Apes and human infants show similar communicative gestures
Washington: Researchers have found that a female chimpanzee, a female bonobo and a female human infant showed similar gestures during the communicative development stages.
This is the first time such data have been used to compare the development of gestures across species.
The chimpanzee and bonobo, formerly called the "pygmy chimpanzee," are the two species most closely related to humans in the evolutionary tree.
"The similarity in the form and function of the gestures in a human infant, a baby chimpanzee and a baby bonobo was remarkable," Patricia Greenfield, a Distinguished Professor of Psychology at UCLA and co-author of the study, said.
Gestures made by all three species included reaching, pointing with fingers or the head, and raising the arms to ask to be picked up.
The researchers called "striking" the finding that the gestures of all three species were "predominantly communicative," Greenfield said.
To be classified as communicative, a gesture had to include eye contact with the conversational partner, be accompanied by vocalization (non-speech sounds) or include a visible behavioural effort to elicit a response.
The study is published in the open-access journal Frontiers in Psychology.