SEATTLE (AP) -- They wag their tails, chase after balls and respond well to gentle pats on the head, but can these robotic pooches live up to the role real pets play in children's lives?

That's one of the questions two University of Washington researchers are trying to answer in a study examining how kids interact with Aibo, a sleek, cat-sized robotic dog Sony first released three summers ago.

"If a kid establishes a sense of Aibo as a friend, that Aibo will be there for them, can they just put him in a closet and walk away?" asked Batya Friedman, an associate professor at UW's Information School.

Friedman and her husband, Peter Kahn, a research associate and professor in the university's psychology department, have spent the last year and a half comparing the differences between how 80 preschoolers play with Aibo versus a cuddly, stuffed dog.

At a research demonstration on campus Tuesday, kids crowded around an Aibo, answering various questions posed by one of the research assistants who helped out with the study.

"Can Aibo feel happy?" Annie Foreman, a senior majoring in informatics asked the group.

"Yes!" shouted 4-year-old Nicholas Navin. When asked how, the boy said, "Umm," paused for a while, then said, "When I make him do tricks and play with him."

Most kids said they thought the silvery, multi-jointed machine wasn't alive, but 5-year-old Arianna Stoltz offered a theory to the contrary. Aibo's alive, she said, "because he can move."

Navin shot back, "He's not alive, because he lights up different colors, and dogs don't do that."

Most concurred there's no need to walk or feed a robo-pet. As Navin put it, "He doesn't pee and poop because he's pretend, and he doesn't eat anything."

In a recent visit to a fifth-grade classroom, Kahn said he was troubled by some of the reasons kids gave for wanting an Aibo instead of a real pet.

"I don't have to feed it," he recalled one child saying. "I don't have to take care of it. If I go away, I don't have to worry about it," another added.

As the father of a 9-year-old girl, Kahn said he was a bit appalled. "It's worrisome when the kids are so readily accepting of this technology," Kahn said, "and they don't seem to be aware of what they're missing."

Sony spokesman Jon Piazza downplayed such concerns, noting that most Aibo consumers are adults. With the first-generation model, 90 percent of the people who bought the $ 2,500 robots were 30- to 45-year-old men. The second-generation model, released in 2000, was most popular with consumers in their 20s.

The latest version, complete with voice-recognition software and digital photography capability, costs $ 1,500 in the United States and has been a hot seller for teens and pre-teens, Piazza said.

Friedman and Kahn plan to spend the next year analyzing their data before publishing any conclusions. They're also collaborating with some researchers at Purdue University, studying how the elderly interact with Aibo. The pooch was a hit during visit at an assisted living center in Seattle.

"We are hopeful there will be real benefits for the elderly, who may no longer be capable of caring for real animals," Kahn said. "However, with children, in those early stages of development, we have concerns about what happens when they fall prey to accepting robotic companionship without the developmental benefits that real companionship involves."

Sony officials argue they're simply filling a niche.

"It's never been Sony's intention to substitute Spot or Fido, but Sony does want to give you as close to an organic experience as possible," Piazza said from the company's San Diego office.

Piazza has two Aibos, one named Circuits, the other Purple Haze. "I was kind of leery myself at first," he said, "but once you name it and you see it respond, it's like it's alive."

That's the problem, according to Kahn and Friedman.

"Either you start treating people like machines or machines like people," Friedman said, "so your ability to make those distinctions and take responsibility for the technology becomes compromised."

Massachusetts Institute of Technology Professor Sherry Turkle has done similar research on Aibo in recent years and has studied other robotic toys for more than two decades.

"We are messing with very serious issues when we start presenting digital creatures as alive," said Turkle, director of MIT's Initiative on Technology and Self. "Robotics research has to be done with an increasing respect for the fact that very significant buttons are being pushed in the lives of people - the lives of children, especially."

Copyright 2002 The Associated Press. All rights reserved.