Highest functions of brain produce lowest form of wit
David Adam
Science correspondent
The Guardian, 23-5-2005, p. 6
The highest functions of our brains handle the lowest form of wit, new research suggests.
An investigation by Simone Shamay-Tsoory and colleagues shows that the ability to understand sarcasm depends on a carefully orchestrated sequence of complex cognitive skills in specific parts of the brain.
Dr Shamay-Tsoory, a psychologist at the Rambam Medical Centre in Haifa and the University of Haifa, said: "Sarcasm is related to our ability to understand other people's mental state. It's not just a linguistic form, it's also related to social cognition."
The research revealed that areas of the brain that decipher sarcasm and irony also process language, recognise emotions and help us understand social cues.
"Understanding other people's state of mind and emotions is related to our ability to understand sarcasm," she said.
The team recruited 41 people who had suffered mild brain damage following accidents or illness. Together with 17 healthy volunteers, the scientists checked how they understood neutral and sarcastic statements read by actors.
One sarcastic example was: "Joe came to work and instead of beginning to work he sat down to rest. His boss noticed his behaviour and said 'Joe don't work too hard'."
In the neutral version, Joe begins to work as soon as he arrives and his boss's reaction is the same.
The study showed that people with damage in the prefrontal lobe struggled to pick out sarcasm. The others, including people with similar damage to other parts of the brain, were able to correctly place the sharp-tongued words into context.
The prefrontal lobe is known to be involved in pragmatic language processes and complex social cognition. The ventromedial section is linked to personality and social behaviour.
Dr Shamay-Tsoory said the loss of the volunteers' ability to understand irony was a subtle consequence of their brain damage, which produced behaviour similar to that seen in people with autism
"They are still able to hold and understand a conversation. Their problem is to understand when people talk in indirect speech and use irony, idioms and metaphors because they take each sentence literally. They just understand the sentence as it is and can't see if your true meaning is the opposite of your literal meaning."
Writing in the May issue of the journal Neuropsychology, her team proposes a three-stage neural pathway in our brains that enables us to understand irony.
First the language centre in the brain's left hemisphere interprets the literal meaning of words. Next, the frontal lobes and right hemisphere process the speaker's intention and check for contradictions between the literal meaning and the social and emotional context. Finally, the right ventromedial prefrontal cortex — our sarcasm meter — makes a decision based on our social and emotional knowledge of the situation.
Experience of past situations is also important — perhaps explaining the difference in the grasp of irony on either side of the Atlantic.
"Maybe it's a cultural difference. I think the English have a more complicated and subtle sarcasm that the Americans are not used to," Dr Shamay-Tsoory said.
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