From the page: "Swearing "recruits our expressive faculties to the fullest", writes Harvard psychologist Steven Pinker in his new book, The Stuff of Thought.

Yet despite being a showcase for creativity, swear words are taboo in virtually all societies, even though their subject matter - usually sex or excretion - describes activities fundamental to human existence. So why are we such potty-mouths, and what gives certain words the power to shock?

One theory is that cussing is the form of language that comes closest to a physical act of aggression. When you swear at someone, you are forcing an unpleasant thought on them and, lacking earlids, they are helpless to repel this assault. "It's a substitute for physical violence," says Timothy Jay, a psychologist at the Massachusetts College of Liberal Arts in North Adams. "From an evolutionary point of view, it's an advantage for us to be able to say 'fuck you' from across the street," while not having to worry about getting instantly punched or kicked by the disgruntled recipient."