He who laughs last didn't get the joke. She who laughs last may have used more areas of her brain while processing it.
According to a recent paper published in the Proceedings of the National Academy of Sciences, men and women get their laughs from different areas of the brain.
When researchers showed their subjects stimuli designed to be funny, fMRI images indicated activation in two sections of the female brain: the area responsible for executive functioning and the area responsible for reward processing. Meanwhile, men had no such response in either area.
Advertisement
"Even though there's a lot of equivalent behavioral data and a lot of pockets of shared activity between men and women, these differences, as we would expect, suggest that men and women approach similar stimuli with different processing strategies and approaches," said Eiman Azim, the lead author of the paper, who did the research before he received his bachelors degree from Stanford in 2003.
Azim—now a graduate student in neuroscience at Harvard—and his team showed subjects a diverse wealth of cartoons, some with word-based humor, some with image-based humor and some purposefully doctored to be unfunny, Azim said. They then observed blood flow to different areas of the brain using fMRI. The researchers compared brain activity over the course of funny cartoons and unfunny cartoons, as labeled by the subject.
The most surprising result, Azim said, was that women's reward processing center lit up when they hit the punch-line of funny cartoons.
"This region is often associated with reward prediction, so if you don't expect a reward, and you receive it, you have high activation in this region," Azim said. "We actually found that when we gave an unfunny stimulus ... [men] deactivate this region, whereas women don't.
"So basically what we conclude from these data is that men and women are activating this reward prediction region to different degrees, potentially because of a difference in expectation and prediction of future reward."
In other words, men have much higher expectations for their cartoon-reading experience than women do. Women are pleasantly surprised when they get the joke, whereas men are sorely disappointed when they do not.
The other area of a woman's brain that's tickled by humor is the prefrontal cortex. Azim said this region is responsible for many kinds of information processing, so it is hard to determine exactly what it does with humor.
"We can speculate about whether women are spending processing to deconstruct the joke or whether they are just paying more attention to the stimulus when it comes, but really we can't draw those conclusions from this study," he said.
Azim emphasized that his research is very preliminary. FMRI is a powerful tool with a powerful limitation: It can only tell researchers what area of the brain is activated, not the specific process that takes place. However, Azim said, this study does indicate that the two sexes respond differently to equivalent stimuli, and future studies may help scientists understand more macroscopic differences between men and women.
"It's been shown that women have about twice the rate of depression of men," Azim said. "And if studies like this can start to reveal differences between men and women in affective response and affective modulation, then perhaps we can start gaining some insight into why processing in these limbic regions of the brain is handled differently between the two sexes."