South Jordan » The phrase "motion pictures" usually refers to the movement on the screen.

In one Utah movie theater, the motion also comes from where you're sitting.

Twenty-eight "motion enhanced" seats, which sway and shake in harmony with the on-screen action, have been installed in theater No. 13 at the Megaplex 20 at The District. Moviegoers can buy tickets for these moving seats starting today at screenings of Disney's action-adventure "Prince of Persia: The Sands of Time."

"This is designed to intensify the experience, ... to make it more immersive," said Jeff Whipple, marketing director for the Larry H. Miller Enterprises-owned Megaplex chain, which operates 70 screens at five Utah locations.

Megaplex has partnered with D-Box Technologies, a Quebec company that first developed the "motion enhanced" seating for home-theater systems and has expanded into commercial venues. D-Box has installed its seats in theaters in 26 cities, most of them in the United States (with two more in Canada and one in Osaka, Japan). The Megaplex 20 theater is the first in Utah to install the D-Box seats.

D-Box has also made deals with Hollywood studios that allow the company to write the code that synchronizes the seat's movements to the action in blockbuster films, said Guy Marcoux, D-Box's vice president for marketing. Upcoming titles that Megaplex 20 will bring to Theater No. 13 include the supernatural thriller "Jonah Hex" on June 18 and the mind-twisting heist drama "Inception" on July 16.

Writing the code is a laborious, frame-by-frame process that takes between 300 and 500 work-hours to complete, Marcoux said.

The movements are more subtle than similar technology used in theme-park rides. Moviegoers can adjust the seat's settings -- low, medium, high or off -- to their tastes.

Because of the costs of the seats and coding the films, moviegoers will pay extra for the kidney-rattling experience: an $8 surcharge on top of the regular ticket price. That's on top of $8.50 for adults, $6 for children or for matinee screenings at the Megaplex 20. Seats are programmed to work only if a ticket is sold, so it won't do any good to buy a regular ticket and then sneak over to the more expensive seats.

Will Utah moviegoers pay the extra price?

"It was actually very cool," said Katie Stuart, a Sandy resident who tried out the D-Box demonstration model in the Megaplex lobby this week. "It would definitely go great with 3-D."

Innovations such as 3-D and "motion-enhanced" seats are a high-tech upgrade to the gimmicks Hollywood brought into theaters in the 1950s, when movies were losing business to the new entertainment, television.

"People are looking for the next level of entertainment," Whipple said. "Color, stereo and surround sound were innovations for the time, too."

The B-movie impresario William Castle famously raised interest in his 1959 thriller "The Tingler," in which a beast lived at the base of people's spines, with a gimmick called "Percepto." Castle strategically installed large joy buzzers in theater seats, prompting audience members to scream when they felt the shock.

D-Box's technology is far ahead of anything Castle imagined, Marcoux said, because moviegoers today won't be fooled by joy buzzers.

"If it's not timed perfectly with the action," Marcoux said, "it wouldn't be compelling and people wouldn't like it."