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Not a Foreign Language: How Apes Communicate with Each Other

Katja Liebal Is a Newly Appointed Junior Professor at the Institute of Psychology at Freie Universität Berlin

Jan 08, 2010

Der Schein trügt: Affen sind keine Schmusetiere. Katja Liebal transportiert einen Affen ins Gehege.
Appearances can be deceptive: Apes are not cuddly animals. Katja Liebal is shown carrying an ape into the enclosure. Image Credit: Katie Slocombe

What makes us human? Newly appointed junior professor Katja Liebal is examining this far-reaching question in her new workplace: The 33-year-old Liebal has been conducting research at the Institute of Psychology and the “Languages of Emotion” cluster of excellence at Freie Universität Berlin since the summer semester, observing how great apes make contact with each other and convey information using gestures. Her findings: The boundary between humans and apes is more fluid than previously thought.

Earlier, scientists presumed that only humans were capable of learning complex languages. But then more recent research showed that apes are also able to exchange basic information using a system of symbols – and that while they cannot use the spoken word as a medium, they can indeed communicate through signs and gestures. This enables these animals to carry out simple communicative actions.

During her studies, when she observed apes in captivity and in the wild, Liebal focused on these forms of communication. She asked what hand movements great apes have to practice and which body positions and facial expressions they use in order to initiate contact with each other.

“Getting to the point of being able to see the communicative functions that the individual gestures have is a very long process. It takes at least 100 hours of observation before you can understand what is really taking place between the apes,” the scientist says. After this intensive period of orientation and familiarization, however, people can see that apes utilize their gestures within the group deliberately in order to affect the behavior of other animals. The range of gestures used is very broad, spanning from invitations to play to expressions of anger and frustration. “But what is especially surprising is their flexibility: Apes can invent new gestures. Then they incorporate them into the repertoire used by their group. Plus, the majority of the gestures are not specifically tied to a single context. Instead, their meanings are variable and depend on the context.”

Looking for a Shared Language

In her research, Liebal works based on a comparative approach rooted in developmental psychology. She originally studied biology at the University of Leipzig, where she earned her Diplom degree in 2001. After that, she moved to the Max Planck Institute for Evolutionary Anthropology (Department of Comparative and Developmental Psychology), where she earned her doctorate in 2005. That same year, Liebal moved to England to teach in the Department of Psychology at the University of Portsmouth.

Now at Freie Universität Berlin, Liebal has been working within the “Languages of Emotion” cluster of excellence since the summer semester of 2009, a position she perceives as a great challenge. “On a thematic level, I am much better situated here in Berlin than I was in England. Within the cluster, many different disciplines are in contact with each other. It is very exciting to work with ethnologists, literature specialists, sociologists, and other scientists and academics from different disciplines and find a common language.” In the future, Liebal plans to work even more intensively with comparative approaches, with the aim of finding out when facial expressions in the great apes are expressions of emotions and in what form their gestures are different from those of humans.

Further Information

Prof. Dr. Katja Liebal, Languages of Emotion Cluster of Excellence, Freie Universität Berlin
Tel.: +49 (0)30 838 57846; Email: liebal(at)