Israeli researchers have discovered how the brain comprehends sarcasm, a complex communication that people with damage to the prefrontal lobe of their brains cannot easily understand.
The new research, which details an "anatomy of sarcasm" that explains how the mind puts sharp-tongued words into context, is featured in May's issue of Neuropsychology, published by the American Psychological Association.
Dr. Simone Shamay-Tsoory and colleagues at the Rambam Medical Center in Haifa and the University of Haifa studied 25 participants with prefrontal-lobe damage, 16 with posterior-lobe damage and 17 healthy controls.
All participants listened to brief recorded stories, some sarcastic, some neutral, that had been taped by actors reading in a corresponding manner.
An example of sarcasm was: "Joe came to work, and instead of beginning to work, he sat down to rest. His boss noticed his behavior and said, 'Joe, don't work too hard,'" meaning: "You're a real slacker!"
A neutral example was: "Joe came to work and immediately began to work. His boss noticed his behavior and said, 'Joe, don't work too hard!'" meaning: "You're a hard worker!"
Following each story, researchers asked a factual question to check story comprehension and an attitude question to check comprehension of the speaker's true meaning: Did the manager believe Joe was working hard?
When participants who answered got the fact right but the attitude wrong, they got an "error" score in identifying sarcasm.
The Israeli psychologists who conducted the research explain that for sarcasm to score, listeners must grasp the speaker's intentions in the context of the situation.
This calls for sophisticated social thinking and "theory of mind," or whether we understand that everyone thinks different thoughts.
As an example of what happens when "theory of mind" is limited or missing, autistic children have problems interpreting irony, the more general category of social communication into which sarcasm falls.
Participants with prefrontal damage were impaired in comprehending sarcasm, whereas the people in the other two groups had no such problem.
Within the prefrontal group, people with damage in the right ventromedial area had the most profound problems in comprehending sarcasm.
The ventromedial area is the inferior (rear) part of the prefrontal cortex, and includes the cortex on top of the orbits of both eyes and the inside part of the frontal lobes.
The findings, said Shamay-Tsoory, fit what is already known about brain anatomy: The prefrontal cortex is involved in pragmatic language processes and complex social cognition, thus it followed that that participants with prefrontal damage had faulty "sarcasm meters."
At the same time, damage to the ventromedial area, which is involved in personality and social behavior, will disrupt not only understanding sarcasm but also understanding social cues, empathic response and emotion recognition.
The authors write, "Understanding sarcasm requires both the ability to understand the speaker's belief about the listener's belief and the ability to identify emotions."
The findings highlight the importance of lesion size in sub-regions of the frontal lobe because the extent of the right ventromedial lesion was significantly related to performance in the sarcasm task: The worse the damage, the greater the impairment.
"A lesion in each region in the network can impair sarcasm, because if someone has a problem understanding a social situation, he or she may fail to understand the literal language," said the chief researcher.
"This study contributes to our understanding of the relation between language and social cognition."
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26-05-2005, 17:26
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