While comedians think up jokes, activity rises in brain areas involved in reward and making links between opposing ideas

Scientists claim to have detected the first stirrings of neural activity that flicker across the brain when a person thinks up a joke.

The signature points to what the researchers call the “neural genesis of a joke” and involves areas of the brain that deal with associations between disparate ideas and feelings of reward.

Irving Biederman and Ori Amir at the University of Southern California scanned the brains of 22 improv comedians who had been asked to think up funny and boring captions to go with cartoons of people in various situations.

When the comedians came up with funny punchlines, the scientists saw activity rise in parts of the brain used to make meaningful links between opposing or distinct ideas. Activity in a separate brain region, the ventral striatum, which is involved in reward, also rose and got stronger the funnier the comedians rated their captions.

While more than 20 studies have looked at the brain circuitry linked to appreciating a joke, the scientists claim theirs is the first to investigate the neural basis of humour creation.

“Conceiving funny ideas involves activation in semantic association regions where remote associations are linked in a meaningful way,” said Amir. “Greater activation in those regions results, on average, in funnier ideas.”

In the study, amateur and professional improv comedians, including members of the Groundlings troupe in Los Angeles, had 15 seconds to come up with funny or boring captions for cartoons while having their brains scanned. After writing each caption, they rated how funny it was on a scale from one to four.

One cartoon showed a female relationship counsellor welcoming a married couple into her office. The caption from one of the participants read: “So this is awkward. I am the woman your husband has been cheating with. Either way it will be $200 for the marriage counselling.”

According to the researchers, the brain regions activated during the creation of jokes are rich in opioid receptors, which are part of the brain’s reward system. “In the case of humour appreciation, a surprising burst of activity in those regions may lead to the feeling of mirth,” said Amir.

While getting jokes and making jokes was associated with activity in similar brain regions, the order they happened in switched around, the scientists said. When someone got a joke, brain regions involved in making connections between ideas and concepts activated first, with reward regions lighting up second. In creating a joke, the order of activity was the other way around. The reward regions might activate first in anticipation of a funny idea, but the activity could also help to generate humour, the scientists add.

Details of the study are due to be presented at the Society for Neuroscience meeting in Washington DC on Saturday.