Robot toys are a Christmas favourite. They are also the testing ground for sophisticated tools that will change our lives, writes Tim Cornwell.

In 1997, researchers at the Massachusetts company iRobot set out to bring alive the dream of many a little girl: a doll that behaves like a real baby. They did their job well - too well. Their prototype robot doll, Baby IT or Bit, "was as much like a baby as we could possibly make," says Jonathan Stein, the project's chief designer. "It would cry when it felt like crying, when it was irritable or got hungry or wet, and, unless you did the right thing, it would not necessarily be satisfied."

It was no surprise that Bit was annoyingly human: iRobot's founder is Rodney Brooks, the Australian-born mathematician who now occupies a revered position in robotics research as head of the artificial intelligence lab at the Massachusetts Institute of Technology. Many of iRobot's top talent, such as Stein, are products of the MIT hothouse.

But although Bit was a remarkable little robot, as a toy it was a no-go. It was more like infant simulator dolls used to show teenagers just how tiresome a baby can be. Bit was too much like a baby, says Brooks - which is often "something you don't want unless it is your own flesh and blood".

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The first toy company to show interest in iRobot's research passed on the project after deciding that Bit would never be a cuddly friend to American children. But toy giant Hasbro took up the reins. The result is My Real Baby, which went on sale in the United States this month priced at just under $100 (?68). It is one of a flood of robot toys hitting the shops for Christmas.

On a toy shop shelf, My Real Baby might look like just another piece of moulded plastic claiming to do all the things that babies do: coo, cry and wee. But she is sold with a promise of 15 "human-like emotions": four different stages of laughter and three different stages of excitement. With seven different simulated facial muscle groups, she promises "hundreds of expressions", from smile to yawn. She has sensors for motion, light and touch. While it is difficult to separate hype from fact, she is described as one of the most sophisticated robots ever to meet the mass market.

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My Real Baby cannot see, or feel with her hands, but tickle her feet and she will giggle, and then giggle louder, her makers promise. If she cries, you can bounce her on your knee. If you rock her to sleep, her eyes will get heavy. She progresses over time from simple words to sentences such as "I want baba please" and "night, night".

Awesomely independent robots are common in science fiction, but the domestic robot has yet to creep, walk or roll its way into even the most modern home. Robot lawnmowers are on the market, and robot vacuum cleaners on the way, but they are inefficient and expensive and, like the electric car, still seem ahead of their time. My Real Baby, according to Brooks, is a harbinger of better things to come.

At MIT, Brooks has helped develop some of the most sophisticated interactive robots in the world, the famous "Cog" and "Kismet". At iRobot, he oversees the making of oil-drilling robots and reconnaissance robots for Nasa and the Pentagon, but he flatly rejects the notion that children's dolls are beneath his dignity. "We are trying to get robots out into the world," he says. "The trick is working out where we can do that, and the toy is one of those areas."

Brooks believes robots are now on a par with the early days of computers in the home, and "toys are a very good place to start," he says. "They are low-cost, they don't come across as robots, they come across as toys and they don't have to be 100 per cent reliable, in the sense that something that is doing some real work for you has to work every time. There is some forgiveness with toys.

"If My Real Baby doesn't catch on that it is being bounced up and down on someone's knee for 5-10 seconds, it is not a disaster. If we have a robot in the home that does not stop but falls down the stairs, that could be a disaster."

Robots are all the rage in the US - and the United Kingdom. Perhaps the catalyst for the notion of a low-cost, seemingly interactive robotic character was the chattering, ear-wiggling Furby, but a key reason for the new craze is Sony's Aibo robot dog, which last year sold out on its limited sales run in both Japan and the US, despite its $2,500 price tag. With a powerful processor, 18 motors and camera vision, Aibo sits, begs, pretends to lift its leg and, with the right software, can play soccer.

There is now a host of metallic robodogs, cheaper imitations with a fraction of the computer power but playing off Aibo's lead, on the US and UK markets.

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The reverberations have been felt in robotics centres at US universities, where toy companies have come flocking for innovation, technical help and the "robot" imprimatur. The Carnegie Mellon University Robotics Institute - with MIT, probably the best known in the US - was besieged by the media when it launched a robot kit for the Palm Pilot, the hugely popular personal digital assistant. For a couple of hundred dollars, the kit uses the Palm's computing power to drive a self-propelled three-wheel robot that can "see" up to about a metre away, an apparently irresistible toy.

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My Real Baby is not the only robot doll on the market. My Dream Baby, from MGA Entertainment, offers a doll with voice-recognition technology and the ability to grow four inches, becoming a toddler that can walk. Furby's co-inventor is bringing out another artificial infant, Miracle Moves Baby.

Opinions on the merits of these living dolls are mixed. Illah Nourbakhsh, who runs the Toy Robots Initiative at CMU, is not totally upbeat. "Want to have tea with your doll?" he asks. "That works pretty well with a fake doll. It does not work very well with a robotic doll. They cannot pick up the tea."

However, Ralph Osterhout, founder of the Osterhout Design Group in San Francisco, which designs and develops high-tech toys, says: "Moving, realistic babies are here to stay. Ultimately, dolls are all going to have assignable personalities, assignable voices, they will be able to communicate with you, with each other, and with other dolls in the world." He predicts: "You are going to be able to have remarkably realistic conversations with a doll within the year."

There is, by most accounts, quite a clash of cultures when toy manufacturers meet robot scientists. The rule of thumb for a toy in the US is that it is made, typically in Asia, for about a quarter of the purchase price. "The average toy retails for $20, and has left Hong Kong with a price of $5, and that means the material content has to be not more than $3.75," Osterhout says. "We are talking 18 cent microprocessors and 12 cent speakers and a printed circuit board that costs 25 cents." Cutting-edge robotics is out of the question.

It was Hasbro that brought iRobot face to face with the toy business culture. In My Real Baby, resources were squeezed to a minimum. "People said we cannot have that sensor, it is too expensive. That cost half a penny. When you add the half pennies, you get real numbers," says Brooks.

Where Bit had five motors, My Real Baby has one. With actuation levers in a cam system inside, it pulls her thermoplastic elastomer face - a flexible skin-like material - into a yawn or a smile, with a slight whirring noise. One early blueprint called for moving arms and legs, but the doll's motion is now only in her face.

"We decided that her face was more important," says Stein. "It is more difficult to snuggle with something that has actuation in her limbs. If you really want a full-service doll, something you can treat as your own child, you want to be able to take it to bed, and not wake up, so it is not knobby and uncomfortable."

My Real Baby weighs 1.4kg, fully loaded with six AA batteries, and is about 46cm long. Stein says it is hard to get over to children how sophisticated My Real Baby is. "You havesensors that you've never seenin toys before. She can sense the lightest touch of yourfinger. She has the beginnings of a central nervous system."

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