Our capacities to communicate covertly, out of view of social reporting, are central to our abilities to coordinate to hypocritically pretend to support norms while actually evading them. Like laughter and eye-contact, sarcasm seems a central supporting skill. Here is some of what we know about sarcasm:

According to one study of a database of telephone conversations, 23 percent of the time that the phrase “yeah, right” was used, it was uttered sarcastically. Entire phrases have almost lost their literal meanings because they are so frequently said with a sneer. … Brains have to work harder to understand sarcasm. …

Lsten[ing] to complaints to a cellphone company’s customer service line, … students were better able to solve problems creatively when the complaints were sarcastic as opposed to just plain angry. … The mocking, smug, superior nature of sarcasm is [sometimes] perceived as more hurtful than a plain-spoken criticism. … “You’re distancing yourself, you’re making yourself superior,” Haiman says. “If you’re sincere all the time, you seem naive.” …

We’re more likely to use sarcasm with our friends than our enemies, … [New York students] were more likely [than Memphis students to suggest sarcastic jibes when asked to fill in the dialogue in a hypothetical conversation. Northerners also were more likely to think sarcasm was funny. …

Haiman lists more than two dozen ways that a speaker or a writer can indicate sarcasm with pitch, tone, volume, pauses, duration and punctuation. … Expressions around the mouth, as opposed to the eyes or eyebrows, were most often cited as a clue to a sarcastic statement. (more; HT David Brin)

Note that higher status and IQ cultures tend to use sarcasm more, just as smart folks tend to lie more, even though they are no better at discerning lies (source: Triver’s new book).