In this hypothesis paper, I propose a three-component set of jointly necessary and sufficient trigger criteria for all cases of involuntary laughter. The theory incorporates concepts from the theory of mind in cognitive science. I then examine the information content of the laughter signal from a game theoretic perspective. I conclude that laughter is a signal of cooperator value as it provides information on the laugher's empathy with the attributed mental states and her sympathy levels for all affected by the laugh-inducing situation. Laughter also indicates what types of mental representations children, autistic people, nonhuman primates and adults possess and can falsify.