The psychological studies about laughter have become one of important trends in emotional psychology. Major previous studies and theories are reviewed about the positive effects and the cognitive mechanisms of the laughter. Several limitations of the previous studies and some thinking points were discussed. As future directions of the laughter study, more elaborated topics are suggested including AI based emotional detection. 

Laughter is one of unique characteristics of human emotional and nonverbal social interactions. Psychologists, neuroscientists, and more recently engineers and computer scientists have been investigating the effects of humor and its corresponding response of laughter for over 30 years. Generally, laughter has been proven to affect human social functions, health, and psychological wellbeing in a positive way. Several theories on how humor and laughter have been elicited psychologically have been proposed, and tried to apply the findings to the daily life and industrial realms. This short review is conducted to introduce the main studies on the positive effects of laughter and its explaining theories. Subsequently, some significant limitations of previous studies were discussed and we suggest on how the limitations can be substantially overcome. Laughter means the joy and smiling face that comes from certain words or funny behaviors. Laughter usually comes from comic, satire, and humor. Comic is usually the story that is against the schema or a common concept. In contrast, the satire is related with interpersonal interactions in which the words pick out weakpoints or mistakes of people. Finally, humor comes from compassion and attention toward a person or a context rather than the critical aspects. Humor is rather complex concept and described in details in the following sections. Recently, the major impetus for the popularity of laughter’s encouragement in developing countries is due to various laughter training programs. The laughter training programs perform several sessions of educations and training to general public. The common part of the training programs is conducting an intentional laughing in which the attendees smile with loud sound and prolonged durations. The following question is then on what mechanisms this kind of laughing could affect us positively, eventually improving our psychological wellbeing. At the same time, it is a question on what types of laughing would be more effective, and the previous studies did not deal with this question sufficiently.

As measuring emotional expression including laughter has been developing, the AI based technology on laughter can be applied in our daily life. One area of main interest is making a robot system which can perceive human laughter and possibly express laughter itself. For example, the robot system can analyze the human facial movement and determine which basic emotion the human is expressing. And then the robot can produce an appropriate response (verbal or action) to communicate with the human. If the robot laughs with facial expression or with an appropriate sound, then the emotional common ground can be formed between the robot and the human so that the possible loneliness of human can be reduced up to certain degrees. It has been proven that the robot with emotional communication capability is much more suitable for the family robot than the one without. IOT based system can be also beneficial to human in the sense that the IOT can detect human emotional state. For example, the audio system IOT can be matched with human emotional state and suggests appropriate music types to elevate the joy or reduce the sadness Similarly, if it is the theater system, it can suggest a movie or a drama that match with human’s ongoing emotional state. A leading emotional detection company, the Affectivia, has developed the smart phone-based face recognition system. It measures the various movement of human face muscle, and can tell the basic emotion such as joy, sadness, surprise, disgusting, and so on. This kind of technology, however, only catch temporary emotion so that the long-term monitoring of the emotion is not possible. Furthermore, the privacy of a user can be violated.

With Regards,
Joseph Kent
Journal Manager
Journal of Brain Behaviour & Cognitive Sciences