In the current experiment, Berk and his colleagues studied 16 healthy and fasting males, who hadn't exercised for at least a day and were not taking supplement medications. The test subjects had chosen a favorite video. Three days before the experiment, all the subjects were told which group they were randomly selected to be in, experimental (video watching) or control (no video watching). All subjects had blood drawn just before the video watching experiment began (baseline), four times during the hour-long experiment, and three times afterward.
"One of the keys in this kind of experiment is to set the baseline and control environment carefully," Berk said. "In this case, the control group basically sits in a 'neutral' room waiting to have their blood drawn, and on the tables there is a wide variety of magazines that they can browse, because you don't want to bias what they do or watch. Time and behavior have proved me right with this approach," he added.
Earlier experiments showed stress reduction
Berk said the results of this "anticipatory mirthful laughter experience, which is a kind of eustress or 'positive/good stress' event, builds on our earlier work and may constitute a real construct for what is the 'biology of hope.'" Earlier experiments showed that viewing a favorite funny video can offset symptoms of chronic stress, which can suppress various components of the immune responses, particularly those related to anti-viral and anti-tumor defenses. In addition, there appears to be a rebalancing of the Th1/Th2 immune response which suggestively could lead to reduction of autoimmune issues.