such different

emotions? His colleague, Philip Bard, agreed, concluding that bodily responses and emotions

occur separately, but simultaneously - and this idea is the base of the Cannon-Bard theory

of emotion. In other words, a racing heart doesn't cause fear, nor does the feeling of

fear result in a racing heart, rather, both things just happen together.

Today, most psychologists agree that our emotions are also tangled up with our cognition: whether

or not we're afraid of a dog on the sidewalk depends a lot on whether we're interpreting

the animal's behavior as threatening or friendly, probably also, what our personal history with

dogs is. In the 1960s, American psychologist Stanley Schachter and Jerome Singer interpreted

this idea that cognition can define emotion, into what they called their "two-factor theory".

They believed that to experience emotion, you must both fear physiological arousal,

and cognitively label that arousal. And again, please remember that in psychology, arousal

is different from how you're used to using it. Here, arousal can be thought of as activation

or stress, or even energy - an increase in reactivity or wakefulness that primes us for

some kind of action. So sometimes, arousal can spill over from one event to the next:

say you just watched a heated soccer match, and you're all revved up, and someone looks

at you funny. Suddenly, you might label that lingering arousal as anger, and the next thing

you know, the whole stadium is one big rioting aggro chain reaction.

Schachter and Singer examine this so-called "spillover effect" with an experiment that

involved an usual combination of college guys and drugs. First, they injected a bunch of

college guys with the hormone epinephrine. This is basically adrenaline, and as you yourself

have probably experienced, it induces a level of physiological activation that can go any

number of ways emotionally. But then they threw a curve ball - some of the subjects

were told to expect symptoms of feeling all revved up, while others were told the injection

wouldn't produce any effects at all. Then, after being injected, each subject was left

in a waiting room, and with them in the room was an actor, pretending to wait as well,

and acting either all jerky and irritated, or super happy and euphoric. So the dude's

just sitting there, jacked up on this hormone, and his heart is racing, and his cheeks are

all flushed, and in the case where the subject was told not to expect the effects, the study

found that the guy would actually adopt the emotion of the actor in the room, becoming

happy or testy, depending on how the person was acting. His body was having a physiological

response to the hormone, but he ended up effectively deciding which emotion he was feeling. But,

if the subject had been told that the injection would make him feel all pumped up, he'd actually

report very little emotion, just because he was blaming that racing heart and flushed

face on the drug, not a particular state of mind. So in terms of the two-factor theory,

the cause of physiological arousal had to be identified before a person could feel and

label the response as a particular emotion.

To Schachter, Singer, and their disciples, this meant that arousal spurs emotion, but

cognition directs it. And yet, some researchers like Polish-born American psychologist Robert

Zajonc, contend that all emotions are the result of just putting a name to our arousal

- he suggests that many of our emotional reactions occur separately, or even before our cognition

kicks in. If you hear a sudden crash outside your window, you'll automatically react with

a jolt before your brain has the chance to think, "Gee, what was that crazy noise? Should

I feel startled?" This is, in part, because when it comes to emotions, it's thought that

our brains process sensory input by two different kinds of roots - top-down, or bottom-up approaches,

and neuroscientists can actually chart these two pathways in action. Some bigger, more

complex feelings, like love and hatred take what we call the "high-road." Say, you read

a love letter from your sweetie. You can pin that mushy feeling in your heart to the sensory

stimulus of reading traveling from your eyes all the way through your thalamus to your

brain's cortex. There, it can be analyzed by means of your cognitive process, perhaps,

consciously, perhaps implicitly - and labelled with, like, "Aw, so sweet," at which point,

it heads to your limbic system, the central brain region that drives emotion, motivation.

At that point, you respond with all the warm-fuzzies.

Other emotions, like simple likes, aversions, and fears, don't have to involve actual thinking,

and take a sort of "low-road" neural path. Like, that crash outside, or a baseball flying

at your head. Such "jump-out-of-your-chair" stimuli bypass the cortex and zip right from

the ear or the eye to the amygdala in the limbic system. It's a knee-jerk reaction that

allows us to react quickly, often in the face of potential danger. In other words, that

slower, high-road cortex route allows thinking about feeling, while the quick low-road shortcut

allows instant emotional reaction.

The stomach flip that happens when you see your ex, or the ten thousand pee breaks you

gotta take before you give a speech, or your heart racing after a really good kiss - it's

hard to argue with the fact that we often feel emotions with our bodies as much as with

our brains. And you can thank your autonomic nervous system the next time you're freaking

out or trying to calm yourself down. Perhaps, you recall when we talked about the roles

of the sympathetic and parasympathetic branches of our autonomic nervous system. The sympathetic

division is what arouses you in a crisis - it makes you hyper aware, makes your heart rate

and breathing increase, spikes your blood sugar for extra energy - all that fun stuff.

It's like a pit crew readying you for action, and once it's done its job and the danger

has passed, the parasympathetic division steps in and talks you back down from the edge,

slowing down your heart and breathing rates, and shutting off those stress hormones. Generally,

rubbing your back and being all, "Everything's gonna be okay, baby." What you need is the

right degree of arousal for the situation: for example, if you're navigating through

fast moving traffic in an unfamiliar city, you wanna hit the sweet spot of optimal arousal

that allows you to focus your attention without either freaking out or getting all mellow

and sleepy.

Like we said before, there's a lot of overlap in the symptoms of different emotions. If

you monitor the heart rate, breathing, and perspiration of a group of people who are

watching three different movies, you probably couldn't tell who was watching the grisly

horror movie, an angry fight, or a hot sex scene. Fear, anger, and sexual arousal often

deliver some of the same biological signals. But those emotions certainly feel different

to the people experiencing them, just as they usually look different to others observing

their expressions. And though differences in emotion can appear subtle, or even undetectable

on brain scans, many of them do show distinctive patterns. For most people, positive feelings

tend to show more activity in the left frontal lobe, while negative ones show up more in

the right frontal lobe. And someone who's very afraid will show increased activity in

the amygdala, our more primal emotional center.

Emotions are fascinating things that drive us to do all sorts of brilliant and weird

stuff. Understanding them and being able to read them both in yourself and others is vital

if you wanna make it through even an average day. But misreading your emotions or someone

else's can be confusing - even dangerous - and it's just one of the things that we'll be

looking at next week.

Today, you learned about what emotions are, how they work, and why we need them. We talked

about the James-Lange, Cannon-Bard, Schachter & Singer, and Zajonc theories, and we also

looked at the relationship between cognition and emotion, and how the autonomic nervous

system mobilizes emotion. Thanks for watching, especially to all of our Subbable subscribers

who make Crash Course possible - to find out how you can become a supporter, just go to

Subbable.com.

This episode was written by Kathleen Yale, edited by Blake de Pastino, and our consultant

is Dr. Ranjit Bhagwat. Our director and editor is Nicholas Jenkins, the script supervisor

is Michael Aranda, who is also the sound designer, and the graphics team is Thought Café.