(3 of 9)
But the skepticism also served as a challenge. A number of scientists launched innovative probes of animal intelligence, while those who remained in language work designed careful experiments to meet the objections of critics. Their aim is to determine, as precisely as possible, what animals know and how well they can communicate it. The result is that animals are once again talking up a storm, as well as demonstrating other intellectual skills. Most scientists now take seriously the flood of new evidence suggesting that other species share with humans some higher mental abilities.
The Lessons of Kanzi
No animal has done more to renew interest in animal intelligence than a beguiling, bilingual bonobo named Kanzi, who has the grammatical abilities of a 2 1/2-year-old child and a taste for movies about cavemen. The 12-year-old pygmy chimpanzee lives with a colony of other apes in a cage complex on the wooded campus of the Georgia State University Language Research Center, near Atlanta. Under the tutelage of psychologist Sue Savage-Rumbaugh, he makes his desires known either by pointing to symbols printed on a laminated board or by punching the symbols on a special keyboard that then generates the words in English. While Kanzi cannot speak (apes lack the vocal control to form words), he understands spoken language.
In the time-honored fashion of ambitious young interns, Kanzi became involved in language experiments by catching the boss's eye. Savage-Rumbaugh noticed that the young ape was learning words she was struggling to teach his mother Matata. The language was a system of abstract visual symbols developed by Savage-Rumbaugh's husband Duane Rumbaugh during his first language experiments with chimpanzees. "If Kanzi could learn without instruction, I wondered, Why teach?" says Savage-Rumbaugh. From then on, Kanzi learned language much the way human children do: by going through the ordinary activities of his day while humans spoke in English and pointed to the appropriate lexigrams on the portable boards.
Kanzi soon began using the lexigrams as a means of communication, requesting games, treats and activities. Eventually he learned to combine two or more symbols to convey his desires. When, for instance, he wanted to watch a favorite movie, Quest for Fire, he would ask for "Fire TV" (Kanzi also adores Greystoke, a Tarzan movie).
Kanzi's most noteworthy achievement has been to demonstrate a grasp of grammatical concepts such as word order. Savage-Rumbaugh and psychologist Rose Sevcik created an extended experiment to compare the ape with a two-year-old girl named Alia in responding to commands expressed in 660 spoken English sentences. The sentences combined objects in ways that Kanzi and Alia were unlikely to have encountered before: "Put the melon in the potty," or "Go get the carrot that's in the microwave."
Through most of the experiment, Kanzi and Alia were neck and neck. At the end, however, Alia's language skills began to outpace the bonobo's, while Kanzi's grammatical comprehension topped out at the level of a 2 1/2-year-old. Though not impressive by human standards, even that toddler level implies vastly more sophisticated abilities than critics have acknowledged.