We start finding things laughable -- or not laughable -- early in life. An infant first smiles at approximately eight days of age. In his book Beyond Laughter, psychiatrist Martin Grotjahn says that the earlier infants begin to smile and laugh, the more advanced their development is. Studies revealed   that children who did not develop these responses "developed a schizophrenic psychosis   in later life, or simply gave up and died". Between the ages of six months and one year, babies learn to laugh for essentially the same reasons why they will laugh throughout their lives, says Dr. Jacob Levine. He says that people laugh to express mastery over an anxiety. Adult laughter is more subtle  , but we also laugh at what we used to fear. The feeling of achievement, or lack of it, remains a leading factor. Giving a first dinner party is an anxious event for newly-weds. Will the food be good? Will the guests get along? All goes well; the party is over. Now they laugh freely. Their pleasure is from recalling the evening's activities. They couldn't enjoy the second pleasure without the first. Laughter is a social response caused by signals. Scientists have not determined a brain center for laughter, and they are puzzled by patients with certain types of brain damage who go into laughing with no apparent reason. The rest of us require company and a reason to laugh. Another reason why laughter is pleasurable is because of the physical feeling involved. According to Dr. Levine, we can measure our adjustment to the world by our capacity   to laugh. When we are secure about our abilities, we can make fun of our weakness. If we can laugh through our anxieties, we will not be overpowered   by them. The ability to laugh starts early, but it takes a lifetime to perfect. Says Dr. Levine, "When social relationships are mastered, when individuals have mastered... a peaceful relationship with themselves, then they have ... the sense of humor." And then they can throw back their heads and laugh. The infant who begins to smile or laugh early will   _  .
become a more subtle laughter when he or she grows up be more likely to take a whole life to perfect smiling and laughing have more advantages of development in growth and health suffer from schizophrenic psychosis and even die in later life