Laughter is a typically pleasant physical reaction and emotion consisting usually of rhythmical, usually audible contractions of the diaphragm and other parts of the respiratory system. It is aa response to certain external or internal stimuli. Laughter can rise from such activities as being tickled,[1] or from humorous stories, imageryvideos or thoughts.[2] Most commonly, it is considered an auditory expression of a number of positive emotional states, such as joy, mirth, happiness or relief. On some occasions, however, it may be caused by contrary emotional states such as embarrassment, surprise, or confusion such as nervous laughter or courtesy laugh. Age, gender, education, language and culture are all indicators[3] as to whether a person will experience laughter in a given situation. Other than humans, some other species