A 2007 survey of existing tools to measure humour identified more than 60 psychological measurement instruments. These measurement tools use many different approaches to quantify humour along with its related states and traits. There are tools to measure an individual's physical response by their smile; the Facial Action Coding System (FACS) is one of several tools used to identify any one of multiple types of smiles. Or the laugh can be measured to calculate the funniness response of an individual; multiple types of laughter have been identified. It must be stressed here that both smiles and laughter are not always a response to something funny. In trying to develop a measurement tool, most systems use "jokes and cartoons" as their test materials. However, because no two tools use the same jokes, and across languages this would not be feasible, how does one determine that the assessment objects are comparable? Moving on, whom does one ask to rate the sense of humour of an individual? Does one ask the person themselves, an impartial observer, or their family, friends and colleagues? Furthermore, has the current mood of the test subjects been considered; someone with a recent death in the family might not be much prone to laughter. Given the plethora of variants revealed by even a superficial glance at the problem, it becomes evident that these paths of scientific inquiry are mined with problematic pitfalls and questionable solutions.