Fart. Booty. Tinkle. Weiner. We know these words have the ability to make otherwise mature individuals laugh, but how? And why? Is it their connotations to puerile activities? Is it the sound they make? And if an underlying structure can be found to explain why people find them humorous, can we then objectively determine a word funnier than bunghole?

Chris Westbury, a professor of psychology at the University of Alberta, believes we can. With co-author Geoff Hollis, Westbury recently published a paper ("Wriggly, Squiffy, Lummox, and Boobs: What Makes Some Words Funny?") online in the Journal of Experimental Psychology: General. The two analyzed an existing list of 4997 funny words compiled by the University of Warwick and assessed by 800 survey participants, whittling down the collection to the 200 words the people found funniest. Westbury wanted to see how a word's phonology (sound), spelling, and meaning influenced whether people found it amusing, as well as the effectiveness of incongruity theory—the idea that the more a word subverts expectations, the funnier it gets.

In an email to Mental Floss, Westbury said that a good example of incongruity theory is this video of an orangutan being duped by a magic trick. While he's not responding to a word, clearly he's tickled by the subversion of his own expectations:

With incongruity theory in mind, Westbury was able to generate various equations that attempted to predict whether a person would find a single word amusing. He separated the words into categories—insults, sexual references, party terms, animals, names for body parts, and profanity. Among those examined: gobble, boogie, chum, oink, burp, and turd.

Upchuck topped one chart, followed by bubby and boff, the latter a slang expression for sexual intercourse. Another equation found that slobbering, puking, and fuzz were reliable sources of amusement. Words with the letters j, k, and y also scored highly, and the vowel sound /u/ appeared in 20 percent of words the University of Warwick study deemed funny, like pubes, nude, and boobs.

In the future, Westbury hopes to examine word pairs for their ability to amuse. The smart money is on fart potato to break the top five.

[h/t Live Science]