For the last 22 years, Dr. Pepperberg has been teaching Alex, who is 23, to do complex tasks of the sort that only a few nonhuman species -- chimpanzees, for instance -- have been able to perform. But unlike those other creatures, Alex can talk, or at least, he can vocalize. And, Dr. Pepperberg says, Alex doesn't just imitate human speech, as other parrots do -- Alex can think. His actions are not just an instinctive response, she says, but rather a result of reasoning and choice.
Assertions like Dr. Pepperberg's are at the center of a highly emotional debate about whether thought is solely the domain of humans, or whether it can exist in other animals. Although many people are intrigued by the idea that animals may be capable of some form of abstract reasoning and communication, scientists often ascribe what looks like clever behavior to mimicry or rote learning or even, in some cases, unconscious cues by a trainer.
Dr. Pepperberg, listing Alex's accomplishments, said he could identify 50 different objects and recognize quantities up to 6; that he could distinguish 7 colors and 5 shapes, and understand "bigger," "smaller," "same" and "different," and that he was learning the concepts of "over" and "under." Hold a tray of different shapes and colored objects in front of him, as Dr. Pepperberg was doing the other day as a reporter watched, and he can distinguish an object by its color, shape and the material it is made of. (Dr. Pepperberg said she frequently changed objects to make sure Alex wasn't just memorizing things and that she structured experiments to avoid involuntary cues from his examiner).