Do Animals Think?
Renato M.E. Sabbatini, PhD
The image of a chimpanzee at the left remind us, with an uncanny similarity, of the "thinking posture" of the famous sculpture of Auguste Rodin (which, by the way, graces the logo of Brain & Mind magazine). It poses a strong question to students of animal behavior: do animals have a mind? Are they capable of feelings and thinking? Is it true that some of their behaviors indicate that they have an inner "model of mind", i.e., are they guided by an understanding that their conspecifics (or humans) have motives and strategies to behave as they do?
The answer has tremendous implications, ranging from neurophilosophy to animal husbandry, from animal rights activism to evolutionary neurogenetics.
Of course, we should not group all animal species together in trying to get an objective answer for this quest. Practically no one would accept that lowly forms of life, such as earthworms or fruit flies, are able to think and to display consciousness, long range planning or abstract reasoning, the hallmarks of our mind. Nor would someone doubt that the great apes, such as chimps (recently demonstrated to share a whooping 98% of genome with humans) possess something that is very similar to thinking and to culture. Thus, Donald Griffin, Professor Emeritus at the Rockefeller University, and author of "Animal Thinking", has pointed out that "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." (1).
In a previous article about the evolution
of human intelligence (6), I have argued that intelligence is not
unique to humans. Human intelligence seems to be composed of a number of correlated and cooperating neural functions,
many of them already present in other primates, such as manual dexterity, highly sophisticated and accurate stereoscopic
color vision, recognition and use of complex symbols (abstract things that represent others), long-term memory,
etc. In fact, the current scientific view is that there are several degrees of complexity of intelligence present
in mammals and that we share with them many features that we previously thought were unique to man (such as symbolic
language, which has been proved to occur in apes). The study of the
evolution of human intelligence has produced evidence that there seems to be a kind of "critical mass"
of neurons to achieve human-like consciousness, language and cognition, but that these properties of the mind are
already present, albeit in a more primitive, or reduced forms, in other species which highly developed brains.
The problem is that humans know that other humans have minds like their own because we can share these experiences, by the way of symbolic language. Other animals are unable to communicate this directly to us, because they seem to lack language and introspection. However, students of ape symbolic communication, such as the those which have endowed orangutangs, gorillas and chimpanzees with the ability to use artificial languages, are quick to point that they have hard evidence for all this. Experiments with chimps Koko and Washoe and gorilla Kenzi have shown that they are able to invent new words, construct abstract phrases and express their feelings using American Sign Language or computer-based symbolic language.
Many clever experiments have been devised to prove that apes indeed have models of mind and are capable of quite sophisticated representations of reality in symbolic form. For example, chimps are able to quickly locate a hidden object in a complex environment, when they are shown where it is in a miniature mock-up. In the wild, chimps are known to elaborate complicated plots and strategies to fool competitors and obtain advantages, switch sides and doublecross each other. They know even how to lie and to deceive, the quintessential human quality which requires a capability to "observe the operation of our own mind", and to make inductive, deductive and abductive mental operations on the basis of this information. Apes recognize themselves in a mirror, a feat which all other animals are incapable of (such as exemplified by a male jaybird who nests in my garden and that every morning fights furiously with its image reflected in the window panes). Thus, they are capable of self-awareness.
Apes are also quite adept at tool manufacturing and at using them adaptively to solve problems, which indicate remarkable mental skills, a capacity for invention and creativity which were previously thought to be exclusively human. Even the sacred field of the most powerful mental operation, arithmetics and mathematics, seem to be no longer a human exclusivity (4). Experiments with rhesus monkeys done by Herbert Terrace and Elizabeth Brannon have shown that they can understand ordinal relations among the numbers one to nine.
Intelligence, communication, imitation learning and consciousness are required to produce another hallmark of our species: cultural transmission. This has been observed in many species of animals. For exempre, a group of macaque monkeys inhabiting for centuries the Koshima Island in Japan, acquired and preserved for several generations the habit of washing sweet potatoes and rice in water. Culture and group isolation leads to a much higher variety of behaviors. There are many evidences for this in alimentary, foraging, hunting and social behaviors in different chimpanzees populations.
There are many consequences of recognizing that what we define as "thinking" and "consciousness" seem to exist in apes and other animals. The first one is ethical in nature. A New Zealand animal rights group has started a Great Apes Project, which purports to grant to apes a status of "conscious, feeling and thinking" animals, therefore sparing them from animal experimentation, forced jailing (in zoos) and so on.
In my opinion they are right. Although research on hepatitis, AIDS and a host of other diseases which humans and apes share would be strongly reduced, doing experiments and killing emotional, sensitive and intelligent animals like chimpanzees is ethically troubling, the more we know about the so many similarities.
Perhaps the future will show us ways of looking into animals brains using advanced functional imaging techniques, such as MRI and PET and then decide whether they are using brain circuits similar to ours for performing higher mental functions. Human intellectual capabilities did not arose from nothing. We have inherited a large part of perceptual and cognitive processing from our primate antecessors, so it is not surprising that our closest relatives, the apes, have them also.
Renato M.E. Sabbatini, PhD, is a behavior neuroscientist with a doctorate by the University of São Paulo Brazil, and a renowned science writer. He founded the first research laboratory on neurethology in the country and one of the first in the world, after returning from Germany, where he was a visiting scientist with the Max Planck Institute of Neurobiology. He is currently an associate professor with the Medical School of the State University of Campinas (Dept. Medical Genetics) and director of the Center for Biomedical Informatics.
Copyright 2003 Renato Marcos Endrizzi Sabbatini
All rights reserved. Reproduction in all forms is forbidden
Brain & Mind Magazine 17 (May-August 2003)
An initiative: Center for Biomedical Informatics
State University of Campinas, Brazil
First Published 25.May.2003