STATE COLLEGE, Pa. (AP) _ A Penn State University professor experimenting with computer games for pigs says the animals, like primates, can be taught to use icons on a computer screen to relay their thoughts to humans.

``Pigs always have their eyes open for their next mouthful, so they are always surveying the environment,'' Stanley Curtis told The Philadelphia Inquirer. ``They are very alert, and if they see some food at a certain place, they have to figure out how to get to it.

``They solve problems every day, and they have an ability to discriminate, so it should come as no surprise that their intelligence is high.''

The idea, he said, is to get pigs to first recognize symbols for a word or two, such as ``want'' and ``heat.'' Someday, he believes, a pig that would like the heat turned up will be able to join the two symbols.

From there, he predicted, strings of words can be put together into sentences.

The project is supported by about $20,000 in research funds from a Penn State grant, national and Pennsylvania pork producer groups, and Purdue University's agricultural research center.

The goal, Curtis said, is to provide the best environment not only for pigs, but for other farm animals such as sheep and cows. Farmers, he said, do what they think is best for their animals. But what if their choices are wrong?

``Wouldn't it be better if we could communicate with the animals directly and say, `How do you feel today?' '' Curtis said.

Not everyone in agriculture thinks it's necessary for a pig to have computer skills to make its feelings known.

``A good animal husbandry person has looked at signs for years and has always been able to look at a group of animals and read them as to whether they're comfortable,'' said Ken Esbenshade, head of animal sciences at North Carolina State University.

``I have real concerns sometimes that we try to give human qualities to animals. Even though they may have some of the same responses and feelings, and there's some reasoning power present, they are not humans.''

Curtis' plan to put pigs and computers together grew out of a July 1995 visit to the Yerkes Regional Primate Research Center in Atlanta. Curtis borrowed the program for chimpanzees and worked for a year with graduate student Candace Croney to figure out a pig-friendly system.

One of Curtis' former students, who had studied pigs' head and jaw movements, was an adviser. An optometrist studied the pigs' vision so Curtis would know where to place the computer.

Finally, a plastics manufacturer was called on to customize the apparatus to hold the computer, which rests just outside the pig pen, and to anchor the joystick.

By the fall of 1996, the first pair of pigs was playing with mock joysticks, moving them with their snouts, their cheeks, or simply holding them in their mouths.

Beginner pigs use the joystick to move a circle around the screen, trying to put it on a blue target. If they do, they receive a reward of a small food pellet.

At first, the rewards were M&Ms and Skittles, both hard-shelled candies. The pigs ate too much candy, however, and became excitable. Bland food was substituted.

While most of the pigs are still working on the circle game, one advanced porker has learned to solve a maze.

Curtis has another problem, however. The pigs don't want to stop playing at computer games.

``Nine times out of 10,'' he said, ``we have to terminate the session. Otherwise, they may play all day.''