A new study conducted on Koko the gorilla, who’s been communicating via sign language for years, found that she has more command of her vocal chords than previously thought.
Ever since the 1940s, when a couple attempting to raise a pair of chimpanzees like children failed to impart the ability of speech, scientists have assumed language to be a uniquely human evolutionary adaptation.
The thinking went that apes have little to no control over vocalizations and breathing-related behaviors. What sounds they do make, researchers posited, are largely involuntary — a reflexive reaction to their environment.
But a new study by Marcus Perlman, now a postdoctoral researcher at the University of Wisconsin, suggests apes aren’t as far removed from the ability to speak as scientists think.
For several years, Perlman studied at the Gorilla Foundation in California. Much of his time was spent observing Koko, the 40-year-old gorilla who famously learned sign language and has spent her life interacting with humans.
While working at the foundation, Perlman noticed Koko seemed to have more control over her breathing and vocal chords than one would expect.
In reviewing hours and hours of footage of Koko’s vocalizations and sociable behaviors, Perlman and his research partner Nathaniel Clark, of the University of California, Santa Cruz, identified nine different, voluntary behaviors requiring Koko to exercise control over her vocalization and breathing.
When Koko wants a treat, she blows into her hand. She can also blow her nose and play wind instruments. When Koko wants a clean glass, she breathes heavily on the crystal before wiping it off. And, rather playfully, she sometimes makes a series of unintelligible grunts while pretending to talk on a toy phone.