The researchers said they scanned the brains of 22 males and females between the ages of 6 and 13 while the study subjects viewed humorous videos, such as people falling down and animals performing tricks, the Daily Mail reported Friday.
The subjects were also shown "positive" clips, such as dancers and snowboarders, and "neutral" clips of nature and children riding bikes.
MRI scanning of the children's brains discovered the girls' brains showed more heightened activity during the humorous videos, indicating they were feeling stronger mirth and positive feelings than the boys.
"Our data for the first time disclose that sex differences in humor appreciation already exist in young children," the researchers wrote.
The researchers said their findings suggest women are genetically predisposed to prefer men who can make them laugh "because the female brain, and particularly the reward circuit, is biologically better prepared to respond accordingly."
The study is published in the journal Social Neuroscience.