Intro:
Hello everyone and welcome to Six Pack of Facts, a weekly way of expanding your brain six refreshing facts at a time. My name is Alex and this week, it’s ecstasy and agony. We’re exploring the gamut of human emotion and digging into some hilarious and sad facts about crying and laughter.
Topic One: Crying
One: Three Types of Tears
Before we get into why we cry, let’s examine what we cry. Although it might seem like every tear is created equally, there are actually three different types of tears that flow from our ducts.
First, basal tears. These are your everyday, run-of-the-mill tear, and our eyes actually swim in them all day. Basal tears are full of mucus, water, and salt to lubricate the eye and to fight off infection. These tears also contain oil that helps keep the liquid from evaporating as they spread evenly over the surface of the eye as you blink.
Next, reflexive tears. These tears flow to wash the eye of irritants. That pesky eyelash that drove you absolutely NUTS the other day? You have reflexive tears to thank for washing it away.
Finally, emotional tears. This is the main show. The tears that flow when we experience feelings of sadness, happiness, anger, grief… any strong emotion, really. They contain the same basic chemical makeup of basal and reflexive tears, but also have more natural painkillers and stress hormones.
Two: Why We Cry
Basal and reflexive tears are pretty straightforward. But emotions aren’t always that straightforward, and exactly why humans cry isn’t either.
Babies cry… a lot. And for good reason; it’s one of the only ways they can communicate a need. But we continue crying our entire lives, far past the stage where we’re need to shed a few tears to signal hunger. There’s no clear-cut reason why, but it could have something to do with an evolutionary adaptation to signal distress without attracting predators. Usually, adult crying isn’t paired with the same type of wailing as infants produce. Tears could be a visual signal to others that a person is currently dealing with something that is temporarily beyond their control — a bit of a call for empathy, if not help.
A crying person also sends different social and emotional signals to onlookers, according to a 2016 study. When approached by visibly crying people, participants in the study perceived them as friendlier and felt a greater personal connection, making them more willing to provide assistance.
Then there’s the case of crying alone. Which everyone has done. Don’t even try to lie about it. And there’s a good reason for that! Emotional tears, as we covered before, include higher amounts of leucine-enkephalin, an endorphin that relieves pain, and oxytocin, a mood-boosting hormone. The verdict is out on whether or not this legitimately affects your mood in a measurable way, but the chemistry — and the simple fact that we anecdotally do feel better after a good cry — certainly support the thought.
One thing is for sure, though — crying is not a sign of weakness. Everyone cries. It’s normal. It’s healthy. So, let it out.
Three: Animal Crying
Like I just said, crying is a very normal experience for humans. But the rest of the planet’s creatures? Not as much. In fact, humans are the only known creature to actually cry tears of sadness. Animals will let out wails of fear or alarm or even need, but there aren’t any tears to back up those sounds.
In one instance, Koko the gorilla, one of the most famous primates in history, is known to have expressed deep sadness after learning that her first kitten died (just saying that sentence is almost enough to make me cry) and after learning of the death of Robin Williams (the two had met years before and bonded). In both cases, Koko let out sob-like sounds and even used sign language to tell her keeper the word “cry,” but no tears were shed.
Segue:
Dry those tears, my friend. We’re switching to something that’s decidedly a little lighter. Let’s laugh.
Topic Two: Laughing
One: Origins of Laughter
Much like crying, the origins of laughter stretch far back into our history — between 10 and 16 million years ago. The first “laughter” probably originated from labored breathing during bouts of play between early mammals. The sounds, shared by two individuals and coming from a positive interaction, would have strengthened the bonds between the two.
But the true development in laughter came when mammals learned to make the noises, now closely linked to positive social bonds, without first having to experience some sort of underlying emotion. That ability increased vocal control and allowed those brains to grow more complex, providing the necessary runway to true language. It also allowed for the use of fake laughter, which is acoustically distinct from true laughter even in the primate world, but often provides a similar positive social outcome, nonetheless.
Two: Fake Vs. Real
Fake laughs are sometimes a good tool for socially lubricating a situation, but that doesn’t mean our brains are truly fooled. A study conducted by the University of Royal Holloway London showed genuine laughter produced a different neurological response from canned laughter.
Even more interestingly, the fake laughter activated areas in the brain associated with mentalizing in an attempt to understand the fake laugher’s emotional state. This shows that not only can the brain understands the difference between real and fake laughter, it tries to decode the performance to get to the core of what the other person is really feeling. Some of those areas included regions that control movement and detect sensation, possibly showing that trying out the fake laugh ourselves helps us understand its meaning.
Three: Animals and Laughter
We ended crying with animal facts, so it’s only fitting we return back to that kingdom to finish off the episode. Scientists have identified 65 different species of animals that have their own distinct laughter. Going a step further, dolphins are known to play pranks on their friends and even humans, showing they understand — at least to a certain extent — humor.
Let’s take this six pack out with a laugh. Here are just a few animal chortles.
A kea, a parrot native to New Zealand.
A chimpanzee.
An orangutan.
And the laughter of a rat that is, no joke, giggling in ultrasonic frequencies after being tickled.
Outro:
Research Links
Crying
Cleveland Clinic — Why We Cry and What Tears Are Made Of
Mental Floss — 7 Teary Facts About the Science of Crying
The Cut — Why Do We Cry to Express Feeling Overwhelmed?
Laughing
NPR — Dozens Of Animals Laugh Too, Study Shows
Science Daily — Fake Laughter Doesn't Fool the Brain, Research Reveals
The Conversation — The Evolutionary Origins of Laughter Are Rooted More in Survival Than Enjoyment
