Featured Research

from universities, journals, and other organizations

How similar are the gestures of apes and human infants? More than you might suspect

Date:
June 6, 2013
Source:
Frontiers
Summary:
A new study used naturalistic video data for the first time to compare gestures in a female chimpanzee, bonobo and human infant.

Psychologists who analyzed video footage of a female chimpanzee, a female bonobo and a female human infant in a study to compare different types of gestures at comparable stages of communicative development found remarkable similarities among the three species.

Related Articles


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," said Patricia Greenfield, a Distinguished Professor of Psychology at UCLA and co-author of the study, published in the open-access journal Frontiers in Psychology.

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 behavioral effort to elicit a response. The same standard was used for all three species. For all three, gestures were usually accompanied by one or more behavioral signs of an intention to communicate.

Charles Darwin showed in his 1872 book "The Expression of the Emotions in Man and Animals" that the same facial expressions and basic gestures occur in human populations worldwide, implying that these traits are innate. Greenfield and her colleagues have taken Darwin's conclusions a step further, providing new evidence that the origins of language can be found in gestures and new insights into the co-evolution of gestures and speech.

The apes included in the study were named Panpanzee, a female chimpanzee (Pan troglodytes), and Panbanisha, a female bonobo (Pan paniscus). They were raised together at the Language Research Center in Atlanta, which is co-directed by Sue Savage-Rumbaugh, a co-author of the study. There, the apes learned to communicate with caregivers using gestures, vocalizations and visual symbols (mainly geometric shapes) called lexigrams.

"Lexigrams were learned, as human language is, during meaningful social interactions, not from behavioral training," said the study's lead author, Kristen Gillespie-Lynch, an Assistant Professor of Psychology at the City University of New York and a former UCLA graduate student in Greenfield's laboratory.

The human girl grew up in her parents' home, along with her older brother. Where the apes' symbols were visual, the girl's symbols took the form of spoken words. Video analysis for her began at 11 months of age and continued until she was 18 months old; video analysis for the two apes began at 12 months of age and continued until they were 26 months old. An hour of video was analyzed each month for the girl, the chimpanzee and the bonobo.

Overall, the findings support the "gestures first" theory of the evolution of language. During the first half of the study, communicating with gestures was dominant in all three species. During the second half, all three species increased their symbol production -- words for the child and lexigrams for the apes.

"Gesture appeared to help all three species develop symbolic skills when they were raised in environments rich in language and communication," said Gillespie-Lynch, who conducted the research while she was at UCLA. This pattern, she said, suggests that gesture plays a role in the evolution, as well as the development, of language.

At the beginning stage of communication development, gesture was the primary mode of communication for human infant, baby chimpanzee and baby bonobo. The child progressed much more rapidly in the development of symbols. Words began to dominate her communication in the second half of the study, while the two apes continued to rely predominantly on gesture.

"This was the first indication of a distinctive human pathway to language," Greenfield said.

All three species increased their use of symbols, as opposed to gestures, as they grew older, but this change was far more pronounced for the human child. The child's transition from gesture to symbol could be a developmental model of the evolutionary pathway to human language and thus evidence for the "gestural origins of human language," Greenfield said.

While gesture may be the first step in language evolution, the psychologists also found evidence that the evolutionary pathway from gesture to human language included the "co-evolution of gestural and vocal communication." Most of the child's gestures were accompanied by vocalization (non-language sounds); the apes' gestures rarely were.

"This finding suggests that the ability to combine gesture and vocalization may have been important for the evolution of language," Greenfield said.

The researchers conclude that humans inherited a language of gestures and a latent capacity for learning symbolic language from the last ancestor we share with our chimpanzee and bonobo relatives -- an ancestor that lived approximately 6 million years ago.

The evolution of human language built on capacities that were already present in the common ancestor of the three species, the psychologists report.

"Our cross-species comparison provides insights into the communicative potential of our common ancestor," Gillespie-Lynch said.


Story Source:

The above story is based on materials provided by Frontiers. Note: Materials may be edited for content and length.


Journal Reference:

  1. K. Gillespie-Lynch, P. M. Greenfield, Y. Feng, S. Savage-Rumbaugh, H. Lyn. A Cross-Species Study of Gesture and Its Role in Symbolic Development: Implications for the Gestural Theory of Language Evolution. Frontiers in Psychology, 2013; 4 DOI: 10.3389/fpsyg.2013.00160

Cite This Page:

Frontiers. "How similar are the gestures of apes and human infants? More than you might suspect." ScienceDaily. ScienceDaily, 6 June 2013. <www.sciencedaily.com/releases/2013/06/130606190819.htm>.
Frontiers. (2013, June 6). How similar are the gestures of apes and human infants? More than you might suspect. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2013/06/130606190819.htm
Frontiers. "How similar are the gestures of apes and human infants? More than you might suspect." ScienceDaily. www.sciencedaily.com/releases/2013/06/130606190819.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Mind & Brain News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. Video provided by Newsy
Powered by NewsLook.com
Winter Can Cause Depression — Here's How To Combat It

Winter Can Cause Depression — Here's How To Combat It

Newsy (Nov. 23, 2014) — Millions of American suffer from seasonal depression every year. It can lead to adverse health effects, but there are ways to ease symptoms. Video provided by Newsy
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Milestone Birthdays Can Bring Existential Crisis, Study Says

Milestone Birthdays Can Bring Existential Crisis, Study Says

Newsy (Nov. 21, 2014) — Researchers find that as people approach new decades in their lives they make bigger life decisions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins