Modern computers are usually "the exact antithesis" of the human bram, says Etzioni, who works in conjunction with Hewitt. While the brain works relatively slowly yet can do several things simultaneously, the computer runs quickly but can handle only one thing at a time.

Hewitt says he wants to build a computer network which works like "a human organization." In his network, computers would be in communication with each other but would retain the ability to act independently.

Hewitt's goal can be more clearly understood by using the analogy of a court of law, says Etzioni. In making decisions, several computers would contribute evidence supporting one point of view, while others would offer conflicting arguments. Through their intercommunication, the computers would together be able to arrive at a "verdict" which they could not have obtained separately.

Artificial intelligence researchers have set their sights high, and are optimistic about the chances of major breakthroughs in coming years. Most scientists at the labs feel that there is no fundamental limit to how closely machines can be made to resemble humans.

"I don't think there is anything that computers will not be able to do at some point," Poggio says.

Lozano-Perez says that one of the fastest-developing areas of A.I. at the moment is artificial hearing.

Computers which can hear and interpret single-word commands have been around for several years, he says, but only now are computers being adapted to comprehend continuous speech. Within the foreseeable future, therefore, computers may be able to verbally interact with humans.

Poggio says he predicts that within 10 years, "you will be able to buy, for the price of a car, a home robot that will clean the floor, make the beds, cook for you, etc."

Other scientists are more restrained in their estimates. Hollerbach says robots like the one Poggio described are probably a long way off. For the present, he calls attempting to embody all artificial intelligence research in a single robot "a waste of time," because while the research remains primarily in the theoretical and experimental stages, "the whole will be less than the sum of its parts."

"The kind of things you read about in science fiction are far away, and the closer we get, the more problems we run into," says Jim V. Mahony, an MIT graduate student who works with Poggio.