The amount of science that goes into building a computer game is something most people do not think about, said John Clevenger, professor of computer science at Sacramento State.

Before a crowd of nearly 200 people Tuesday, Clevenger presented an extensive look at the way video games are coded, how researchers are using games to study real life, and how monsters and allies can mimic real life to appear intelligent.

“People will learn more if you put it in a game,” Clevenger said.

There is a long list of games used to teach serious subjects. For example, “Pulse” simulates a hospital environment for training health workers. There is a European game based on balancing the French national budget, and even a game that asks you to play a key role in peace talks between Palestine and Israel, he said.

More traditional video games, such as “Metal Gear Solid” or even “Pac-Man,” need artificial intelligence to help their “bad guys” interact with a player. For example, the ghosts in “Pac-Man” use a model of behavior called a “Finite State Machine.” That means they make decisions about where to move and whether or not to chase the player based on a set of rules.

“With some clever finite state machines, you can make it look like there’s some real intelligence,” Clevenger said.

There are separate rules about how individuals in a group behave, too. The computer-animated dinosaurs in Jurassic Park, for example, moved generally with the herd, but not in exactly the same way. To simulate this, computer game designers have to create rules about these actions. An animal in the herd will always try to move toward the center of the herd, and also always try to avoid colliding with other members of that herd.

Video games also need realistic movement. This means creating three-dimensional animations for activities like running, walking, jumping, falling and shooting a gun.

Basic physics — things like gravity and wall solidity — are things we take for granted in the real world. But a computer doesn’t necessarily understand them, Clevenger said. The game programmer has to put those rules into the game.

Virtual worlds are also useful, because they allow researchers to study human behavior in a controlled environment, he said. For example, a virus can be released in an online game, and its effects can be studied without harming real people.

Clevenger teaches a course on “Computer Game Architecture and Implementation” at Sac State. He is a two-time winner of the Outstanding Teaching Award.

His free lecture was part of a series by the Center for STEM Excellence on campus. STEM is short for Science, Technology, Engineering, and Mathematics.

Junior Hsing-Chang Liu, an international student from Taiwan majoring in computer science, said he doesn’t play video games much, but after hearing the lecture he was interested in trying a few out.

His friends in Taiwan play an online game called “World of Warcraft” every day. Liu said he was amazed when he started to meet people at Sac State who also play the game.

“It’s all so incredible,” he said.

Some “Serious” Games:

* Tactical Iraqi: used to train Army about culture, body language of Iraq* Incident Commander: used to train emergency response teams in crisis management* eStrat: used to train L’Oreal sales people in global marketing* Art Dealer: used to enhance memory for elderly* Re-Mission: used to teach youth about cancer

Lacey Waymire can be reached at [email protected].