Sarcasm is lost on many people, in some cases more than others, because they may be missing part of a complex set of cognitive skills based in specific parts of the brain.
A new study by Israeli psychologists, using patients with damage to different parts of their brains, details an "anatomy of sarcasm" to explain how the mind puts sharp-edged words into context.
The psychologists write in the May issue of the journal Neuropsychology that for sarcasm to register, the listener must grasp the speaker's intentions in the context of the situation. This calls for both sophisticated social thinking and appreciating a "theory of mind," that different people think different thoughts.
"To detect sarcasm, irony and jokes, and to better understand what people mean when they talk, we must have empathy," said researcher Simone Shamay-Tsoory of the University of Haifa and lead author of the study.
The right hemisphere of the brain generally handles emotional processing, and the prefrontal cortex -- the part of the brain just behind the eyes and forehead -- deals with personality and social cues.
So the researchers expected that people with damage to the right frontal lobe of the brain would have the most difficulty comprehending sarcasm.
To test this, they did experiments with 25 patients with damage to the prefrontal cortex, 16 patients with damage to the posterior lobe of the brain and 17 healthy controls.
All were read brief scripts presented in both a sarcastic and literal vein.
For instance, in the sarcastic situation, a man arrives at work and instead of starting his job, sits down to rest. His boss notices his behavior and says: "Joe, don't work too hard!" -- meaning, of course, just the opposite.
Then, in a neutral counterpart, Joe arrives at work and immediately goes full speed ahead, and his boss cautions him: "Joe, don't work too hard!"
Following each presentation, the researchers asked a factual question to check if the subject understood the story, and an "attitude" question to check if he or she appreciated the boss' true meaning. If they got the facts of the story right, but the attitude wrong, they got an "error" score for identifying sarcasm.
To measure the ability to have empathy and infer another person's thoughts, the researchers read another set of anecdotes like this: Two boys in a school bathroom talk meanly about another boy, who suddenly emerges from a stall, where, unknown to the first two boys, he was listening.
The researchers then asked the participants questions such as whether the boys said something they shouldn't have and why they said it.
The patients with prefrontal lobe damage had difficulty comprehending the sarcasm as well as feeling empathy, while the other two test groups had no such problems. And those who had damage in the right rear part of the prefrontal cortex had the most faulty "sarcasm meters." The worse the damage was, the greater the impairment.
Shamay-Tsoory said that damage in each region of the network "can impair (understanding of) sarcasm, because if someone has a problem understanding a social situation, he or she may fail to understand the literal language. Thus, this study contributes to our understanding of the relationship between language and social cognition."
THE BRAIN AT WORK
A group of Israeli psychologists mapped out this pathway through the brain to appreciating sarcasm: