“There is tremendous overlap in human and chimpanzee gestures,” Jensvold shared. “Many gestures that you see in chimpanzee play, such as slaps, tickles, pokes, blocks and kicks, are ones that you would see in human play. Imagine play wrestling between two humans, and you’ve imagined a scene with two chimpanzees playing.”
In terms of chimp sounds to accompany these moves, Jensvold explained that “the vocalizations were primarily food barks, laughter, and other vocalizations that augment the context.”
“Other research from our lab shows that the chimpanzees will use a mouth sound," she said, "such as a raspberry sound, to get a caregiver’s attention. Then the chimpanzees begin gesturing.”
The findings show that chimps adjust their communications based on how much the intended receiver is paying attention. If that individual is looking at the chimp, the chimp likely will vocalize and gesture. If the individual isn't looking, he or she probably soon will, due to moves like gentle poking and annoyed foot stomps designed to grab attention.
“Dr. Jensvold’s paper is a fantastic dataset from a very unique group of chimpanzees,” Catherine Hobaiter of the University of St. Andrews School of Psychology and Neuroscience told Discovery News. “It is the first time that the natural gestures that all apes share have been researched in cross-fostered apes (meaning raised in a human environment) who also employ ASL signs.”
Hobaiter added, “Given their unusual rearing history, it’s really very interesting to see that much of their naturalistic gesturing follows similar patterns to those that we see working in the wild with free-living chimpanzees.”
Hobaiter theorizes that some long gesture sequences evolved in chimpanzees to help regulate play. “For example,” she said, “they may want to speed it up, slow it down or start to wrestle or chase.”