Berk was off and running and published his first findings in 1985. But some of his most important research was revealed in 2001 when he and several colleagues reported on a study of heart patients at Loma Linda University. The 48 patients were divided into two groups, one of which watched 30 minutes of comedy every day, in addition to their regular cardiac care program. The other group didn't see the movies.
The patients were followed for one year, and the results were dramatic.
"Heart attacks diminished drastically in the group that watched the comedies," Berk says. Other symptoms improved to the point that medications were reduced. Only two of the patients who watched the movies had heart attacks during the experiment, compared to 10 who did not see the movies.
"It blew my mind," Berk says.
Cousins, who had made it possible for Berk to continue his inquiries, wasn't around for the latest result. The two talked for the last time in 1990, when Berk brought Cousins up to date on his work.
"Norman died two weeks later," Berk says.
Berk and several colleagues continued the line of research, resulting in the most recent findings. They recruited 16 healthy males and divided them into two groups. Blood was drawn from all the subjects before the experiment, four times during the hour-long video, and three times afterward. Members of one group watched a funny movie of their choice, but the second group didn't get to see the film.
The results, Berk says, were dramatic.
Even before the movie began, and long after it ended, the blood chemistry in the group watching the movie changed. Beta-endorphins, the so called body's own morphine, rose by 27 percent, and human growth hormone rose by 87 percent compared to the group that didn't see the movie.
That's significant, Berk says, because of the role both those substances play.
"Endorphins are the stuff that make you feel good," he says. "It's the stuff that's related to orgasmic response. It's the runner's high."
It also slows down the heart rate, reduces blood pressure and opens air passages.
Human growth hormone "cranks up at night, when you and I are asleep," Berk says. "It's one of the hormones that helps re-tune a lot of things. And it tunes up and optimizes the immune system."
Thus, his findings indicate there is a physiological basis for the good things that come from laughing. Small studies, to be sure, and much more research needs to be done, but funding will continue to be tight.
That's partly because you can't put laughter in a bottle, patent it and sell it for a profit. It's enough to make you cry.