Alex is a celebrity. His accomplishments are detailed in numerous articles. He understands mathematics, uses polysyllabic words, loves posing for the camera and is an icon in his scientific field. His mental capacity stupefies those who watch him; he adores cashews and loves meeting new people. Alex is one of the most intelligent African Gray parrots in the world.According to a recently completed 29-year-old study conducted by Prof. Irene Pepperberg (PSYC), African Gray parrots could have similar cognitive abilities as young children.

"They're about the same intelligence as a five-year-old child but their communication skills, at least as far as we've looked at in the lab, are only about that of a two-year-old," she told The World Today in July.

Her experiments involving Alex and other African Grays have tested a number of abilities: distinguishing between larger and smaller objects, identifying pairs, counting, determining absence, understanding object permanence, using mirrors and labeling objects.

"We give him tests that are very similar to those given to children," Pepperberg said in an interview with the Justice. "Because he can talk, he can answer direct questions like 'what color?', 'what shape?', 'how many green keys?'"

Recently, Alex has been participating in counting exercises. When inquired about one set of objects, Alex spontaneously responded, "none." Pepperberg said Alex learned of the concept of zero in an entirely different context. Independently, Alex transferred that knowledge to an unrelated situation.

Pepperberg said that there are several reasons why Alex's understanding of zero is significant.

"One: He initiated the trials himself. Two: Western civilizations did not really understand or use zero until about the sixteenth century," she said. "Alex's concept of zero is more primitive than that of an adult human, but it is comparable to that of a young child."

While conducting some of these activities with a different African Gray Parrot, Griffin, Pepperberg's lab manager Arlene Levin-Rowe placed different objects-like rings, corks and a toy truck-in front of "Grif," who was able to verbally identify the objects most of the time.

Not only are Pepperberg's subjects able to identify characteristics of such objects, but through these experiments evidence of individual personalities emerged. When Griffin was unable to identify the truck, his face displayed a blank expression and he turned his head away, Pepperberg said.

Griffin exhibited excitement, however, when a student lab assistant produced a ball of wool. Upon recognizing the object, Grif shouted "wool!" in an animated tone.

Alex is more forthcoming when trying to telegraph his confusion.

"When Alex does not know an answer, he hiccups," Levin-Rowe said.

Pepperberg said her fascination with birds is rooted in her childhood ownership of Australian parakeets. She said their ability to talk and associate words with appropriate situations fascinated her.

While Pepperberg was working toward her doctorate in theoretical chemistry at Harvard University, she saw a series of television programs investigating animal communication. The shows discussed talking dolphins, singing birds and the sign language of apes.

"I wondered why no one was trying to study parrots," Pepperberg said. "For these were birds that could actually speak."

Pepperberg said she became interested in African Gray Parrots because they "are among the clearest of talkers, and when [I started my] research, papers had already shown that they were quite intelligent."

Pepperberg said her study has yielded practical applications. Because her models provide a way of understanding the transition from simple to complex learning, she has inspired new ways of teaching autistic children.

"My collegue Diane Sherman, of NewFound Therapies in Monterey, Calif., has adapted our training procedure for intervention programs with autistic children," Pepperberg said. "No child has achieved fully normal levels of behavior, but all have improved dramatically."

So how big is the gap that exists between humans and animals?

Hiccup.