You may have already heard the sentence: “Children laugh much more often than adults do.” This is what actually many people think. From a scientific point of view, this question has not been answered sufficiently. But first, let’s go back to the basics: Why do we laugh?
Laughter is a physical reaction to a certain stimulus that can be of physical nature, like tickling,  or of purely emotional nature,  like laughing at a very funy joke. In any case, it is considered to be a very primitive vocalization that even very young babys of several weeks are able to accomplish in their still pretty limited set of facial expressions.
Then again, is it only a question of age, or is it also gender and/or character-dependent? Social interactions seem to play an important role for how much a person is laughing per hour or per day. But how do you really quantify laughter? Isn’t that the biggest problem? According to Rod A. Martin, professor for Clinical Psychology at the University of Western Ontario deals scientifically with these sorts of questions and isn’t so sure about children laughing much more often than adults being actually true.  According to his studies and a quick survey of the scientific landscape leads him to think that even the opposite might be true. But then again, is it really that important? Prof. Martin puts it quite nicely when he concludes his article saying: ” […] this is certainly one of those areas in which “further research is needed.””
 Stearns, Frederic Rudolph (1972). Laughing: Physiology, Pathology, Psychology, Pathopsychology and Development. pp. 59–65. ISBN 0398024200.
 Shultz, T. R., & Horibe, F. (1974). Development of the appreciation of verbal jokes. Developmental Psychology, 10, 13-20.
 http://www.aath.org/do-children-laugh-much-more-often-than-adults-do (11.11.14)