In the 16 years since the first of many chimpanzees was taught to talk, using the sign language of the deaf, psychologists have yet to agree on whether the animals use language in the human sense. Now they will have to grapple with a related problem: A Japanese researcher reports that he has taught a chimp to count -- up to six.

The ape, a 5-year-old female named Ai, has been trained to look at a group of objects and give not only their name and color but also their number. Ai looks at objects presented by the scientist and presses the appropriate keys on a keyboard to indicate their name, color and number. Abstract graphic symbols represent words corresponding to each of 14 names and 11 colors. The number keys bear Arabic numbers.

If Ai is shown three red pencils, she presses three keys, one for each category of information. Ai chooses the order, usually giving her response as "pencils red three" or "red pencils three." Ai achieved her ability after a little more than 68 hours of training, according to Tetsuro Matsuzawa of Kyoto University's Primate Research Institute. He reported his research in Nature. He said Ai gives correct responses 97 percent to 99 percent of the time.