Research into laughter is dwarfed by the scale of work into emotions such as fear and disgust, however it is probably one of the most frequently encountered emotional expressions. In this talk I will outline the physical bases of laughter, and aspects of its evolution. I will describe the disparities between people’s lay understanding of when we laugh, which tend to be focussed on humour with studies which reveal the social foundations of laughter. I will address the neural basis of the perception of laughter and discuss how these studies may relevant to the roles of laughter in interactions.