Nurture, Not Nature: Study Says Environment, Not Genetics, Defines Sense of Humor

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1 Nurture, Not Nature: Study Says Environment, Not Genetics, Defines Sense of Humor By Jennifer Viegas - Special to ABCNEWS.com 2000 Accessed May 2012: A new study suggests sense of humor is a learned trait, influenced by family and cultural environment. The study, published in this week s New Scientist, laughs off the theory that humans possess a joke gene, because genetic factors don t seem to have any impact on humor appreciation. Cartoon Connoisseurs Researchers came to this conclusion after studying 127 pairs of female twins at the Twin Research Unit, St. Thomas Hospital, London. Seventy-one of the twin pairs were identical, meaning that they possess the same genes, while the rest of the test subjects were fraternal twins who, on average, share about 50 percent of their genes no more than do ordinary siblings. In what had to be one of the most fun scientific studies ever, the twins were asked to go into separate rooms and rate five Gary Larson The Far Side cartoons from zero to 10. Zero meant the cartoon was a boring dud, 5 indicated the joke was fair, and 10 meant it was one of the funniest things they d ever seen. Fans of The Far Side might recall the cartoons that were used in the test. Tim Spector, director of the Twin Research Unit, and lead author of the study, describes three of them: 1. A dog tethered to the mast of a Viking ship wags its tail as its owner and other Vikings return from a burning and presumably pillaged castle. 2. A group of people stands in a doorway to a room in which a composer sits at his piano. The composer s head is slumped against the keyboard and his arm, or the skeletal remains thereof, hangs to his side. The caption below reads shhhh! the Maestro is decomposing! 3. A woman stands in her living room, peering into a fishbowl; her eye magnified and distorted by the water. Meanwhile, an enormous eye fills the window of the room she s in, staring at her. No Difference Surprisingly, the identical twins shared no more common responses to the jokes than did the fraternal twins during the study. In fact, the fraternal twins often were in closer agreement as to which jokes seemed funny, and which cartoons appeared to be a waste of paper.

2 We found that between one-third and two-thirds of the variability in reaction to the cartoons was due to shared environmental effects such as family upbringing, says Spector. Genetic factors did not appear to contribute at all. He adds that teachers, classmates, dad s jokes, culture and religion all help to shape sense of humor. Why The Far Side? One of the reasons Larson s cartoons were chosen for the study is that they contain cognitive, or off the wall, humor. Spector explains, Cognitive is the good sensation that comes over you when you get the joke. Such a sensation comes from the sudden mental integration of incongruous ideas, attitudes or situations. Spector chose to use this kind of humor for the study because responses to it are variable. He says some people love The Far Side, for example, while others just don t get it at all. Also, cognitive jokes make good test material because they re generally not offensive. The three other defined humor types are not quite as sophisticated. Conative humor produces a smug feeling of superiority from other people s misfortune, such as when we laugh at someone tripping on a banana peel. Affective humor involves racial or smutty jokes. Orectic humor combines the previously two mentioned types. Men Are Another Story The participants in this study were all females, but what about males? Spector says other research indicates that both men and extroverted women tend to appreciate orectic jokes. It s not clear why, though. Further, the mirth-meter for men and extroverts seems to depend upon, as Spector puts it, the cognitive demand of the stimulus and the individual s psychometric abilities. That s a scientific way of saying it helps to be smart when presented with a more subtle, sophisticated cartoon or joke. There is also evidence that humor appreciation varies with age and personality. For instance, a more staid person is likely not to guffaw at a liberal, racy joke. Robert Plomin, a behavioral geneticist at the Institute of Psychiatry in London, says Spector s research is interesting, because twin studies of personality traits almost always show genetic effects. However, he thinks a larger research project is needed to confirm the findings. Spector and his team next hope to test the other types of humor, including sexual innuendo. Brain Damaged People Prefer Slapstick Humor Last year, scientists identified the part of the brain responsible for humor appreciation. As it turns out, the right anterior frontal lobe is our chuckle-producing chunk of gray matter,

3 according to researchers at the Rotman Research Institute of the University of Toronto. When this part of the brain is damaged such as by stroke, tumor or surgical removal humor appreciation is impaired. The researchers came to this conclusion after asking study participants to choose the appropriate punch line for a written joke. For example: The neighborhood borrower approached Mr. Smith Sunday noon and inquired, Say Smith, are you using your lawnmower this afternoon? Yes, I am, Smith replied warily. Then the neighborhood borrower answered: A. OOPS! as the rake he walked on barely missed his face. (slapstick) B. Fine, then you won t be wanting your golf clubs, I ll just borrow them. (correct, because it requires the reader to look for a higher level of meaning amongst the other possible responses) C. Oh well, can I borrow it when you re done, then? (straightforward logical choice) or D. The birds are always eating my grass seed. (illogical) Test results indicated that people with damage to the humor appreciation part of their brain tended to choose the slapstick ending.

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