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Eye on Psi Chi: Fall 2013

Eye on Psi Chi

Fall 2013 | Volume 18 | Issue 1

Apes and Their Future in Comparative Research: A Conversation With Dr. Duane Rumbaugh

Dava Stewart

View this issue in Digital and PDF formats.

Since the advent of comparative psychology, scientists have tried to avoid anthropomorphising, or humanizing, their animal subjects. Attributing human characteristics to animals is easy to do; most pet owners will say that their pets understand at least some human language, for example. When Dr. Duane Rumbaugh and his team began their work with nonhuman primates and language, they began with no assumptions—not even that the apes could acquire language. They were determined to gather evidence based on solid research methods on what dimensions of language an ape might learn and the conditions under which they had been learned. Given the ape’s relatively small brain (compared to ours), the researchers’ optimism was not high.

The Beginning: Lana

Although his career did not all begin with Lana, Dr. Rumbaugh describes her as "the grandmother of all my professional life” (2013). Lana is a chimpanzee who learned the word-symbols and grammar of Yerkish, a language that Dr. Rumbaugh and his colleagues created at the Yerkes Regional Primate Center. The language consisted of symbols, called lexigrams, on a computerized keyboard. Each lexigram represented a word, and to ensure that Lana understood the meanings of the lexigrams rather than simply memorizing their locations, they were moved around on the keyboard. Lana’s achievements still inspire researchers. In fact, Lana still participates in research.

A chimpanzee that could communicate with humans made headlines in 1975. Unfortunately, those headlines focused on the wrong thing. "The emphasis on Yerkish was predictable,” says Dr. Rumbaugh. "We just didn’t predict it. They [reporters] made it seem as if we created a language that made us magically able to communicate with the apes. The lexigrams were important because they had to be discernable and had to fit on the keys, but at the same time they were but tools for our research. The more important part of the whole thing was the question ‘Can an ape really learn what the symbols mean?’”

The answer to that question is the result of some creative genius on the part of the researchers. Dr. Rumbaugh first linked sets of the lexigrams together, so that if any one symbol in a set was pressed, the entire set would activate. For example, if any of the keys in the set that represented asking for milk were pressed, Lana would be given milk. Eventually, the keys were separated, so that Lana would have to search for and press each lexigram in the request in order to receive milk.

Even now, more than 30 years later, Lana’s accomplishments seem utterly fantastic. As the Yerkes Center director at the time pointed out, "There’s just something mystical about apes, language, and computers.” Lana learned to clearly communicate her wants, needs, and preferences using the keyboard. More than that, she applied what she learned in unexpected ways—to make requests that researchers never taught her and thereby solve novel problem that she faced.

The idea that complex learning occurs through a series of amalgams rather than by responses to individual stimuli permeates Dr. Rumbaugh’s work. He strongly opposes the ideas that animals are simply empty beings with no psyche, or capability to feel emotion, perceive pain, or otherwise experience the world as humans do. Careful, varied research over the course of his career has shown "all of the different kinds of responses are important to gel into a larger picture. Apes are surprisingly competent at doing that—much more than we thought 50 years ago. Animals were thought to be unintelligent and empty, but the brain is hungry for stimulation, for experiences of the live-a-day world as information within which it searches for forms patterns and systems of "knowing”. That is what the brain does, day and night.”

Dr. Rumbaugh described the way that many separate concepts can come together and create a whole with a story that most psychology students can relate to: "When I was in school, we called statistics class the Mystery Hour. We all understood the numerals and some of the theories, but we still couldn’t quite see our way through the fog. But we each eventually had an ‘aha!’ moment. The whole thing just congealed—and it was like a symphony, with all of the parts working together.” Dr. Rumbaugh’s work has shown that apes possess the ability to use seemingly disparate bits of knowledge to find systems and patterns in much the same manner as statistics students.

In 2007, Dr. Rumbaugh and several colleagues published A Salience Theory of Learning and Behavior—With Perspectives on Neurobiology and Cognition (Rumbaugh, King, Beran, Washburn & Gould, 2007). In it, they outlined a new theory of learning and behavior. Salience theory takes into account instinct, conditioning, and unforeseen, novel behaviors that Dr. Rumbaugh calls emergents. "My 60 years of work led me to a redefinition of how learning occurs. Reinforcement is not sufficient on its own to explain learning,” Dr. Rumbaugh says. Salience theory "has been warmly received by all but those who adhere to the ancient definition of reinforcement. Reinforcement is reformulated in terms of attributes that all stimuli have in a given stimulation. As we eat or meal or an animal learns to press a key to get food, a host of stimuli are present and are in interaction with one another. The stimulus events form amalgams in which each stimulus enters in accordance with its salience and its response eliciting properties. Amalgams are both formed and organized by the brain into networks that organize them rationally into what we might call knowledge. Hence, it is not just the strongest but all stimulus events that impact upon what is learned and usable in the future. The traditional ‘reinforcer’ is but the strongest of events in a situation.”

Lana provided an excellent example of an emergent behavior early in her work with the keyboard. It was useful for caretakers and researchers if she did not urinate any where she wished in her enclosure, so they used a conditioning technique to train her to use a pan. Each time Lana urinated in the pan, she received a reward.

Lana, however, did not just learn that she would be rewarded for urinating in the pan. Instead, she also concluded that it must be the putting liquid in the pan that resulted in a reward. When she could not no longer urinate, she would spit in the pan and then look expectantly for a reward even though that behavior had not been reinforced at any time. Dr. Rumbaugh explains, "It is the dynamic flow of contexts, stimuli, and much else—it is the integrating of all these things that allow the brain to work.”

The Language Research Center

In 1980, Georgia State University built the Language Research Center, founded by Dr. Rumbaugh, and where he served as director until 2001. He and his team, as well as researchers from around the world, carried out numerous studies on nonhuman primates. A bonobo named Kanzi taught them a great deal about comprehension. Kanzi was at the Language Research Center as an infant, but not as the subject of language training or research. An adult female named Matata acted as his mother, and he was always there with her. Matata was not a particularly good student, but, to everyone’s surprise, Kanzi was.

Although no one had been directly teaching Kanzi, he was paying attention. When Matata left, he needed to communicate with humans to get the things he wanted. To the amazement of all of the researchers and caretakers, he did so with the lexigram keyboard. "Researchers have learned that giving a rich, logically structured, and relevant life to a young ape will allow it to organize its intelligence in ways that are unique and exciting,” Dr. Rumbaugh says. Today, Kanzi’s son Teco is surprising the researchers who work with him at the Iowa Primate Learning Sanctuary.

After a life of working so closely with animals, it is not surprising that Dr. Rumbaugh’s views about their treatment have shifted drastically. During World War II, he spent time working on a farm where "animals were chattel that were either good business or bad business for the farm.” Now, his views about animal treatment are far more complex and nuanced: "All animals, including farm animals and animals in the wild, should be treated with more respect and care for their needs. Farm animals should not be raised in pens they can’t even turn around in. That is wrong to do. Hogs need to walk around and root for food. The same is true of chickens. These animals have their own sense of what is going on, and they are distressed. We should strive to be more humane.”

Hopes for the Future

As for the future of research, Dr. Rumbaugh would like "to see the whole of salience theory explored for predicting what animals and we will learn and what they will do with what they have learned.” He considers "the work of Charles Menzel illustrative” of the kind of research that he likes to see at the Language Research Center. Dr. Menzel "has shown that Panzee, a chimpanzee, has a superlative ability to observe where items are hidden on the forest floor and ask for their retrieval even days later by a person who does not know where they were hidden. She remembers what is in the bags—up to 20 of them—and where they are hidden. She asks for them in order of their food value (to her) and the quantity of food in them. She directs the person by pointing, using body orientation, and vocalizations.” Michael Beran and others have shown that Panzee’s comprehension of spoken language is superior to her comprehension of lexigrams. As the research team learned with Kanzi, when a dedicated staff raises a chimpanzee "in a language-rich environment” they are capable of more than scientists thought possible just a few decades ago. Although current studies with the apes are quite different from the language acquisition studies of prior years, they still inform the basic question, "What do these symbols mean to the apes?”

Beyond the specifics of future research, Dr. Rumbaugh says, "It is myopic when people conclude that there is nothing of consequence to learn from comparative studies with animals. We are not as unique as once thought. And early rearing is very important for the development of optimum intellectual development both in humans and animals. I strongly believe that comparative psychological studies remain basic to understanding human psychology.”

To learn more:
Book: Dr. Rumbaugh’s new book is available on Amazon at All proceeds from the book go directly to support the apes.


Rumbaugh, D. M. (2013). With apes in mind; Emergents, communication, & competence. Retrieved from

Rumbaugh, D. M., King, J. E., Beran, M. J., Washburn, D. A., & Gould, K. L. (2007). A salience theory of learning and behavior—With perspectives on neurobiology and cognition. International Journal of Primatology, 28, 973–996.

Dr. Duane Rumbaugh is a Distinguished Member of Psi Chi, and has received far more honors and awards than it is possible to list here. He has worked in the field of comparative psychology for 60 years, and his work has been supported by the National Institute of Child Health and Human Development (including a current grant HD-060563) and by other agencies. He has made immeasurable contributions to the field. Most recently, he authored With Apes in Mind, the story of his research with Lana, Kanzi, Panzee, and many more interesting characters from a personal and highly entertaining perspective. All proceeds from the sale of With Apes in Mind will go to support the animals at the Iowa Primate Learning Sanctuary (home of Kanzi and five other bonobos), and those at the Language Research Center (where Lana, Sherman, and Panzee reside). The book is for sale on both the Kindle and iTunes platforms, and will soon be available in paperback.

Copyright 2013 (Vol. 18, Iss. 1) Psi Chi, the International Honor Society in Psychology

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