By Armaan Singh
Laughter is one of the most universal sensations we as humans can experience. It is
simultaneously recognizable and hard to define simply. Regardless of language, religion, creed, or background, laughter is something we can all relate to. Today we ask an important question: what exactly is laughter, and what causes it? According to Merriam Webster’s Dictionary, the purpose of laughter is to show emotion (such as mirth, joy, or scorn) with a chuckle or “explosive vocal sound.”
Laughter is much more complex than simply a physical response, and can
sometimes be linked to disorders. Let’s analyze the social and neurological science of laughter further. Often, laughter is neatly divided into two categories: Duchenne and Non-Duchenne laughter. The root of laughter is “humor”, which is difficult to define and pinpoint due to its subjectivity. Humor is generally defined as the quality of being amused or feeling comic (Oxford Dictionary). However, a blueprint for humor is when you expect one thing to happen and another thing occurs and it is a genuine expression. In a joke, the comedian usually sets up a scenario where one would expect one outcome, and through a punchline will subvert the listener by detailing the opposite information that the listener expects. This is the basis of joke-telling. It sets the stage for shock-based humor and gallows humor, offshoots of standard humor that place heavy emphasis on subverting expectations. Humor as a stimulus can then provoke laughter. Duchenne laughter is often a “genuine expression of amusement and joy and is a reaction to playing and joking around; it shows up in the smiles of a child or during roughhousing or tickling.” Polite laughter is different and is called Non-Duchenne laughter. Non-Duchenne laughter is often used as a social strategy to lighten the mood, particularly in conversations that are not necessarily funny. A Duchenne smile is implicitly associated with psychological proximity and happiness cues, whereas a non-Duchenne smile is often associated with psychological distance and politeness cues. Smiles can also be categorized as ‘polite’ or ‘genuine’.
According to research, “human smiles can be genuine, easily recognized by most
observers as a “Duchenne smile.” In contrast, “non-Duchenne smiles” appear in the mouth but not the eyes and are recognized as non-genuine, often polite smiles.” (Duchenne de Boulogne, 1862; Ekman et al., 1990, 2002; Ekman and Davidson, 1993; Frank et al., 1993; Manera et al., 2011). Over sixteen types of smiles have been distinguished at the morphological level (Ekman, 1997), and it is interesting that the various types of laughter (at humorous situations, but also scornful, mocking, social, faked, etc.) remain relatively undesignated (Ruch and Ekman, 2001). The smile occurring in response to humor is the facial configuration designated (Ekman et al., 1990) as the ‘Duchenne display’ (in honor of the neurologist, G. B. Duchenne, who first described how this pattern distinguished smiles of enjoyment from other kinds of smiling). What occurs when laughter is not triggered by happiness or polite cues of Duchenne and non-Duchenne laughter and is a disorder?
The Pseudobulbar affect (PBA) is one such nervous system disorder and is a condition
that is characterized by random episodes of sudden, uncontrollable, and
inappropriate laughing or crying. The outward expression of laughter is significantly greater or above the expected response or emotion felt in the situation. Pseudobulbar affect typically
occurs in people with neurological conditions that may affect the way the brain controls
emotion. It has been linked to damage to the prefrontal cortex, and there is usually a disconnect between the frontal lobe and cerebellum in PBA. Individuals with diseases such as Alzheimer’s, dementia and multiple sclerosis can exhibit symptoms of PBA, which is often confused with depression. In depression, however, there is control over laughter and crying. Sadly, individuals with PBA avoid social situations to avoid embarrassment. Two diagnostic tools, The Pathological Laugher and Crying Scale and The Center for Neurological Study-Liability Scale are used to identify PBA. And in 2010, the FDA approved dextromethorphan/quinidine (Nuedexta), as the first drug for PBA. Studies show it helps control outbursts of crying and laughing in people with MS and ALS.
Laughter is beneficial, as it triggers an “emotional reward center” in the brain.
Research has shown that it is a potent producer of endorphins, the feel-good chemicals that originate from opioid receptors. Laughter also releases serotonin, which is a neurotransmitter affected by typical antidepressants. Laughter relaxes muscles, enhances cognitive function, and may also have an anti-inflammatory effect for your cardiac system! Neuropeptides, chemical signals to the brain, are also released to help your immune system. More often than not, it’s a good idea to grab that old book of jokes and enjoy a good laugh. “Knock, knock–who’s there?”
What did you learn?
Questions
1. What is the difference between Duchenne and Non-Duchenne laughter?
Duchenne laughter is often a result of “genuine expression of amusement and joy and is a
reaction to playing and joking around; it shows up in the smiles of a child or during roughhousing or tickling.” Non-Duchenne laughter is often used as a social strategy to lighten the mood in conversations that are not necessarily funny.
2. What is PBA?
Pseudobulbar affect (PBA) is a condition that's characterized by episodes of sudden
uncontrollable and inappropriate laughing or crying. Pseudobulbar affect typically
occurs in people with certain neurological conditions or injuries, which might affect the way the brain controls emotion.
Citations
https://academic.oup.com/brain/article/126/10/2121/314497
https://www.verywellhealth.com/laughing-disorder-5094371
https://health4u.msu.edu/articles/2019-laughter-good-for-your-brain
“Laughter.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/laughter. Accessed 26 March. 2021.
"Humor." Oxford English Dictionary Online. HUMOR | Definition of HUMOR by Oxford Dictionary on Lexico.com also meaning of HUMOR Accessed 27 March 2021.
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Photo by Alexandr Podvalny from Pexels
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