Spontaneous laughter is triggered by different favorable stimuli that can be external (e.g., humor, human interactions) or internal (e.g., positive emotions, pleasant thoughts). This is how most people see and understand laughter: If something happens then, I will laugh (or not). Although often associated, laughter and humor, however, are distinct events. You can experience humor (a stimulus) without laughter and laughter (a choice, an emotion, or a response) without humor. Humor requires high brain functions (right frontal cortex, medial ventral prefrontal cortex, the right and left posterior temporal regions, and possibly the cerebellum), which is why it varies considerably between ages, genders, cultures, etc. What is funny to some is not funny at all to others.
I love humor. It’s easy to find online nowadays, delightful to experience when you find the right type for you, powerful in personal and professional interactions, and a great way to diffuse tension and alleviate stress.
The only downside is that it’s really hard to work with if you weren’t born with a funny bone. It’s also very time-consuming. You can’t just watch a funny movie, for example, to laugh for 10 minutes. To get that, you usually need to watch the whole movie and spend 1.5 to 2 hours. It’s the same thing with jokes. They only work so many times with the same public. You either have to remember many of them or continuously spend time coming up with new material.
What makes something funny?
Funny movies and videos
If you are interested in exploring the world of humor more in-depth, consider joining a humor association and participating in their annual conference and other events. See www.aath.org (US) and humorstudies.org (Europe).
We don’t really know why genuine laughter is contagious, but it is.
Test yourself and see!
There are 3 main hypotheses for it:
Hypothesis 1: We can’t help it.
Even though we laugh from all over our brain , the areas that control laughing lie deep in the sub-cortex, and in terms of evolutionary development, these parts of the brain are ancient, and are responsible for primal behaviors such as breathing and controlling basic reflexes. This means laughter control mechanisms are located a long way away from brain regions that developed later and control higher functions such as language or even memory. Perhaps this explains why it is so hard to suppress a laugh even if we know it is inappropriate, or why the brain responds even when we smile at ourselves in the mirror or simulate laughing with enthusiasm. Once a laugh is kindled deep within our brains these ‘higher function’ brain regions have trouble intervening.
Hypothesis 2: We are tuned for laughter.
Humans may be “tuned” for laughter much in the same way that songbirds are “tuned” for song, especially their own specific family song. While birdsong of one species may sound the same to you and me, there are subtle differences between various individuals of that species. Certain nerve cells in the songbird’s brain “fire” in response to hearing his song. Perhaps humans have specialized nerve cells that respond to laughter. After all, laughter is a specialized vocalization, and we are “tuned” to respond to vocalizations with language.
Hypothesis 3: It’s because of mirror neurons.
Another possible reason why laughter is contagious is because of mirror neurons. This is addressed in an article in Explore magazine entitled Strange Contagions: of Laughter, Jumps, Jerks, and Mirror Neurons (2010) . The author, Larry Dossey, describes several cases of “laughter epidemics” and uncontrollable laughter called “laughing jags” (p. 119).
The phenomenon that laughter is contagious is attributed to mirror neurons that fire in both the individual laughing and anyone witnessing the laughter. Mirror neurons were discovered while studying the brains of macaque monkeys in the early 1990s. It was observed that the neurons on the frontal cortex of the monkey activated when he reached for a peanut. It was also observed that the same neurons fired when he merely witnessed the researcher reaching for a peanut. After such a discovery, the research was extended to humans and similar results were found.
Dossey states that researchers now assume that mirror neurons fire during empathetic reflection of facial expressions and emotions, mimicry, and the acquisition of language. The author goes on to discuss the idea that laughter is contagious because of said empathetic reflection, a psychological premise that has been scientifically validated as a result of the discovery of mirror neurons.
This may explain why and how people with a warm, genuine, voluminous laugh can get everybody around them to laugh just by laughing themselves with sincere enthusiasm.
Induced laughter is of a chemical nature e.g., by inhaling laughing gas (nitrous oxide). It has its uses in clinical settings , but is not recommended for recreational purposes because it can have nasty consequences .
Stimulated laughter happens as a result of the physical contact or action (reflex) of certain stimuli (e.g., someone tickles you). Note that for tickling to work the brain needs tension and surprise, but how the brain uses this information about tension and surprise is still a mystery . Tickling is usually a source of embarrassment when practiced with strangers, and can easily turn into a form of aggression even with people you know and care for.  Neural correlates of laughter and humor Oxford Journal – Brain a Journal of Neurology doi: 10.1093/brain/awg226 – http://lou.pm/ncl  Learn more about the science of laughter and mirror neurons at http://lou.pm/mneurons. In this article the author, Larry Dossey, describes several cases of “laughter epidemics” and uncontrollable laughter called “laughing jags” (p. 119).  Nitrous oxide in the delivery room: http://lou.pm/n2o  Abuse of N2O is bad for health: http://lou.pm/justsayno  The mystery of ticklish laughter: https://www.laughteronlineuniversity.com/mystery-ticklish-laughter/