From those first baby giggles, we begin to use laughter. It can be used to make us popular and it can be used as an emotional release mechanism. Whilst we are born with the physical ability to laugh, the capacity to utilise it as a social tool is something we learn. And in order to do this, we need to develop a sense of humour. Stephanie Davies is one of the country's preeminent laughter experts. A former stand-up comedian, she studied the science...