2014 Brain Awareness Night by Dr. Nathan Fox: A Science-Based Framework for Early Childhood Policy
Dr. Nathan Fox, Ph.D.
Distinguished University Professor, University of Maryland
Member, National Scientific Council on the Developing Child
“A Science-Based Framework for Early Childhood Policy”
Thursday, March 21, 2014
Dr. Nathan Fox: Thank you. Good evening. Let me tell you what I’m going to try to do in a very brief period of time. As Bill mentioned to you, I’ve trained as a developmental psychologist and come a little bit later to being a neuroscientist in the sense that I’ve developed methods for brain imaging for infants and children. About 15 years ago I was fortunate to be a member of a working group that was funded by the MacArthur Foundation that combined groups of neuroscientists, the real neuroscientists like Bill over there, who work in the lab or work with rodents, rats or mice or other animals, and study the brain in detail with developmental psychologists. The idea was to - - sorry, can everybody hear me? I don’t need the microphone. The idea was to come up with a common language and also to try and understand what we know about the effects of early experience on the brain.
One of the outgrowths of that MacArthur network was the National Scientific Council on the Developing Child of which I am a member, I have been since its founding, and that is a group, again, of scientists, neuroscientists and developmental psychologists, who are interested in talking to community organizations and to people like yourself and to try and hopefully transmit information about what we know about the brain, brain development and its influence on policy. I’m not a policy person myself, but I live near Washington D.C. so I guess that qualifies a bit.
OK, so let me start by illustrating three core concepts to development. The first is that brain architecture is established early in life and supports lifelong learning, behavior and health, and I’m going to go through all of these in some greater detail. The second is that stable, caring relationships and what we call “serve and return” interaction shape brain architecture. The third is that toxic stress in the early years of life can derail healthy development. Those are the three I’m going to try and get through in the short period of time, those three core concepts and show you what we know about these concepts in terms of the brain and why these are so important.
OK, so let’s start with the first which is experiences build brain architecture. It is a given in terms of people who study the brain and its development that brain architecture supports lifelong learning, behavior and health. Indeed, we know that as infants and then young children and children develop, they are developing alongside their behavioral development, undergirding that behavioral development is brain development. We also know that infants and children are not little adults. They develop over time with skills emerging over time, and like that, their brains are built over time starting in the earliest years.
One way to thinking about brain development is to think about the way we think about skill development, which is that simple skills come first. Before you can learn how to ride a bicycle, you first learn on a tricycle perhaps, and you first learn with training wheels. Then those simple skills merge or morph into more complex skills which are built on top of them. Very similarly, the brain is built that similar way and cognitive, emotional and social capabilities are interstitially intertwined throughout all of this.
It used to be the case, as a psychologist I can attest to this way back in my graduate years, that the way that psychologists approached emotion and cognition were totally separate. The people who studied thinking did not think that they needed to understand emotion and the people who studied emotion studied it really divorced from how it influences the way in which we think. That’s really no longer the case. We now understand in the areas of psychology, both cognitive development, social development, that these are interstitially intertwined and in order to understand one you need to understand the other. You need to understand the way in which emotions affect the development of cognition and you need to understand the development of cognition in order to understand emotion. The final point here is that a strong foundation in the early years improves the odds for positive outcome and a weak foundation increases the odds of later difficulties.
Let’s just look at some figures here that illustrate these issues about brain development. The ability to change brains decreases over time. What do I mean by that? Well, as I’m getting closer to this part of the slide, I can say that what we know about brain plasticity is that the brain is most plastic during the early years of life. What does that mean? It means that in terms of learning, learning new skills, learning new languages, that we have the best abilities and the best plasticity in our brains in order to do that. As we get older, it’s not that we cannot continue to learn, adult learning, and I consider myself on this side of the graph, I hope that I continue to learn and to learn new thing, but my ability to learn complex skills is much harder, that is the ability to learn complex skills is much harder as we get older. That’s because the plasticity in our brains to have that learning simply decreases.
Now, at the same time the effort in order to make those neural connections in order for us to learn increases, so it’s easier, sort of the converse of what I said, it’s easier and the brain is more plastic in the early years of life. It’s more difficult and it takes more effort in order to learn as we get older. All right, so that’s one principle.
