"A day without laughter is a day wasted," said the comedian Charlie Chaplin and scientists are starting to agree. Every couple of months, there are news stories claiming that chuckling is good for your health and scientists are only just beginning to understand what happens in the brain when we laugh. We don't only laugh because something is funny, but also for a range of social reasons like when we feel awkward or surprised. But for most of us, laughing is a pleasurable experience and researchers are looking at the health benefits it could have.

What makes us laugh

Certain regions of the brain can cause laughter, for example the supplementary motor area which is associated with certain types of planning and motor organisation. Stimulation of this area elicits laughter and a sense of mirth. Other areas of the brain are also involved, for example people with benign brain tumours near the hypothalamus can have uncontrollable fits of laughter, called gelastic seizures.