Sense Of "Self" And Ability To Play May Depend More On Social Background, According To New Study With Chimpanzees

April 07, 1997

WRITER: Phil Williams, 706/542-8501,

ATHENS, Ga. -- A sense of "self" and the enjoyment of play may have more to do with rearing history than was previously thought, according to a new study by a graduate student at the University of Georgia.

In studies with the noted chimpanzee Washoe and others like her reared in a human environment, the researchers found that the capacity for self-knowledge may exist before it is ever expressed. The study was apparently the first ever to examine the reaction of chimps to their own images in hand-held mirrors.

"As an anthropologist, I tie all of this back to human evolutionary history," said Warren Roberts, a doctoral student. "With these special chimps, we can see the kinds of behaviors we don't see in feral populations and which may help us understand the evolution of culture. One might conclude that culture doesn't evolve purely from the human brain."

Roberts presented his research on April 3 at the annual meeting of the Association for the Study of Play and the Society for Research in Child Development in Washington, D.C.

Washoe and fellow chimps Moja, Tatu, Dar and Loulis are among the most-studied apes on Earth. They live in a compound at Central Washington University of Ellensburg, WA, where they interact on a daily basis with a staff that includes noted primatologist Roger Fouts. Washoe in particular has been the subject of several television documentaries, showing how she can use sign language to communicate, a skill now shared by the other chimps at CWU.

A number of researchers have worked with the colony to try and understand cognition -- how animals and humans learn. Roberts, along with colleague Mark Krause at the University of Tennessee in Knoxville, wanted to see how the chimps reacted to the presence of hand-held mirrors and how their reactions related to their sense of self and their enjoyment of play.

"I was looking at them from an anthropological perspective, and so it was different from what experimental psychologists do," said Roberts, who received a scholarship from the lab for the eight-month study. "We have a funny notion that animals have a typical behavior for their species in nature. But with such complex animals as apes, rearing history means they don't always mature into that type-form. This calls into question both `human nature' and animal nature'."

The idea was quite simple: Provide the chimps with numerous articles of clothing and accessories and give them hand-held mirrors to see if their self-image changed depending on what they saw. Roberts, who had been studying ape language since 1991, already had considerable experience in primate cognition and was able to communicate with the chimps through sign language as well.

At first, the chimps reacted to his presence by asking him for get "forbidden" items outside their living areas or by simply telling him to get them food. Soon, however, they became accustomed to him, and he was able to watch them as they played and looked at themselves in the mirrors.

In years past, studies on self-recognition among chimpanzees was done by anesthetizing them and putting a red dot on their foreheads as they slept. When they awoke, they were shown their images in mirrors and observed as they dealt with the change in their appearance. Roberts, however, felt that simple, day-by-day observation might reveal as much about chimps and help eliminate some problems associated with the dot test.

"What we found is that the modifications they made in their appearance is not random," said Roberts. "In fact, they took an amazing amount of time in putting on clothes and jewelry. If you gave my eight-month-old daughter lipstick, God knows where it would end up. With these chimps, it wound up on their lips."

The chimps appeared to act very much like young children, making faces in their small mirrors and checking out how a new hat or barrette looked. The chimps were not handed the mirrors but instead chose to use them when they found them in their cages. Roberts noted that the rearing history of the chimps was crucial in understanding their behavior, since they had been around humans their whole lives. And he said that such tests could not be repeated in most labs where chimps have been reared with less human contact.

Still, Roberts concluded from the observational study that the capacity in the brain for playful self-expression was around long before the capacity to express it. He said that chimps do play this way in the wild "but it is not as richly symbolic as this." He referred to the behavior of the chimps at CWU as "guided re-invention."

Working with the chimps daily gave Roberts an insight into just how intelligent they are and how quickly they make associations. One day, he came to their living area wearing a pair of very dark sunglasses, and the chimp Moja studied him for a while and then made the sign for "cat mask." After that, whenever Moja saw Roberts, the chimp would refer to him as "cat mask."

"I was honestly blown away by everything I saw during my time there," said Roberts. "To see these animals putting on lip gloss using a mirror to guide their hands was an amazing thing."

Roberts does not expect his study to resolve the many questions surrounding animal communication that have arisen from earlier work with Washoe and friends. And he knows that issues of self-recognition will remain difficult to examine with chimps.

"We know our data won't resolve the conflict over cognition in chimpanzees," he said, "but our work does show a different level of activity with mirrors than has ever been seen before. I think this kind of observational work is a perfectly legitimate way to study the problem."

(Writers: Warren Roberts may be contacted through the department of anthropology at the University of Georgia. Please call 706/542-3922 and leave a message for him.)

University of Georgia

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