Great apes deploy more than 80 signals to communicate everyday goals, according to a new study.
People frequently use gestures to accompany and develop language, from gesturing to nodding and dynamic arm movements. It has recently been hypothesized that humans may also comprehend the sign language employed by apes, suggesting that humans may still have inherited from their forebears a comprehension of ape communication.
According to a study published on Tuesday in the journal PLOS Biology, great apes use more than 80 signals to communicate their daily objectives. The “huge loud scratch,” which signifies “groom me,” is one of these signals. Apes use it to brush dirt or insects out of one other’s hair. “Object shake” can be interpreted as “move away,” “let’s have sex,” or “groom me.”
For bonobos, the “directed push” signifies “get on my back,” but for chimpanzees, it indicates “move to a new posture.” The study found that bonobos and chimpanzees are the closest living cousins of humans, sharing more than 90% of our motions.
According to the study’s authors, primatologist Catherine Hobaiter, a principal investigator at the university’s Wild Minds Lab, and research scholar Kirsty E. Graham of the University of St. Andrews in Scotland, these gestures may have played a significant role in the development of human language.
More than 50 ape movements have been observed in infants between the ages of one and two, according to researchers. Therefore, it was assumed that humans may have kept their memory of the fundamental components of ape motions.
How does it function?
Researchers used data from 5,656 viewers of 20 web movies that were edited to display a bonobo or chimpanzee gesture but not the reaction it elicited.
To include in the movies, the researchers choose 10 of the most prevalent gesture forms that had previously been discovered to convey meaning to both chimpanzees and bonobos.
To make it easier for untrained viewers to recognize the motion in the clips, they were each accompanied by a brief illustration of the gesture.
A “video only” game or movie with one line of context explaining what the apes were doing prior to making a gesture was randomly assigned to each participant.
This type of understanding study has been used to evaluate the language comprehension of nonhuman creatures, but this time the model was reversed.
The participants were found to be able to effectively understand the chimpanzee and bonobo movements with slightly over 50% accuracy, which is double what is expected by chance, Graham wrote to CNN via email on Thursday.
Some motions, such as the “mouth stroke” (which means “give me that food”) and the “great loud scratch,” had success rates of up to 80%.
Intelligent or biological?
The researchers emphasized that the underlying process through which humans can understand apes is still a mystery.
Some possibilities for this conundrum include the biological inheritance of the great ape repertoire, the similarity between gestures and the activities they are intended to elicit, and the fact that humans and apes share body plans and social purposes.
We need to look at how people interpreted the gestures do people have a vocabulary or capacity that they inherit, or do we have to think our way through it? It’s a major subject that will need to be addressed in many different ways, Graham added.