Israeli psychologists draw conclusions from how brain-damaged people comprehend sarcasm - or not

May 23 2005

The ability to comprehend sarcasm depends upon a carefully orchestrated sequence of complex cognitive skills based in specific parts of the brain. Yeah, right, and I’m the Tooth Fairy. But it’s true: New research details an “anatomy of sarcasm” that explains how the mind puts sharp-tongued words into context. The findings appear in the May issue of Neuropsychology, published by the American Psychological Association (APA).

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.

Simone Shamay-Tsoory, PhD, and colleagues at the Rambam Medical Center in Haifa and the University of Haifa, studied 25 participants with prefrontal-lobe damage, 16 participants 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. Here is an example of sarcasm: “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!” Here is a neutral example: “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 answered got the fact right but the attitude wrong, they got an “error” score in identifying sarcasm.

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 fit what we already know 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.

In sum, Shamay-Tsoory and his/her colleagues propose a neural network for processing sarcastic utterances:

1. The left hemisphere language cortices interpret the literal meaning of the utterance; The frontal lobes and right hemisphere process the intentional, social and emotional context, identifying the contradiction between the literal meaning and the social/emotional context;
2. The right ventromedial prefrontal cortex integrates the literal meaning with the social/emotional knowledge of the situation and previous situations, helping the listener determine the true meaning.
3. Shamay-Tsoory says, “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. Thus this study contributes to our understanding of the relation between language and social cognition.”

Article: “The Neuroanatomical Basis of Understanding Sarcasm and Its Relationship to Social Cognition,” S.G. Shamay-Tsoory, PhD, and R. Tomer, PhD, Rambam Medical Center and University of Haifa, and J. Aharon-Peretz, MD, Rambam Medical Center; Neuropsychology, Vol. 19, No. 3.

Full text of the article is available from the APA Public Affairs Office or at http://www.apa.org/journals/releases/neu193288.pdf.