Since the publication of Freud's study, psychologists have continued to explore humour and jokes in their quest to explain, predict and control an individual's "sense of humour". Why do people laugh? Why do people find something funny? Can jokes predict character, or vice versa, can character predict the jokes an individual laughs at? What is a "sense of humour"? A current review of the popular magazine "Psychology Today" lists over 200 articles discussing various aspects of humour; in psychological jargon the subject area has become both an emotion to measure and a tool to use in diagnostics and treatment. A new psychological assessment tool, the Values in Action Inventory developed by the American psychologists Christopher Peterson and Martin Seligman includes humour (and playfulness) as one of the core character strengths of an individual. As such, it could be a good predictor of life satisfaction. For psychologists, it would be useful to measure both how much of this strength an individual has and how it can be measurably increased.