WASHINGTON — The difference between the sexes has long been a rich source of humor. Now it turns out, humor is one of the differences.
Women seem more likely than men to enjoy a good joke, mainly because they don't always expect it to be funny.
"The long trip to Mars or Venus is hardly necessary to see that men and women often perceive the world differently," a research team led by Dr. Allan L. Reiss of the Stanford University School of Medicine reports in Tuesday's issue of Proceedings of the National Academy of Sciences.
But they were surprised when their studies of how the male and female brains react to humor showed that women were more analytical in their response and felt more pleasure when they decided something really was funny.
"Women appeared to have less expectation of a reward, which in this case was the punch line of the cartoon," said Reiss. "So when they got to the joke's punch line, they were more pleased about it."
Women were subjecting humor to more analysis with the aim of determining if it was indeed funny, Reiss said in a telephone interview.
Men are using the same network in the brain, but less so, he said, men are less discriminating.
"It doesn't take a lot of analytical machinery to think someone getting poked in the eye is funny," he commented when asked about humor like the Three Stooges.
While there is a lot of overlap between how men and women process humor, the differences can help account for the fact that men gravitate more to one-liners and slapstick while women tend to use humor more in narrative form and stories, Reiss said.
The funnier the cartoon the more the reward center in the women's brain responded, unlike men who seemed to expect the cartoons to be funny from the beginning, the researchers said.
The new insight could improve understanding of such conditions as depression, the researchers said.
"The bottom line is that I think it contributes to the foundation of understanding individual differences in humans," Reiss said. Humor is used by humans to cope with stress and to establish relationships, and it can even help strengthen the immune system.
Reiss' team studied the response of 10 women and 10 men to 70 black-and-while cartoons, asking them to rate the jokes for how funny they were. While the volunteers were looking at the cartoons their brains were being studied with an MRI to determine what parts of the brains were responding.
In large part, men and women had similar responses to humor, using parts of the brain responsible for the structure and context of language and for understanding juxtaposition.
In women, however, some areas were more active than in men. These included the left prefrontal cortex, which the researchers said suggests a greater emphasis on language and executive processing, and the nucleus accumbens, or NAcc, which is part of the reward center.
Reiss said he was surprised at the NAcc finding. The researchers theorized that because women were being more analytical they weren't necessarily expecting the cartoons to be as funny as did the men.
Then, when they saw the punch line, the reward center lit up, indicating something pleasant and unexpected.
Arnie Cann, a psychology professor at the University of North Carolina, Charlotte, commented: "Given the findings in the current study, that women appear to use more executive functions, it could be that they are more engaged in scrutinizing the humor to decide if it fits their views on what is acceptable humor. Once they decide the humor is OK, they could be experiencing a relief-like response."
That would fit in with the finding that women experience more reward from the joke, said Cann, who was not part of Reiss' research team.
Reiss' research was funded by the National Institutes of Health.