Science has shown that laughing for ten minutes will increase blood flow, use 80 muscles, and burn up to 40 calories. Since laughing uses so many different muscles and gets the heart pumping, it is basically a mild aerobic workout.
Results of a study, done with lab rats, showed that increased blood flow brought about by aerobic exercise will promote the growth of the body’s neuronal infrastructure. This is further supported by a team of researchers at Duke University whose study says that aerobic exercise improves the cognitive functions of older men and women.
Therefore, I hypothesize that laughing can enhance the learning process because of the improved flow of oxygen-rich blood, and possibly endorphins, to the brain.
Here is a link to a great article on laughing: The Funny Thing About Laughter.