Doidge: They overenmesh and disconnect at the same time. A few years ago, I was at a lecture with clinicians, discussing visual changes, and a preschool teacher there observed that, increasingly, kids weren't looking at other people when speaking with them. Another teacher there reported the same loss of eye contact. At first it seemed to them like these kids might have Asperger's, which is on the rise, and involves a discomfort with eye contact. But as the teachers watched the parents picking those kids up, they saw they were constantly on their smartphones, not looking at their kids – or the teachers, either, for that matter. As cute as these people's own kids were, in the moment, the kids couldn't compete with an entire virtual reality engineered to keep their parents distracted.

Balsillie: Were they imitating their parents' bad manners, or is it something deeper?

Doidge: Possibly deeper. A big brain task of the first two years of life is wiring up the right hemisphere modules that allow us to read other people's faces to learn about their emotions and, in turn, about our own. This is learned by the rapid-fire exchange of glances between infant and mother when there is so much holding and leisurely gazing into each other's eyes. You know, baby swallows milk, grimaces, mother sees it and unconsciously makes the same face back – she mirrors the baby – showing the baby the distress it is expressing, then sweetly says, "There, there, honey, the milk went down the wrong passage, you're upset in your tummy, let me burp you. You'll feel better." Now, that feeding interaction does more than soothe the baby. It actually teaches the baby about emotions, and that facial expressions show emotions, and ultimately that you can read the internal states of others. That is how we learn about other minds. The same happens when a baby smiles: A healthy adult can't not smile back. You need thousands of those exchanges to develop that emotion-reading right hemisphere, and these exchanges, when they happen, occur very fast. If you are not paying close attention, you miss the baby's smile, or grimace, and your face won't mirror the right emotion back. Good studies show that when the parent doesn't mirror in real time, the baby gets extremely anxious, and if the face is "still" when it should move, babies actually freak out.

Balsillie: So, if parents are distracted, either by a screen or even waiting for a message – i.e., they are multitasking – and not giving the undivided attention required to wire up the brain in this period, you can't do it to your full potential. Because humans are born without a fully developed right hemisphere and we need parents to complete our development, right?

Doidge: Exactly. In brain terms, infants need people bonded to them so closely that they make the requisite sacrifices of attention . My fear is that we are slipping into a new kind of split-attentional-neglect, in a critical period of brain development, because increasingly parents, although physically present, are psychologically online. A large University of Texas at Austin study shows that even having a phone that is off within reach lowers your cognitive capacity, because it still steals your attention. You're so wired into it. If living in virtual reality means living in something that is a simulacrum of reality, we might say that we, by being psychologically online, are making ourselves into virtual parents.

Balsillie: Being mindful of these effects and limiting screen time definitely helps.

Doidge: Definitely, but only partially. Even if you limit your child's screen time to what you think is high-level educational television, if their school is pushing computers and pushing down attention spans, that is way more important than a hundred hours of Sesame Street. McLuhan's whole point was the medium is the message, meaning it isn't the content of the medium – Sesame Street – or even the time spent on it, but the way the medium sculpts the brains of an entire society, and now, the planet. Media gurus in our time are merely mouthfuls of praise for what high tech will do for you – and silent on what they will take away.

Balsillie: So when it comes to the brain, it's basically use-it-or-lose-it?

Doidge: Correct. McLuhan said that each medium can "step up" one sense and step down another. This has huge consequences. Reading books stepped up sight and created a linear habit of mind that valued logic: You go down the page line by line, then turn to the next. This gave rise to a habit of thinking in terms of logical progression of argument. The logician asks of any statement in an argument or conversation, "Does this follow?" But in the digital age, linearity is stepped down. We now ask, "Does it grab you?" Because now information comes at us from many competing directions all at once. Our so-called "great communicators" are those who can best distract us from all the other distractions. When you leave linearity and logic behind, life becomes a Twitter feed: a series of hyper-emotional non sequiturs. That's manifest in our deteriorating, increasingly ignorant public discourse. It's no accident that our education system – itself desperately FOMO – is both computer-crazy and in favour of dropping history, a linear discipline par excellence. That is exactly the wrong move. What we need are schools that teach what screens can't do – to immunize students from the medium's faults. They should get back to teaching the most important books ever written. But that's not enough. Jim. Where are the various levels of government on all these issues?