Vilayanur S. Ramachandran in the context of "Mirror therapy"

Nervous laughter is laughter provoked from an audience's expression of alarm, embarrassment, discomfort or confusion, rather than amusement. Nervous laughter is usually less robust in expression than "a good belly laugh", and may be combined with confused glances or awkward silence on the part of others in the audience. Nervous laughter is considered analogous to a courtesy laugh, which may be rendered by more of a conscious effort in an attempt to move a situation along more quickly, especially when the comedian is pausing for laughter.

Nervous laughter is a physical reaction to stress, tension, confusion, or anxiety. Neuroscientist Vilayanur S. Ramachandran states "We have nervous laughter because we want to make ourselves think what horrible thing we encountered isn't really as horrible as it appears, something we want to believe." Psychologist and neuroscientist Robert Provine, from the University of Maryland, studied over 1,200 "laughter episodes" and determined that 80% of laughter isn't a response to an intentional joke.