Here is the full transcript of pediatrician and epidemiologist Dimitri Christakis on Media and Children at TEDxRainier conference. To learn more about the speaker, read the speaker bio here.
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Dimitri Christakis – Pediatrician and epidemiologist
I am a pediatrician, a researcher and a parent and I became those things in that order. And the reason the sequencing is important is because even though I was a doctor who took care of children for a while and I was a researcher who studied ways to keep them healthy, it wasn’t until I became a parent that I got interested in, some might even say obsessed with early learning.
It was 14 years ago when my son was born and I took a month paternity leave to be with him in his third month of life. And now in retrospect as a pediatrician I should have known better because I opted for the time when colic crescendos and I spent that month with him and snuggly bouncing on a big blue ball and watching more daytime television than I had in my life and noticed that he was actually interested in and as much as I’d like to believe that my two month old was following CNN as closely as I was, it was obvious to me that he wasn’t, and yet something about that experience was important to him.
Now why do these early experiences matter? The typical newborn brain is 333 grams and in the first two years of life, it actually triples in size, it’s an extraordinary period of brain growth, unparalleled over the life course. And you can see that here — here is brain growth over the lifespan and you can see how steep the rise is early on and it continues to grow until about age 20 and I’ll let you guys in the audience find yourselves over on the right there and see why you have such a hard time finding your car keys this morning.
Now we’re actually born with a lifetime supply of brain cells or neurons, that’s not what actually grows. It’s the connections between those brain cells, we call synapses, that account for that brain growth. And those synapses form based on early experiences. If you will, the mind is fine tuned to the world, the babies and habit and to give you an example of that, that you can all relate to any child born anywhere in the world can learn to speak any language fluently. But if she isn’t exposed to certain sounds early in the first few years of her life, she can learn to speak another language later but she’ll never sound like a native speaker. So baby born today in mainland China as amazing as it is can learn to speak fluent Mandarin but if she doesn’t hear English sounds early in her life she can learn to speak English later but as we all know we know such people, she’ll struggle making certain sounds, it wasn’t because she wasn’t born with that capacity, it was because her early experience didn’t condition her mind to learn them.
Now this graphic actually shows just that. What you see is the brain and you see the neurons and the synapses connecting them. We’re born with about 2,500 synapses; by age 3 we have 15,000 and then over time those connections are actually pruned in response to the external stimulation, the external world that we live in.
And to give you another example of that. This is the breathing pattern of a one-day old infant listening to music. And you can see here that he’s listening to Mozart and then Stravinsky is put on and then Mozart again. Now I show you this not to present some kind of an infantile critique of classical music but — and those of you in the audience who are classic music aficionados might have a hypothesis about why Stravinsky did this to his breathing pattern. But the point is — the point is that even at one day of life there is a discernible physiological reaction to what babies are actually hearing.
Now we know from decades of research that too little stimulation early on is bad for brain development. I show you here two PET scans. Now PET scans are measures of brain function; the brighter colors show more brain activity. And on the left is a PET scan of a normal kindergartener and on the right is a PET scan of a child who was raised in a horribly neglected environment. This is actually a PET scan from a child who was raised in a Romanian orphanage and was profoundly neglected early in life. And you’ll notice that the areas of his brain that show no activity at all, it didn’t develop as a result of too little stimulation.
Now this is a horrific example of too little stimulation and the untoward consequences of it. But the question we’ve had in our lab for some time is: What about too much? Is it actually possible to over-stimulate the developing brain or more appropriately to inappropriately stimulate the developing brain in ways that are actually not beneficial but harmful? And this is important, because we’re technology-izing childhood today in a way that’s unprecedented.
In 1970, the average age at which children began to watch television regularly was four years, like this cute little girl here. And today based on research that we’ve done, it’s four months. It’s not just how early they watch but how much they watch. A typical child before the age of five is watching about four and a half hours of TV a day; that represents as much as 40% of their waking hours, which brings us to Baby Einstein.
Many of you probably have not seen Baby Einstein but I will show you a random 20-second clip from Baby Einstein day on the farm and here it is.
In that 20-second clip, there were seven scene changes, about one every three seconds. It’s about the most exhausting day on the farm since John Steinbeck’s Grapes of Wrath. And of course, it’s nothing like being on a real farm, right? Adults watching this find it discombobulating, because your mind is trying to make a coherent narrative out of this, and there is no coherent narrative. It jumps all over the place. But babies aren’t trying to make a coherent narrative out of it; they’re not capable of doing that. It’s all of that screen change, all of that stimulation that’s keeping them actually engaged in the screen.
So we’ve had for a while, what we call the overstimulation hypothesis, which is that prolonged exposure to this rapid image change during this critical window of brain development would precondition the mind to expect high levels of input, and that would lead to inattention in later life. So you watched enough Baby Einstein day on the farm as a baby and when you go to a farm as a school-age child it’s boring; it’s too slow: how come there’s no sheep suddenly popping into my face? How come there’s no marionette going back and forth? Why do I have to walk from here to there? That’s the general idea that you’re conditioning the mind to that reality which doesn’t actually exist.
And we tested this some years ago and what we found was that the more television children watched before age 3, the more likely they were to actually have attentional problems at school age. Specifically for each hour that they watched before the age of three, their chances of having attentional problems was increased by about 10%. So a child who watched two hours of TV a day before the age of three would be 20% more likely to have attention problems compared to a child who watched none.
Now what else did we find? We found that the more cognitive stimulation children received, and we measure cognitive stimulation in terms of how often parents read to their child, how often they took them to the museum, how often they sang to them, we found that cognitive stimulation reduced the chances of attentional problems later in life. In fact, each hour of cognitive stimulation reduced them by about 30%. So if you will, these are two sides of the same coin. There are certain things that we can do early on in our children’s lives that enhance their ability to pay attention and certain things that we can do early on that actually impede them.