Robots have been the stuff of popular culture for so long that We think of them mostly as a fun. In the next decade they will finally become practical beyond factory assembly lines. Granted, they won't perform. the wonderous stunts they do in movies the first generation of 'real' robots may seem a bit crude. But by the end of the decade, we may well encounter tiny robots cooking hamburgers in fast - food restaurants, mopping up shopping malls, even delivering meal trays in hospitals. Two factors are pushing the development of robotics: technology and economics. Artificial intelligence is the key to a successful robot, but some of the simplest tasks for a human mind are difficult for a robot. One example: the ability to look at the comer of a room, where walls and ceiling meet, and know that the corner goes in, not out. Easy for humans, very tough for real -world R2D25. But new neural-network computers, which more closely resemble the human brain ,look particularly promising for teaching robots how to adapt to: their surroundings. Economics is the key to the acceptance of robots. As declining birthrates lead to a shortage of entry- level workers in much of the industrialized world, researchers are designing robots that can manage at least portions of such jobs as burger flippers or hospital orderlies. Fast -food robots will probably cook and package food humans will still greet the public at the counter and make incorrect change. By the late 90's,improved robots will be inexpensive enough to serve as aides for the disabled, giving even quadriplegics the ability to feed themselves and perform. office work. Not all robots will be so benign. Another model in production is a security guard designed to wander deserted warehouses and signal a human guard when it encounters intruders. At least one American firm has designed an armed security robot capable of firing a weapon. And the long-promised home robot? This little electronic servant, capable of delivering a frosty beer from the fridge, picking up the kids' toys and washing the occasional window, probably won't be a mass - market item in the 90's--unless we modify our homes to accommodate them. Every room would need to have tiny radio beacons to tell the robot where it is, and staircases would need special construction for easy robot access. Sound unlikely? Perhaps. But in 1890 a person might have thought it unlikely if he had been told that the entire urban landscape of the planet would be modified to accommodate the automobile. In the next decade, Robots will become practical because of all but one exception that ______.