According to ABC news, the pressure is the cause of the decline of memory, while laughter can ease the pressure. In this regard, California scientists Loma Linda university to do an experiment: they asked 20 healthy adults as a group, watch a funny video is 20 minutes long a time. And another group of adults were asked to sit quietly, and don't watch any video. Then, the two groups of the pressure test, content and take their saliva sample to analysis the stress hormone cortisol. The results show that, to watch a funny video than people without watching people performed better in a memory test. Moreover, due to watch a funny video in which has been in a state of laughter, content of the stress hormone cortisol in saliva and their much lower.
Study author Gurinder Bains said in an interview with ABC news: "as we age, learning ability and delayed recall to us will be much more challenging. And friends laugh together, watching interesting TV program for a short, these seemingly simple things will help us to relieve stress in daily life. Therefore, the normal pressure is very small people tend to have good memory." The researchers also explained that this is because the smile will make the endorphin content of human body, and can transport a chemical called dopamine into the brain, providing a kind of happy feeling for the human body. This change in brain waves will make the human memory level has improved.