Laughter in Chimpanzees and Humans - Biology 342 Fall 2012
By Yuan Xue, Soso
Laughter is Not An Exclusive Behavior to Humans
Since the time of Darwin, it has been found that human is not the only primate that performs “laughter”; Common Chimpanzees (Pan troglodytes) have been one of the most extensively studied non-human primates for their laughter-like behavior. Chimpanzees have been found to communicate and bond with other members of a community through use of laughter-like behavior. Many studies have been conducted to investigate the relations between human laughter and Chimpanzee laughter-like behaviors in terms of mechanical similarities and differences. On this website, we will take a look at how chimpanzee produces its “laughter” and compares it to human's laughter production; we will also take a look at the role that laughter plays throughout development of both human and chimpanzee infants; we will compare the evolutionary changes in primates that made chimpanzees and humans laugh possible, and give explanations for the differences that we observe in the laughing patterns between the two primate species; finally, we will attempt to explain the benefits of laughter behavior that conserved it ubiquity among primate species as communication signal.
Try to listen to the following two sound clips:
A chimpanzee's laughter-like sound
A human toddler's laughter
Notice that chimpanzee produces a “pant-pant” sound that lacks discrete, vowel-like notes that have sharp leading and trailing edges on sound spectra. This is because chimpanzee's laughter is a breathy panting vocalization that is produced during each brief expiration and inspiration, unlike in human’s laughter where the vowel-like notes are produce by chopping a single expiration, producing a speech-laugh pattern that sounds like "haaa-haaa-haaa".