The General Assembly of the United Nations has proclaimed March 20 the International Day of Happiness; more than a frivolous feel-good holiday, the aim is to inspire 100 million to promote the universal goal of happiness and well-being around the world.

And while the U.N. admirably frames the day as way to talk about a more “inclusive, equitable and balanced approach” to the economic growth that can lead to more global happiness, we're taking another approach. We’re talking laughter.

But there's a funny thing about laughter: It's so much more than an indication of happiness.

Laughing serves a social function. Some suggest that the first human laughter was a group ­gesture of relief at the passing of danger; and since laughter relaxes the biological fight-or-flight response, laughter may indicate trust in one's company.

Likewise, many researchers think that laughter is connected to bonding.

"Laughter occurs when people are comfortable with one another, when they feel open and free. And the more laughter, the more bonding within the group," says cultural anthropologist Mahadev Apte.

Behavioral neurobiologist and expert laughter researcher (that's a thing) Robert Provine believes that laughter serves as a social signal. And indeed, other scientists concur; studies show that people are 30 times more likely to laugh in social settings than when they are alone.

Laughter is part of a universal human language. It is understood across cultures ... and unlike words and syntax, which we have to learn, we are born with the capacity for giggles and tittering.

When we laugh, it happens unconsciously. We don’t think, “Hey, that’s funny, I’ll respond by laughing.” Although we can consciously be “in the moment” of our laughter, we can’t make true laughter just happen.

And while laughter isn't always sparked by happiness, it often ends up there. Some experts believe that laughter is used to process things that are difficult to understand. Consider the nervous laughter during an intense event or the seemingly out-of-place laughter during funerals. These are the moments in life where things don't make sense, and laughter is the behavior that evolved to respond to such times.

In these cases, maybe laughter can be best considered a defense against suffering and despair; as Psychology Today notes when addressing the topic of tittering, “If we can joke about a disappointing or traumatic event, we'll often find ourselves feeling that what's happened to us isn't so bad and that we'll be able to get through it.”

And then, happiness ensues.

Laughter and your brain

While we know that ce­rtain regions of the brain host certain functions, researchers have found that the production of laughter happens in various parts of our gray matter. The relationship between laughter and the brain is not fully understood, but some things are known. Although emotional responses are thought to be distinct to specific sections of the brain, laughter appears to be created by a circuit that runs through numerous areas. Furthermore, the limbic system – the complex network of nerves beneath the cerebral cortex that deals with instinct and mood – seems to be central in the process of laughing.

The average human laughs 17 times a day, and aside from stress-induced laughter, most laughter is a reaction to humor. Upon a funny scenario, more than a dozen facial muscles contract and the zygomatic major muscle becomes stimulated, resulting in a smile. The epiglottis interferes with the larynx and disrupts the respiratory system just enough so that air intake becomes irregular, making the laugher gasp.

When things really get going, the tear ducts are activated, leaving many of us laughing until we cry.

Provine did a study on the sonic structure of laughter and found that all human laughter consists of basic short notes repeated every 210 milliseconds. Laughter can be comprised of "ha"s or "ho"s, he says, but not both. Provine also says that we have a "detector" that reacts to laughter by triggering other neural circuits in the brain, which ends up generating more laughter. This explains how sometimes when we start laughing, we can’t stop; why this seems to happen so frequently in church and lecture halls has yet to be determined.

A wonderful thing about laughing – aside from just the pure pleasure of it – are the health benefits bestowed by the act; it can actually change your body. Consider the following:

  • It can stimulate your heart, lungs, muscles and endorphin release by enhancing your oxygen intake.
  • It relieves your stress response, leading to feelings of increased pleasantness.
  • It can tame tension by stimulating circulation and helping muscle relaxation, both of which help reduce some physical symptoms of stress.
  • It may improve your immune system. The Mayo Clinic tells us that negative thoughts “manifest into chemical reactions that can affect your body by bringing more stress into your system and decreasing your immunity.” Conversely, positive thoughts release neuropeptides that help conquer stress and possibly other stress-related illness.
  • It potentially soothes pain by encouraging the body to produce its own natural painkillers.
And perhaps loveliest of all; laughter is infectious. The simple act of laughing can help not only you, but those around you. It's the best kind of contagion. Case in point? Watch the video below. We dare you not to laugh:

Related on MNN: