Do Animals Think?

By Clive Wynne, published November 1, 1999 - last reviewed on June 9, 2016

Benji left us about 15 years ago for that great kennel in the sky. But recently I've been thinking about him a lot. Was he really conscious? Could any animal have consciousness like we do? Does it matter whether animals are conscious or not?

For many, it is a matter of life and death. On the one hand, animal research has helped prevent some of the most pressing human diseases, including hepatitis B, hepatitis C, "mad cow" disease, malaria, cystic fibrosis and emphysema. On the other hand, this research is performed largely on chimps, our closest nonhuman relatives, with whom we share 98.4% of our genetic material, and on the other great apes, with whom we are similarly biologically close.

Some people feel this connection is strong enough to warrant special treatment. An international group called the Great Ape Project is pushing the government of New Zealand to adopt a bill that would give some human rights to chimpanzees, gorillas and the rest of the great apes. The Great Ape Project is lobbying the United Nations to adopt a declaration on the rights of great apes modeled on the UN declaration On the Rights of Man. The group believes that apes are "conscious" and so deserve legal protection of their right to life and freedom from imprisonment and torture.

If great apes were shown to have consciousness something like our own, I would consider it among the scientific discoveries of the century. I would then agree with the Australian philosopher and founder of the animal rights movement, Peter Singer, that performing medical experiments on chimps would be like experimenting on orphan children. That's a pretty chilling thought, and no amount of human suffering saved could justify such an action. But before we close down the laboratories and stop searching for a vaccine against AIDS, we had better take a long hard look at the evidence for ape consciousness.

What is Consciousness?

The definition of consciousness has eluded us for over a century, but many psychologists as well as supporters of the Great Ape Project agree on three classes of evidence: language, self-awareness and "theory of mind."

LANGUAGE: The mutual possession of language is surely one of the strongest indications that the being you are talking to is conscious like you. Through their work teaching language to chimpanzees, many researchers have found glimmers of "conscious" light in animals' ability to communicate:

o Washoe, a chimpanzee, has been taught to use American Sign Language. Today, she is enjoying a boat ride on a lake with her trainers when a swan comes into view. Washoe has never seen a swan before and has no sign in her vocabulary for such a thing. "Waterbird," she signs excitedly to her human companions.

o Kanzi, a pygmy chimpanzee, first learned to communicate with symbols by watching his mother's lessons. His trainer, Sue Savage-Rumbaugh, is testing him for his comprehension of sentences. "Would you please carry the straw?" she asks him. Kanzi picks up a straw. "Give the trash to Jeanine"--Kanzi picks up the trash and brings it to the other trainer. Koko, a gorilla, has been learning American Sign Language from her trainer, Francine Patterson, for over 20 years. In April 1998, Koko was the first nonhuman to go live on the Internet. She answered questions about her life and hopes, her desire for a baby and her dreams of freedom.

SELF-AWARENESS: Self-awareness is another key ability of conscious beings. To be conscious is, firstly, to be conscious of one's self--to be aware that 'I' am a being separate from others and the world around "me."

o Megan, a chimpanzee, is in training with Daniel Povinelli. She has had a mirror in her quarters for several months. Today, Povinelli is testing her self-awareness with a method developed by Gordon Gallup. This morning, Megan was anesthetized. While she was unconscious, a spot of bright red nontoxic ink was daubed on her forehead. Now it is afternoon and she is fully recovered from the anesthetic Sure enough, the chimp looks in the mirror and then scratches at the spot on her forehead. To some, this proves that Megan has recognized herself and is consciously self-aware.

THEORY OF MIND: Theory of mind is an awareness that others have minds as well: "I am not the only conscious being. Others are conscious and I take this into account in my dealings with them."

o Sheba is another chimpanzee being trained by Daniel Povinelli, but in quite a different experiment. Sheba has been watching one trainer put food into one of four cups. She can't see which cup because they are hidden from her view--but she can clearly see that this trainer (we'll call him the "knower") had some food and put it in a cup. Now the knower comes back into the room together with another trainer (the "guesser"). If Sheba has a theory of mind--an awareness that the trainers have a conscious awareness of their own--she should know that the guesser did not see where the knower put the food.

The two trainers are in the room. The knower points to a cup; the guesser points to a cup. The knower points to the cup into which he had placed food earlier; the guesser--well, he just guesses. What does Sheba do? She chooses the cup to which the knower points.

Aping Language

Herb Terrace of Columbia University in New York is one of the original researchers on language in apes and now a critic of such attempts. During the 1970s, he coordinated a project teaching American Sign Language to Nim Chimpsky, a young chimpanzee named in humorous honor of the famous linguist Noam Chomsky. Whereas Terrace had hoped that Nim would pick up sign language just by living among a community of people using it, he was disappointed to find that it was only possible to get Nim to learn by bribing him with treats.

When funding for the project ran out, Terrace had time to consider his data, and he began to notice certain things: He realized that often Nim was using signs in his response that the trainers had used in their question--in effect just echoing what had been said. He also noted Nim's spontaneous signs were almost always demands for something. He rarely asked questions or commented on the world around him, the way even young children do. And Nim's vocabulary remained small-only about 125 signs after three year's training.

Finally, Nim's utterances were typically very short--only one or two signs--and completely ungrammatical. The chimp's longest recorded utterance was "Give orange me give eat orange me eat orange give me eat orange give me orange give me you." Easy to understand, but without respect for basic grammar, which even the youngest and least educated humans comprehend.

The other ape language researchers pounced on Terrace, claiming that his work contained critical flaws. They pointed to the "creative" use of words, like Washoe's "waterbird" to describe a swan--surely this showed a deeper understanding of language than Nim had demonstrated. How do we know that Washoe was referring to the swan? She could have just been naming two things she saw, water and a bird.

Sue Savage-Rumbaugh has drawn attention to the fact that Kanzi appeared to pick up symbolic language simply by observing her mother's training. This is an interesting observation, but it does not consider the fact that Kanzi is being rewarded for her use of symbols--she is usually given the thing that she names.

Savage-Rumbaugh identifies Kanzi's success in obeying commands such as "Would you please carry the straw?" as evidence of a grammatical understanding. But was any other interpretation possible? When Kanzi correctly carries out this instruction, does this mean that she understands the structure of the sentence--that she should carry the straw, and not that the straw should carry her? Though a chimp may carry straw; straw will not carry a chimp! Although different interpretations may be grammatically possible, in reality, only one interpretation was practicable under the circumstances.

Not All Smoke And Mirrors

What of Megan, the chimp who wiped the ink off her forehead? Is she showing evidence of advanced consciousness? Gordon Gallup argues that for an animal to recognize itself in a mirror, it must have self-awareness in a form not so different from our own. He is impressed by the observation that great apes are the only mammals to show self-recognition in a mirror (although in the 1980s, Robert Epstein, Robert Lanza and B.F. Skinner demonstrated that, with training, even pigeons can pass Gallup's mirror test, which means it may not be so tough).

The problem with Gallup's interpretation is that there are people who cannot recognize themselves in mirrors, and yet nobody doubts they are fully self-aware. Blind people cannot recognize themselves in mirrors but we have plenty of other indications that they are self-aware. People brought up in communities that do not have mirrors do not instantly recognize themselves when they are first shown their own reflection. There is also a form of brain damage called prosopagnosia, which leads to an inability to recognize faces. In extreme forms of prosopagnosia, the patient may not even recognize his own reflection.

Conversely, there are people who have problems with self-awareness, but who recognize themselves in mirrors normally. People who suffer from autism have an impaired ability to see themselves as others view them, and yet they recognize themselves in a mirror with no problem.

In light of these revelations, it does not make sense to treat mirror recognition in chimps as a measure of self-awareness.

No Monkey Business

Povinelli's "guesser-knower" experiment was partially modeled on theory of mind tests in children: A child or chimp who has an awareness that others have minds, can readily see that one trainer knows something that the other doesn't.

If you or I were put in the guesser-knower experiment, we would almost immediately choose the cup the knower points to because we have a theory of mind that guides our behavior. Sheba the chimp, however, required hundreds of training sessions before she began consistently choosing the cup pointed to by the knower, and even then she was successful only 75% of the time. This suggests she was gradually learning an association between a stimulus (the "knower") and a reward, and not treating them as people with minds.

Human Minds in Ape Bodies?

Much has been made of the fact that chimps are our closest living relatives. But DNA doesn't tell us anything about what traits and abilities two species have in common. In making claims for the intelligence of dolphins, no one feels inhibited by the fact that dolphins' closest living relatives out of the ocean are cows and sheep.

Chimpanzees and other apes are wonderful animals, fully worthy of ethical treatment and protection. But they are not human beings. They are not 98% human; they are not even half human. They are 100% animals on their own terms.

The desire to see animals as human is unbearably strong. But if we are going to consider closing down AIDS and hepatitis research and giving "human" rights to chimps, we had better be certain we are not just giving in to a natural but base less, anthropomorphic tendency without solid evidence to back us up.

I am not disappointed that the attempts to find human-like consciousness in apes have failed. On the contrary, I find it profoundly exciting and liberating. We are surrounded on this planet not by things-like-people dressed in fur and feathers, but by myriad beings, each with its own unique psychology. As an animal psychologist, I can't think of any challenge more exciting than trying to understand animals in their own right and not just as dumber versions of ourselves.

How Human Is Enough?

In Wynne's impassioned article, he implies that humans are the only conscious beings in the world. Then he qualifies that consciousness by describing it as "something like our own." But how "human" must animal consciousness be?

Consciousness is not a tidy all-or-nothing entity; it varies with age, culture, experience and gender. And if animals have conscious experiences, these presumably vary widely as well. it might help to consider what an animal might be conscious of. It seems more likely than not that some animals are aware of objects and events that are critically important in their lives, such as what food is tasty, which animals are dangerous predators, and whether particular companions are friendly or aggressive.

The fact is that we lack adequate methods to identify conclusively what behavior is "conscious." But scientific study of consciousness is undergoing a renaissance as reflected in recent books, conferences and journals. And these investigations have begun to include nonhuman consciousness. In particular, Alan Cowey of Oxford University and Petra Stoerig of the Institute of Medical Psychology at Ludwig-Maximilians University in Germany have developed procedures by which a monkey can signal whether or not it is consciously aware of a particular visual stimulus.

This and other recent developments provide empirical and objective support for the conclusion reached by Stephen Walker at the University of London in his !983 book Animal Thought (Routledge): "Our organ of thought may be superior, and we may play it better, but is surely vain to believe that other possessors of similar instruments leave them quite untouched."

--A Response By Donald Griffin, Ph.D.


If A Lion Could Talk, Stephen Budiansky (Fourth Estate, 1998)

Animal Learning and Cognition (2nd ed.), John Pearce (Psychology Press, 1997)

PHOTO (COLOR): A Bronx Zoo visitor monkeys around with Huerfanita, a female lowland gorilla at the new Congo exhibit, June 1999. Below: A captive orangutan peers through the bars of his cage in Borneo.

Adapted by Ph.D and Ph.D.

A Response by Donald Griffin, Ph.D.

Clive Wynne, Ph.D., is a senior lecturer at the University of Western Australia in Perth, Australia

Donald Griffin, Ph.D., Professor Emeritus, The Rockefeller University, is associate of the Museum of Comparative Zoology at Harvard University, and has written seven books, including Animal Minds (University of Chicago Press, 1992).