The second principle is that neural circuits are wired in a bottom-up sequence. This graph nicely illustrates how the brain changes over the first years of life. You can see these lines represent the increase in synapses in the brain, that is the connections that occur in the brain. You can see that there’s a significant increase in the areas that are underlying vision and hearing, the sensory areas, starting even before birth and over the first months of life. Then you can see that that decreases during the second, third and fourth years of life, and I’ll explain that that decrease means in just a second, but what I want to show you is another curve which shows you that in fact the increase in synapses and the connections that are occurring in the brain for language is shifted a bit over to the right. That’s because it occurs later.
The changes in the brain, the wiring that occurs in the brain for different skills occurs at different times. Here you see the wiring for skills for higher cognitive function, particularly in the prefrontal cortex and what you can see here is that that’s a more protracted and longer period of time during which that wiring can take place and in which the changes in the brain in that wiring are occurring. There you can see what’s happening in the first year of life. I just highlighted that there for you.
Now, why do those curves go up and then go down? Let me illustrate that for you. This is a slice of the prefrontal cortex in the human brain at birth. Those are neurons in the brain, and those long things are the axons, and those spiny things at the end, those are the synapses that are connecting the neurons one to the other, and you can see what it looks like. Now, here’s the same area in the brain at age six. What do you see? You see a proliferation of these neurons, a proliferation of these synapses and these connections that have occurred in the same area of the brain six years later.
Now let’s look at what it looks like at age 14, same area of the brain, and so what you see here is what? That there has been a decrease in those synapses that has occurred over the period of time between 6 and 14 years. Now that decrease has been called lots of things in the neuroscience literature, but you can think about it with the gardening metaphor. In fact, one of the words that’s used in neuroscience literature is pruning. What do you do when you prune? Well, you snip away branches that you no longer need, and that’s exactly what the brain is doing. You can think of this, think about my bicycle metaphor just a second ago. This is what you see here at age six are the training wheels. This is the brain providing scaffolding and support as the child is learning new skills. But as you learn new skills, what happens? So if you’re playing tennis, if you’re riding a bike, what happens? Your skill becomes more automatized. It becomes more automatic and so you don’t need the support, the scaffolding that you needed when you first started learning. That’s what’s happening between 6 and 14 years and that’s what pruning is about. Those different bumps that you saw in the earlier slide are about this blossoming and this pruning of the synapses in the brain that is occurring over time.
OK, now there are two principles of brain development that I wanted to tell you about. This is a neuroscientist by the name William Greenough who, in 1984, published a paper in the Journal of Child Development, so this is a paper for developmental psychologists in which he talked about two types of experience. One type of experience he called experience-expectant. The brain expects to receive certain types of information during a specific period of time. We often call those sensitive periods in brain development.
The other type that he talked about was experience-dependent which is this is when the brain learns new information which is based upon the child’s environment, their culture, the community in which they live in. They learn from the world around them. Now, the experience-expectant type of structures, those are the ones that are involved in vision, in perception, in audition, in language, and to a certain extent also, in terms of the development of social relationships, all incredibly important in the first years of life. The experience-dependent learning occurs also, obviously later, and also throughout life.
OK, interaction shapes brain circuitry. We’ve coined this metaphor called serve and return. I don’t know if any of you are tennis players, I tried my hand at it a number of times, I’m not great, but I do like to watch it. In tennis you have two players, you could have four, but you have two players, one hitting the ball to the other. There’s serve and then there’s return. They hit the ball back and forth to each other. When we talk about the type of social skills and social interaction that we want young children to experience, we talk about it as serve and return.
What we mean by that is that young children naturally reach out for interaction through babbling, facial expressions, gestures, and adults respond in kind. These serve and return interactions going back and forth, the mom and the baby interacting with each other are essential for the development of healthy brain circuits; therefore, the systems that support the quality relationships in early care settings, communities and homes, also support the development of brain architecture. That is, our ability to provide moms and dads with the opportunities to engage in serve and return are critical to allow typical and healthy brain architecture to development.
