In The Big Disconnect: Protecting Childhood and Family Relationships in the Digital Age (Aug.) clinical psychologist Catherine Steiner-Adair, writing with Teresa H. Barker, examines how the Internet and new technology are transforming American households.

How does the digital revolution compare to prior moments in history, when families confronted radical changes in the home environment?

What separates this from the advent of the telephone and, later, television is that, back then, parents were still in control of whom their children were talking to and what they were watching. This is the first time that children are talking to complete strangers and watching anything they want.

What sparked the desire to embark on a whole book about this issue?

It was cumulative. I remember seeing a teenage girl having lunch with her mother, and this young girl was on her smartphone... the whole time. During lunch, she and her mother can’t have exchanged more than three sentences. I thought, “Something here is profoundly wrong.” Another time, I watched a mom with her baby in the stroller, paying no attention to anything but her phone. But if there was one moment, perhaps it was [one that I experienced] as a mother. My son is grown now and he’s great, but there was a moment where I really felt that I could be losing him to technology.

Did you notice a change in your work with patients?

Yes. People come to therapy with a range of problems, and technology is not helping. In a contentious divorce, for example, one sees 500 hundred nasty reactive texts in a half-hour. Or [one hears about] a teenage girl’s drama with friends, or with a boyfriend, which is amplified by the texting of really mean-spirited and deeply hurtful things. Vengeful and spiteful feelings have been around forever, but the capacity to express them is now exponentially greater, and the damage is greater.

How worried should we be?

Very worried. But just as parents can say no to TV, they can say no to screens—except for homework. There is absolutely no reason that 8-year-olds need smartphones. Parents must understand that several aspects of their child’s development are at risk. Psychologically, children are losing the ability to reflect. Neurologically, we don’t know the effect of spending hours in front of a screen, but we do know that kids get addicted to stimulation from screens. Some can’t then tolerate the slow pace of reading books. I would say to all parents: if you’re joking about being addicted to your smartphone, why are you handing the addictive thing on to your child?

If there were one piece of advice you could impart to worried new parents, what would it be?

Absolutely [say] no to all screens for a child’s first two years. Everything they need to grow into what they can be is available from their relationship to you and loving caretakers.