David Huron
Department of Speech, Music and Hearing
Swedish Royal Institute of Technology (KTH), September 28, 2005
While most laughter involves some language-based humor, laughter can also be evoked by stimuli without language. In the music of Peter Schickele (alias "P.D.Q. Bach"), for example, simple sequences of pitches can cause listeners to burst out laughing. Why? Sixty-four live recordings of Schickele's music were analyzed and 629 moments of audience laughter were identified. Each moment was classified according to the probable cause of the laughter. Excluding language-based humor and visual gags, all of the identifiable moments of laughter appear to be traceable to marked violates of expectation. An information theoretic analysis suggests that laughter is most likely to occur when there is greater than a 100-fold difference in probability between the expected and actual outcomes.
Existing research on musically-induced frisson ("shivers") also implicates violations of expectation. Similarly, musically-induced awe (gasping or breath-holding) is also linked to surprise. A unified evolutionary account is proposed that attempts to explain how surprise leads to either frisson, laughter, or awe. The physiological responses are shown to resemble fight, flight, and freeze.