OK, so what are the barriers to educational achievement that emerge at a very early age? This is from a study that was in 1995 by Hart & Risley and what they did is they recorded the conversations in parents. Well, it’s unfortunate, though, how they labeled them, but this is what they did, college educated working class and what they call welfare parents. What you see here, what I really want to show you here is that at 16 months of age there was no difference in the vocabulary production of the children, but starting at around 16 months of age you get this huge divide, and the divide continues. That’s because the language environment and the language input for children, at least as far as Hart & Risley argued, was more impoverished in the working class and in welfare homes than it was in the college educated homes.
Bill mentioned executive functions and I’m going to say just a few words about it because Dr. Blair [SP] is going to be talking about that, but the metaphor that we use about executive functions is an air traffic control system. We all know who the air traffic controllers are and what they do, so you can think of executive function as a group of skills to help us to focus on multiple streams of information, set goals, make plans, make decisions with available information, revise those plans and resist hasty actions.
We would hope that our air traffic controllers are going to be good at executive function skills because they’re dealing - - I don’t know if you’ve ever seen what it looks like when an air traffic controller is sitting up there with the screen and all of these planes coming in and so forth and so on. They’ve got to be able to coordinate lots of information. They’ve got to resist making hasty actions. They’ve got to set goals and make plans. That’s what it means to have good executive function skills.
Executive function skills are key biological foundation for school readiness as well as outcomes in health and employability. So what are these executive function skills, just very briefly? Inhibitory control, working memory, being able to hold and manipulate information in our heads over a short period of time and cognitive flexibility, the ability to adjust to demands, priorities and perspectives.
Now, what do we know about executive function? This is from a long-term study of a city in New Zealand called Dunedin and what the researchers found is that children who were high in self-control, they had better health outcomes and less substance use than children who had poorer self-control as young children. If you look to see how self-control predicts greater wealth, you can see that greater self-control was associated with greater income as an adult. If you look at socioeconomic status, socioeconomic status was associated with self-control measured in very young children. Finally, what these authors report is that self-control actually predicted crime and delinquency. So individuals who were low on self-control were more likely to have, as adults, criminal convictions compared to those who were low in self-control.
Third point, toxic stress derails healthy development. In our group, our group - - I don’t know how many of you have heard the term toxic stress, now. How many? OK, so a lot of you. I don’t know whether I should admit this or not but it was that group, the National Scientific Council, that coined that term. It came as a result of us trying to figure out how to categorize the different types of stress that individuals undergo, and here’s what we came up with. We came up with these three levels of stress.
The first is to say, is that there are actually periods of time when stress could be positive. It could motivate you. This brief elevation in stress hormone is actually beneficial in terms of motivating people to be able to perform well. So if you’re going in for an exam or if you’re doing something that requires a lot of attention, a small degree of stress is actually pretty good.
The second is tolerable stress, and what we mean by that is actual serious, temporary stress responses, but these can be handled, and that’s the reason we call it tolerable, by supportive relationships. So it is in fact the case that we all experience some stressful event in our lives, but a way in which we deal with those stressful events is by having significant buffering from our significant others, from our wives, from our spouses, from our children, from our families, from our community, if they can provide that support, then that stress is tolerable. In the final, which you’ve heard of, is called tolerable stress, and that is prolonged activation of the stress system in the absence of these protective relationships.
So what do we know about the effects of stress? We know that relationships buffer stress, I told you that, that’s the tolerable stress, and learning how to cope with moderate short-lived stress actually can build a healthy stress system, but toxic stress is when the body’s stress response system is activated excessively, and that actually can weaken brain architecture. The message here is that without caring adults, children who are exposed to tolerable stress for any of the reasons that I have up here, poverty, neglect, abuse, severe maternal depression, this can have long-term consequences on the child and on their developing brain.
Just to show you some data in terms of the magnitude of risk factors and its relationships to negative developmental outcomes, you can see here that there’s actually a cumulative effect of risk factors in terms of developmental delay. We also know that persistent stress can actually change brain architecture. There you see a neuron with all of these dendrites around it, those are the spiny things that I showed you in that earlier figure, and that’s a healthy typical neuron, and there’s the same neuron or the same type of neuron, but after exposure to chronic stress.
