What is laughter?

A person might ask: what is laughter?  How does it work?  My last post, Why do people laugh?, describes the different types of laughter and what triggers them.  There still might be lingering questions about the anatomy of laughter, curiosity that I strive to quench.  Why is it so easy to detect when laughter is feigned?  And, why does it seem impossible to stifle laughter when you find something amusing?

Firstly, laughter is the physiological response to humor.  It's the body's way of coping with an intense flood of emotions.  Sometimes there isn't even a real explanation.  Nevertheless, some aspects of it can be explained scientifically.

The lungs are the larynx are the mechanisms used when coughing or speaking.  They also create the sound of our laugh.  Normally, air passes freely through our open vocal cords in the larynx.  When they close, air cannot pass through them and when they're partially open, some sort of sound is generated.  Laughter is the result when we exhale through closed or partially open vocal cords.  The respiratory muscles periodically activate to produce the characteristic sound of laughter.

Why is it so difficult to fake laughter?  It seems as if feigned laughter stands out clearly and makes an awkward situation even more awkward.  This is because, besides the fact that laughing can sometimes be completely involuntary, it involves the movement of a complex series of muscles to produce a proper, genuine laugh.  A simulated one, however, doesn't quite sound the same, in part because the same muscles are not being triggered.  It requires an active effort to feign laughter.  Furthermore, the risorius muscle and the zygomaticus muscle are both used in smiling and, therefore, laughing.  Since the risorius muscle affects a smaller portion of the face than the zygomaticus muscle, it is easier to control and is therefore commonly used to feign amusement, hence why fake laughter is easy to detect.

Similarly, it is so hard to suppress laughter for this reason; laughter is often involuntary and involves the moving of a complex series of muscles.  Laughter may seem uncontrollable at times.  Particularly laughter caused from amusement.

The study of laughter and its effects on the human body, both psychologically and physiologically, is called gelotology.  Sometimes it's useful, and sometimes it's just fun.  Or perhaps, ironically, funny.