Activity in the brains of 13 people exposed to humour in four different tests was monitored using fMRI.
The discovery may provide ammunition in arguments between the sexes in every living room and pub across the UK, but it could also help doctors treating stroke victims.
A second study has also found the brain's "funny bone" - it determines whether or not you have a sense of humour.
Listening skills
A listening study of 20 men and 20 women found men use the left side of the brain - traditionally associated with understanding language - to pick up conversations. But women also used the right side.
Dr Joseph T Lurito, assistant radiology professor at Indiana University School of Medicine, said: "I don't want to provoke a battle of the sexes. I just want people to realise that men and women may process language differently."
Presenting evidence at the Radiological Society of North America's annual meeting, he suggested women were not necessarily better listeners.
He said women may need to use more of their brain to listen to conversations, but said it could show women could listen to two conversations at once.
The study used functional magnetic resonance imaging (fMRI) to measure brain activity by producing multi-dimensional images of blood flow to various parts of the brain.
Participants listened to excerpts from John Grisham's novel The Partner, while researchers monitored reactions.
Mood disorders
Researchers may also have identified the part of the brain that identifies a joke.
Dean Shibata, of the University of Rochester Medical School, told the Radiology Society conference that a small part of the frontal lobe appeared to be critical to finding a joke funny.
Activity in the brains of 13 people exposed to humour in four different tests was monitored using fMRI.
Mr Shibata said: "In the future, scans of the brain might be used routinely by psychiatrists to assess patients who have mood disorders such as depression, which often is accompanied by a loss of humour."
The study could also help to explain why strokes which affect the lower frontal lobes of the brain can lead to a personality change, including the loss of a sense of humour.
Treatment hope
Dr Veena Kumari, a senior psychologist at the Institute of Psychiatry in London, said the research would help to establish the cause of problems within the brain, which could then lead to treatment.
"It could be altered by altering the receptor functions and it could be treated by certain drugs."
She added she was not surprised women used both sides of their brain to listen.
"They use both parts of their brain more often for many things. Men have very clearly defined functions."