Back in 1939, and contrary to rumor, David O. Selznick was NOT fined $5,000 for undermining the morals of America and putting out a movie with these eight words: "Frankly, my dear, I don't give a damn."

In fact, the words "hell" or "damn" were allowed in movies as long as their use "shall be essential and required for portrayal...provided that no such use shall be permitted which is intrinsically objectionable or offends good taste."

This bit of dialogue, spoken by a certain leading man, was voted the Number One movie line of all time by the American Film Institute. It sticks with us, not because of its rumored shock value, but because of its passion.

Rhett really means that he doesn't care anymore.

Swearing, it turns out, is persuasive.

According to Psyblog, researchers have discovered that light swearing at the beginning or end of a speech makes it more persuasive to listeners.

Listeners attribute the mild cuss to passion and that makes them more interested in your argument. If you care that much (they reason), they should listen up and treat your remarks seriously.

Of course, you shouldn't launch into a Scarface-style #$%@ rant. That would be unprofessional and offensive. You'll lose people's respect, not gain their favor.

In the study, Scherer and Sagarin (2006) divided 88 participants into three groups to watch one of three slightly different speeches. One contained a mild swear word at the beginning, one had a mild swear word at the end, and the other speech did not contain any swear words.

Here's an example of the line containing the mild swear word:

"...lowering of tuition is not only a great idea, but damn it, also the most reasonable one for all parties involved."

Participants were most influenced by the speeches with the mild profanity at the beginning or the end.

It seems the listeners were more persuaded because they thought the cursing speakers felt more intensely about their speech subject.

Another upside of swearing is that researchers have discovered that people who know a lot of curse words also know many other kinds of words: their vocabularies are larger than non-swearers.

So remember, a well-placed profanity or obscenity at the start or end of your talk can increase audience interest in your topic because it reveals your passion.

Just avoid a withering, blistering blast of filthy, foul language. Moderation in all things, my friends.