By Nick Bilton, New York Times

I recently watched my sister perform an act of magic.

We were sitting in a restaurant, trying to have a conversation, but her children, 4-year-old Willow and 7-year-old Luca, would not stop fighting. The arguments — over a fork, or who had more water in a glass — were unrelenting.

Like a magician quieting a group of children by pulling a rabbit out of a hat, my sister reached into her purse and produced two shiny Apple iPads, handing one to each child. Suddenly, the two were quiet. Eerily so. They sat playing games and watching videos, and we continued with our conversation.

After our meal, as we stuffed the iPads back into their magic storage bag, my sister felt slightly guilty.

“I don’t want to give them the iPads at the dinner table, but if it keeps them occupied for an hour so we can eat in peace, and more importantly not disturb other people in the restaurant, I often just hand it over,” she told me. Then she asked: “Do you think it’s bad for them? I do worry that it is setting them up to think it’s OK to use electronics at the dinner table in the future.”

I did not have an answer, and although some people might have opinions, no one has a true scientific understanding of what the future might hold for a generation raised on portable screens.

“We really don’t know the full neurological effects of these technologies yet,” said Gary Small, director of the Longevity Center at UCLA, and author of “iBrain: Surviving the Technological Alteration of the Modern Mind.” “Children, like adults, vary quite a lot, and some are more sensitive than others to an abundance of screen time.”

But Small says we do know that the brain is highly sensitive to stimuli, like iPads and smartphone screens, and if people spend too much time with one technology, and less time interacting with people like parents at the dinner table, that could hinder the development of certain communications skills.

So will a child who plays with crayons at dinner rather than a coloring application on an iPad be a more socialized person?

Ozlem Ayduk, an associate professor in the Relationships and Social Cognition Lab at UC Berkeley, said children sitting at the dinner table with a print book or crayons were not as engaged with the people around them, either. “There are value-based lessons for children to talk to the people during a meal,” she said. “It’s not so much about the iPad versus nonelectronics.”

Parents who have little choice but to hand over their iPad can at least control what a child does on those devices.

A report published last week by the Millennium Cohort Study, a long-term study group in Britain that has been following 19,000 children born in 2000 and 2001, found that those who watched more than three hours of television, videos or DVDs a day had a higher chance of conduct problems, emotional symptoms and relationship problems by the time they were 7 than children who did not. The study, of a sample of 11,000 children, found that children who played video games — often age-appropriate games — for the same amount of time did not show any signs of negative behavioral changes by the same age.

Which brings us back to the dinner table with my niece and nephew. While they sat happily staring into those shiny screens, they were not engaged in any type of conversation, or staring off into space thinking, as my sister and I did as children when our parents were talking. And that is where the risks are apparent.

“Conversations with each other are the way children learn to have conversations with themselves, and learn how to be alone,” said Sherry Turkle, a professor of science, technology and society at the Massachusetts Institute of Technology, and author of the book “Alone Together: Why We Expect More From Technology and Less From Each Other.” “Learning about solitude and being alone is the bedrock of early development, and you don’t want your kids to miss out on that because you’re pacifying them with a device.”

Turkle has interviewed parents, teenagers and children about the use of gadgets during early development, and says she fears that children who do not learn real interactions, which often have flaws and imperfections, will come to know a world where perfect, shiny screens give them a false sense of intimacy without risk.

And they need to be able to think independently of a device. “They need to be able to explore their imagination. To be able to gather themselves and know who they are. So someday they can form a relationship with another person without a panic of being alone,” she said. “If you don’t teach your children to be alone, they’ll only know how to be lonely.”