How many times have you been reading a book, when you come across this apologetic sentence, "No pun intended," usually following some small unintentional play on words? At least a few times. Sales of fireworks have skyrocketed. The price of yeast has risen. The frog croaked. In most serious publications, it is completely unintentional and not intended to be humorous. Or is it?
One important concept in psychology is the idea that the human brain constantly seeks out patterns in the world around it. The cognitive map is a method of organizing the information to which one is exposed. This is used to keep physical surroundings in mind. A similar concept is the schema: this is the organization of new information into the old "database." However, there is another concept which fits best: the preconscious. Unlike the subconscious, preconscious consists of non-repressed memories and information. For instance, if you are writing or talking about different varieties of cheese, you might bring different memories of cheese and cheese-based foods to your preconscious memory. You're not actively thinking about them, but if somebody asks your favorite variety, you'll probably draw the answer from your preconscious store. Or, you might warn somebody about eating a 15 cheese pizza any time soon. The memories and ideas are ready to be accessed, just waiting for you to think about them.
This extends even into word choice for writing. If I were to write an action scene, words like "Bam!" and "Pow!" would enter my preconscious and later conscious mind. Someone with a large vocabulary might recall shorter, sharper words. The question then, is this: are written puns ever unintentional? In most textbooks, the answer is probably yes. However, if your friend "accidentally" uses one, chances are it was completely intentional. Because we seek patterns, we choose words that fit the concepts best (at least, in our own minds). I'm not going to say "Butter salesmen have disseminated themselves across the nation," but "Butter salesman have spread themselves across the nation." The humorous aspect may not be purposeful, but the supposed pun is completely intentional.
I suppose you thought "Oh, he's only going to write in puns" after seeing the title. I'm a-Freud I'm going to have to disappoint you. Writing puns for any field requires more than a working knowledge of id. I'm not plotting a schema to amuse you.
Puns, therefore, derive from our need to connect things mentally. Every pun is intended.
