That's bullshit; I want hot chocolate.

All humor involves playing with what linguists call scripts (also referred to as frames). Basically, scripts are hypotheses about the world and how it works based on our previous life experiences. Consider what happens when a friend suggests meeting at a restaurant. Instantaneously our brains configure a scenario involving waiters or waitresses, menus, a sequence of eatables set out in order from appetizer to dessert, followed by a bill and the computation of a tip. This process, highly compressed and applicable to almost any kind of restaurant, works largely outside conscious awareness. And because our scripts are so generalized and compressed, we tend to make unwarranted assumptions based on them. Humor takes advantage of this tendency.

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It is the brain’s frontal lobes that make sense of the discrepancy between the script and the situation described by the joke or illustrated by the cartoon. This ability is unique to our species. Though apes can engage in play and tease each other by initiating false alarm calls accompanied by laughter, they cannot shift back and forth between multiple mental interpretations of a situation. Only we can do this because—thanks to the larger size of our frontal lobes compared with other species—we are the only creatures that possess a highly evolved working memory, which by creating and storing scripts allows us to appreciate sophisticated and subtle forms of humor. Neuroscientists often compare working memory to mental juggling. To appreciate a cartoon or a joke, you have to keep in mind at least two possible scenarios: your initial assumptions, created and stored over a lifetime in the temporal lobes, along with the alternative explanations that are worked out with the aid of the frontal lobes.