Marek Michalowski's favorite robot looks like an oversized Easter peep that can bust some moves.

His name is Keepon, and he is best known as the star of a YouTube video -- dancing to an infectious tune by the rock group Spoon -- that has been viewed more than 2 million times.

But Keepon is much more than a disco robot.

In the hands of Mr. Michalowski, a Ph.D. student in robotics at Carnegie Mellon University, and his mentor, Hideki Kozima of Miyagi University in Japan, Keepon is also being used to study how children interact socially, and whether the robot might particularly be able to help children with autism.

Mr. Michalowski has now formed a company, BeatBots LLC, and said he hopes the revenue from selling commercial versions of Keepon will one day help fund their research.

For the past few years, Mr. Michalowski and Dr. Kozima have been tracking groups of preschool children in Japan as they interact with Keepon in their classrooms.

Despite being only 5 inches tall, Keepon has enough room to accommodate a camera behind its eyes and a microphone behind its nose. That allows the researchers to observe the children from a robot's eye view and change Keepon's movement in response to what the children say and do.

Videos of some of those encounters show the children feeding Keepon pretend food, giving it pretend medicine when it has a Band-Aid on its head, and trying to find Keepon's lost hat. It also shows the girls protecting Keepon after one of the boys whacks its head with a stick.

After shooing the boys away, one of the preschool girls turns to another, shakes her head, and says, "Boys are all the same."

The most poignant video, compiled over several weeks, shows one girl with autism who slowly begins to forge a relationship with the robot. In the early scenes, she is plastered against a far wall and won't come near Keepon. Eventually, as her curiosity increases, she pulls her caregiver by the hand to come closer to the robot. Then she touches Keepon with a xylophone stick. Then, carefully, with her foot.

Finally, she cradles the robot's head, coos toward it, and after weeks have gone by, gives it a kiss.

"You can imagine how the mother, when she was watching this video, was reduced to tears," Mr. Michalowski said, "because she so rarely saw that interaction herself, and to see her daughter doing this through the robot was very moving."

Despite having no arms or legs, Keepon manages to achieve lifelike movement with just four ranges of motion -- swiveling side to side, rocking side to side, tipping to the front and back, and bouncing.

After attending Yale University and getting bachelor's and master's degrees in computer science and psychology, Mr. Michalowski met Dr. Kozima through one of his professors and asked if he could intern with him in Japan.

During his first stint there, Dr. Kozima "put a Keepon on my desk and said, 'Do something with it,' and the first thing I thought was, 'I think Keepon wants to dance.' "

Mr. Michalowski was already a fan of the Austin, Texas, rock group Spoon, so he programmed the robot to make random combinations of movements in response to the heavy beat in the group's song, "I Turn My Camera On," and that became the video that's been viewed on YouTube.

It became so popular, he said, that Wired magazine paid to produce a professionally directed video showing Dr. Kozima carrying Keepon around Tokyo, dancing to another Spoon tune and interacting with passers-by. Recently, a similar video was completed in Seoul, South Korea, he said.

While Keepon may have a therapeutic role with children, Mr. Michalowski's Ph.D. work is looking at a more fundamental issue: How does movement shape our interactions with each other?

We all need to coordinate our body language with each other to have successful conversations and social contact, Mr. Michalowski noted. "For instance, the frequency with which you nod when someone is talking to you shows whether you understand what someone is saying, and all this turn-taking is a lot like a dance that we're not conscious of all the time, but if you don't do it right," your partner will think you aren't listening or that something is wrong with you.

Ironically, he said, if someone doesn't move in a normal way, such as a person with autism, "you might even call the person robotic, because their timing is not quite right."

Dr. Kozima designed Keepon to be as approachable and unthreatening as possible, and Mr. Michalowski believes that in some ways, it can actually come across as more humanoid by not looking so much like a human being.

"People ask, 'Why don't you give it some arms or a mouth?', but the point is to take away as much as you can. We probably could even take away the nose. It's the bilateral symmetry and the two eyes that are the most important visual cues for movement."

One way of understanding that principle, he said, is to look at successful animated films. His favorite example is two films that came out in 2004 -- "Polar Express" and "The Incredibles."

"Polar Express" tried to make its characters as realistic as possible, while "The Incredibles" used a much more cartoonish approach to its characters.

"These two movies both had the same amount of computing power, the same kind of animators' talent, but one tried to be photorealistic and one tried to be more of a caricature," he said, "and of course, 'The Incredibles' was a much more successful movie."

In the same way, he said, it is actually harder to make a "realistic" robot that people can relate to.

"You can choose to create a very complicated robot face that has a lot of controllable parts," he said, "but if you've got 12 motors, you've got to coordinate to express an emotion just right, that's not only a lot more work but has a much higher risk of failure."

No matter what shape "emotional robots" take in the future, he does not necessarily see them looking like miniature humans.

"Just because we make robots social doesn't mean they have to be humanoid. Keepon shares very little morphologically with a person."

In fact, the last thing he expects is a robot like "Rosie" from "The Jetsons."

"If we look at where household robots are going, it's probably not going to look like a humanoid servant that makes sandwiches and washes dishes and mops the floor. That would be a very inefficient way of accomplishing tasks that would be solved more easily by specialized automation."

First Published: March 2, 2009, 10:00 a.m.