PEOPLE HAVE spent ages pondering whether animals think. On Oct. 27, the public will be able to learn more about our mute cousins when Think Tank opens at the Washington Zoological Park.
When you come to Think Tank, bring your reading glasses and be prepared to spend some time. "Think Tank is a cross between a zoo and a museum exhibit," says Lynn Donick, chief of the National Zoo's Division of Exhibit Interpretation and Think Tank project manager. "The subject is complex, and we've included a lot to read."
As you enter the exhibit, a kaleidoscope of photographs of animals in action will catch your eye while a series of monitors displays quick vignettes -- a spider weaving a web, a human sky-diving, a gosling following its mother. Each of these images poses the question: Are these creatures thinking?
To find out, you might do a series of exercises or flip up the flaps covering in-depth explanations of information given more briefly
in cartoons and blurbs on the reader rails. What do scientists really think about the cognitive abilities of seeing-eye dogs? Lift up the flap and see.
In the next section, you will encounter two large and touchable bronze brains and display cases filled with brain models in wax and real brains in bottles. Confronted with the thinking organs of a whale, an elephant, a human, an orangutan, and squirrel, you may begin to wonder about the question of the brain size to brain capacity.
In the "smart" (or language) room, you can watch the orangutan school or play an interactive game to test how well you use language. Panels around the area show "open the big red bag" in 30 different languages (including orangutan symbols), explain what language is, and trace the history of what we know about it through the work of a dozen language researchers.
The real attractions here are the macaques -- with their constant display of threat yawns, lip-smacking greetings and affectionate grooming.
"Very few museum or zoo exhibits have ever attempted to show something that's unobservable," points out Dr. Benjamin Beck, the zoo's associate director for biological programs. Over the past 10 years, his plan to renovate the Monkey House evolved into the wildly innovative Think Tank. "But we are spending $4 million on an exhibit of something you cannot see, taste, hear or smell. Everything we know about animal thinking has to be inferred from the animals' behavior."
Thirty years ago, the ability of various animals to use tools was viewed as the most easily observable sign of intelligence. At Think Tank, researchers also will look at three other factors: evidence of animal communication and "languages," animal societies and willingness to cooperate for the good of the group.
Brains are expensive
"A big brain is an expensive piece of adaptive equipment," James Shreeve reminds us in his forthcoming book, "The Neanderthal Enigma: Solving the Mystery of Modern Human Origins" (Morrow). "You don't evolve one if you don't use it."
NTC Bigger animals naturally have bigger brains -- just as they have bigger limbs. But while an elephant has a bigger brain than a shrew, this does not automatically mean that elephants are "smarter" than shrews.
Because each species is expert in the things it must do to survive, it is no easy task to compare one to another. If a horse, for instance, is asked to stomp a lever to make a response in a laboratory test, what should a fish be expected to do? And in addition to differences in physical capabilities, differences in sensory ability dictate that rats will do badly when asked to distinguish between two shapes but will rack up a far better score than a human when asked to discriminate among smells.
But motivation can be just as crucial as ability. Some animals are just not interested in playing the laboratory test game, and even the question of rewards is tricky. A horse would do miserably on a test where the reward was a worm, just as a fish would be unwilling to work for a carrot.
It is obviously easier -- and more satisfying -- to compare the thinking capacity of animals within a closely related biological group. Scientists will cautiously allow that primates, for instance, whose brains are relatively large compared to their body weight, tend to do better on standardized problem-solving tests than do closely related species with relatively smaller brains.
But even that statement has to be qualified.
"It may turn out that the intelligence of humans, chimps and gorillas and monkeys is simply not comparable," says Dr. Beck. "Finding equitable ways to explore thinking processes is one area Think Tank will explore."
Thinking is hard to define even if you know it when you see it.
As National Zoo researchers have defined it, thinking starts with an image. The thinker then forms an intention and a strategy for achieving it. But even this connected chain of mental events is not sufficient to qualify as thinking at the National Zoo, where researchers decided that thinking must also be flexible enough to come up with Plan B should Plan A fail.
This final requirement rules out cases of learned response -- such as dogs trained to sit on command. Salmon hard-wired to migrate upstream to their spawning grounds are the classic case of being stuck with Plan A. They know where they are going and show an almost maniacal resolve to get there. But if their way is blocked, salmon will die rather than choose another place to spawn.
The zoo's beautiful old Monkey House-turned-Think Tank has two outdoor enclosures, painted a pleasing copper green, for the six orangutans and Sulawesi macaque monkeys that will take part in thought research.
The stars of the show
The orangutans are Think Tank's star attractions. "Because they are so rare, research on them has been sparse," notes Think Tank's curator, Lisa Stevens. "Anything we can learn here about how orangutans think will break new ground."
The orangutans will get from the Ape House to school in the Think Tank by swinging over the heads of visitors on the walk below. The orangutans get around on on the "O-line," plastic-coated steel cables suspended on eight 44-foot towers. The cables simulate rain forest vines.
The day I visited the Ape House, Azy -- a teen-age orangutan -- sat hunched in a corner. But when Rob Shumaker, coordinator of the Orangutan Language Project, showed up, Azy ambled over on the double. Mr. Shumaker is teaching Azy and five other orangutans to recognize picture symbols for apple (a wavy line) and banana (a diagonal line with a circle in the middle).
Mr. Shumaker and his pupils have since settled into a regular routine of half-hour classes. Any longer and the orangutans' attention tends to wander.
Slouching forward, Azy peered at the cards through perplexed looking, close-set eyes then pointed daintily through the mesh to the correct one. "Good!" said Mr. Shumaker, giving Azy the fruit he had just identified.
Wrong answers are recorded, but the animals are always given a second try at earning the reward. Students are judged to know a word when they can identify a symbol 18 out of 20 times five days in a row. Once their symbolic vocabulary is large enough, Mr. Shumaker plans to teach the orangutans how to use syntax to make sentences -- a goal achieved with other primates.
With its O-line and Think Tank, the National Zoo has stretched the boundaries of what a zoo can do. With its controlled research into animal thinking, it stands poised to stretch our understanding of the limits and origins or consciousness.
And Think Tank is more fun than a barrel of monkeys.
PD Elizabeth J. Sherman is a free-lance writer based in Washington.