WASHINGTON • Kids adore their new robot siblings.

As millions of American families buy robotic voice assistants to turn off lights, order pizzas and fetch movie times, children are eagerly co-opting the gadgets to settle dinner table disputes, answer homework questions and entertain friends at sleepover parties.

Many parents have been startled and intrigued by the way these disembodied, know-it-all voices - Amazon's Alexa, Google Home, Microsoft's Cortana - are impacting their kids' behaviour, making them more curious, but also, at times, far less polite.

In just two years, the promise of the technology has already exceeded the marketing come-ons.

The disabled are using voice assistants to control their homes, order groceries and listen to books. Caregivers to the elderly say the devices help with dementia, reminding users what day it is or when to take medicine.

For children, the potential for transformative interactions are just as dramatic - at home and in classrooms. But psychologists, technologists and linguists are only beginning to ponder the possible perils of surrounding kids with artificial intelligence, particularly as they traverse important stages of social and language development.

"How they react and treat this non-human entity is, to me, the biggest question," said psychologist Sandra Calvert, director of the Children's Digital Media Center. "And how does that subsequently affect family dynamics and social interactions with other people?"

With an estimated 25 million voice assistants expected to sell this year at US$40 (S$57) to US$180 each - up from 1.7 million in 2015 - there are even ramifications for the diaper crowd.

Toy giant Mattel recently announced the birth of Aristotle, a home baby monitor launching this summer that "comforts, teaches and entertains" using artificial intelligence from Microsoft.

As children get older, it can ask or answer questions. The company says: "Aristotle was specifically designed to grow up with a child."

Boosters of the technology say kids typically learn to acquire information using the prevailing technology of the moment - from the library card catalogue to Google to brief conversations with friendly, all-knowing voices.

But what if these gadgets lead children, whose faces are already glued to screens, further away from situations where they learn important interpersonal skills?

It is unclear whether any of the companies involved are even paying attention to this issue.

Amazon did not return a request for comment.

A spokesman for the Partnership for AI, a new organisation that includes Google, Amazon, Microsoft and other companies working on voice assistants, said nobody was available to answer questions.

"These devices don't have emotional intelligence," said Professor Allison Druin from University of Maryland, who studies how children use technology.

"They have factual intelligence."

Children certainly enjoy the company of these devices, referring to Alexa like another family member.

"We like to ask her a lot of really random things," said Emerson Labovich, a fifth-grader, who pesters Alexa with her older brother Asher.

This winter, Emerson asked her almost every day for help to count down the days to a trip to The Wizarding World of Harry Potter in Florida.

"She can also rap and rhyme," Emerson said.

Today's children will be shaped by AI much like their grandparents were shaped by new devices called television. But you could not talk with a television.

Mr Ken Yarmosh, a 36-year-old Northern Virginia app developer and founder of Savvy Apps, has multiple voice assistants at home, including those made by Google and Amazon.

His five-year-old son, in comparing his two assistants, came to believe Google knew him better.

"Alexa isn't smart enough for me," he would say, asking random questions that his parents could not answer, like how many miles it is to China.

In 2012, University of Washington researchers published results of a study involving 90 children interacting with a life-size robot named Robovie.

Most kids thought Robovie had "mental states" and was a "social being". When Robovie was shoved into a closet, more than half felt it was not fair.

A similar emotional connection is taking hold with Alexa and other assistants - even for parents.

"It's definitely become part of our lives," said Emerson's mother, Mrs Laura Labovich, who then quickly corrected herself: "She's definitely part of our lives."

The problem, Prof Druin said, is that this emotional connection sets up expectations for children that devices cannot or were not designed to meet, causing confusion, frustration and even changes in the way kids talk or interact with adults.

And then there is the potential rewiring of adult-child communication.

Although Mattel's new assistant will have a setting forcing children to say "please" when asking for information, the assistants made by Google, Amazon and others are designed so users can quickly - and bluntly - ask questions.

Parents are noticing some not-so- subtle changes in their children.

To ask Alexa a question, all you need to do is say her name, followed by the query. No "please" and no "thank you" before asking a follow- up question.

"Cognitively, I'm not sure a kid gets why you can boss Alexa around, but not a person," California venture capitalist Hunter Walk wrote in a blog post of his four-year-old daughter.

"At the very least, it creates patterns and reinforcement that, so long as your diction is good, you can get what you want without niceties."

The personal yet transactional nature of the relationship is appealing to children and teenagers. Parents have noticed that queries previously made to adults are shifting to assistants, particularly for homework - spelling words, simple maths, historical facts.

Upside: No more fights over what the temperature will really be and what is appropriate to wear.

Downside: Kids will go to their parents less, with both sides losing out on time-worn interactions.

Professor Kate Darling from Massachusetts Institute of Technology, who studies how humans interact with robots, said: "There can be a lot of unintended consequences to interactions with these devices that mimic conversation. We don't know what all of them are yet."

But most researchers, educators and parents - even some kids - already agree that these devices need to be put in their place.

Ms Gwyneth Jones, a librarian who uses Amazon's device at Murray Hill Middle School, puts Alexa away for a couple of weeks at a time, so students do not rely on it too much.

Mr Yarmosh is keeping the assistants out of his children's rooms.

Emerson and her brother take a school playground approach. "Alexa," they'll say, "you're such a butt."

WASHINGTON POST