The laughter spills out of her like a jar of coins enriching the nearby surroundings. How does this burst of vocalized joy, unique in this form only to our species, define our personalities and impact our social relationships? A recent study of humor in children explains where the funny bone is: your brain.

Humor.

Scientists define funny as:

A collection of mental processes that are in involved in both creating and perceiving an amusing stimulus, as well as the affective response in the enjoyment of this stimulus.

The length of that definition is humorous. In short, funny means enjoyment and laughter. Teasing apart how the brain processes what is funny is more complicated. We know when you hear a joke such as,

Be careful about rubbing your toes together!



Why?

Because they might get excited and undergo mitosis.

Two simultaneous things happen in your brain:

1 – detection of incongruity. The brain is trying to sort out what the process by which a cell duplicates into two genetically identical daughter cells has to do with the digits of the foot. When the play on words becomes apparent, it gives way to

2 – positive feeling state related to mirth and/or reward. In other words, because you figured out the pun, your brain activates pleasure centers to reward you. And of course, you laugh.

The first process is entirely cognitive, whereby an unexpected violation of expectation, convention, fact or intention results in cognitive arousal. The brain’s TOPA region (temporo-occipito-parietal) tries to predict the punch line. The further off it is from the guess, the funnier the joke. The fundamental component acting here is the theory of mind (TOM).

The theory of mind is briefly defined by Simon Baron-Cohen in a 2011 Nature research article as being “to be able to reflect on the contents of one's own and other's minds." Although there is some controversy regarding the difference between empathy and “mind-blindness” (or the ability not to see other people’s desires), TOM will be used here as a development marker – it is known that children around 4 years old can understand other’s mind states. An important note: autistic and children with Asperger’s syndrome do not grasp TOM and thus cannot understand other people’s emotions.

The second process is emotional. The same neurological circuits [mesolimbic dopaminergic circuit] that are responsible for giving you the tingles when you eat that piece of triple-fudge chocolate cake turn on when you understand the joke and flood your brain with dopamine – making you feel elated.

Fascinatingly, recent neuroimaging findings have found different parts of the brain light up based on personality traits, suggesting both cognitive and emotional humor can be moderated by extraversion and introversion. Since these personality traits, along with humor processing are developed in children 6-13 of age, a group of Stanford psychologists decided to test children’s humor processing, taking into account age and IQ.

The set-up.

22 children of average to gifted intelligence watched short video clips while their brains were being monitored in an MRI. The videos were either funny, neutral or positive and included scenes of people stumbling while skiing, cars accidentally running into things, kids break-dancing or a documentary style video of animals. After each video, the child would answer “yes” or “no” to whether they enjoyed the clips. Meanwhile, the parents filled out the emotionality activity sociability (EAS) questionnaire. While including only three of the four assessed factors, the EAS concentrated on emotionality, sociability and shyness.

The driving idea was that a child’s temperament would influence what he/she thought was funny.

Emotionality [level of intensity to an emotional reaction].

It turns out the higher a child scored on this scale, the funnier the clip was and the TOPA activated markedly. Even though higher scores predict increased risk for major depression and anxiety as related to negative stimuli, the opposite could be true for positive stimuli.