Now these studies are done in nonhuman primates and in rodents, but they tell the same story because ultimately we can learn from the neuroscientists about the effects of stress on brain architecture by looking carefully at the neurons and the brain, things that really can’t do in our studies of infants, children and adult humans, so it’s important to know that. There you can see the two different types of neurons and here you can actually see it perhaps a little bit better. You can see the neuron that’s damaged by toxic stress, fewer connections, and there’s the neuron on top there that is healthy with many different connections.
Here’s a figure from a study that we actually did with children who were exposed to significant psychosocial deprivation, and you can see there that on the left that you have heightened brain activity, that’s the red, for children who are raised in typical families and there you see on the right, the brain imaging of children who are raised in extreme neglect. You can see the picture tells a thousand words. It tells you that the brain of these children who have undergone extreme neglect, that the power, that the energy that the brain is emitting is actually turned down, dampened, as a result of exposure to extreme neglect. There, you can see that.
OK, so what can we do? Here’s the policy implications. First of all, effective services can improve relationships and environments. Programs of evaluation research combined with the scientific understanding that I’ve told you about of how children develop, can help us make better decisions about which programs or policies we want to use and want to make smart investments with. Low-cost services that have little impact are basically, in my opinion, a waste of money.
Responsible investment focuses on effective programs that are staffed appropriately, implemented well and improved continuously. Look, if you’re going to do anything, if you’re going to renovate your house, you wouldn’t want to do it on the cheap, so you wouldn’t want to do an intervention program for the lives of young children and their developing brains on the cheap. That’s basically what the message is there.
If you do a cost-benefit analysis, you can see the positive returns of many programs that have been done to look at the effects of early intervention. There’s the Abecedarian project, the Nurse-Family Partnership and the Perry Preschool. Significant returns on the investment, and that should be the message to the business community about the importance of investing in early childhood.
OK, last comments. There are no magic bullets. We all know that. Positive relationships and quality learning experiences can be promoted both at home and through a range of evidence-based parent education, family support, early care and education, and intervention services. We know that. We also know that a balanced approach to emotional, social and cognitive development will best prepare children for success in school and later in the workplace. Folks, I can tell you that before - - this is sort of the dirty secret of the National Scientific Council. The dirty secret is that developmental psychologists, child psychologists and educators have known for years, the effects of poverty, stress, toxic stress, abuse, neglect, on children’s behavior. We’ve known that.
What the National Scientific Council and researchers have now added to that is they have provided the brain mechanisms for understanding exactly how that works. Now, the flip side of that and the good part of that is that what it means is that you can then use that information to design and develop interventions that are based upon the neuroscience, that are based upon this evidence. Those interventions can be successful in promoting healthy development of young children, even young children who are living in conditions of poverty and neglect
The effect and its factors for early care and education programs for children birth to five; qualified and well compensated personal, small group sizes and high adult child ratios, language rich environments, developmentally appropriate curriculum, safe physical setting, warm and responsive adult child interactions. These are the kind of things that young children need. This will build their brains, their brain architecture in a healthy and positive way, and promote the success of the next generation.
Science points towards a two-tiered approach to reducing disparities. Here, I think it’s important that I mention the importance of health services. Basic health services are critical for families and young children, and good quality early care and education can promote healthy development, and early detection of children who have problems. These targeted services for children experiencing tolerable toxic stress can reduce these disruptions in the nervous system and the immune system that would ordinarily lead to later learning behavior and problems.
OK, this is the website for the National Scientific Council on the Developing Child. We’ve been around for about ten years now. Our goal is to provide you with the information about brain development and its role in early childcare and early development. If you go to this website, there are working papers, there are videos and there are educational materials that I recommend for you. I hope that I’ve convinced you a little bit about the importance of this for the health and welfare of young children. Thank you. [applause]
Male Audience Member: [inaudible 00:30:06] very well.
Male Audience Member: Yeah.
Male Audience Member: You were too, though.
Male Audience Member: Questions? Paul, can you handle this? Do we have any questions for Dr. Fox?
Male Audience Member: There’s one right there.
Female Audience Member: Hi, what do you think are kind of the next directions in terms of some of this, the different interventions that they’ve put in? I know Boston has had some great work done with their programs that they’ve put in. It seems like we’ve kind of approached it from a policy angle of being like a top-down, implement the intervention first and then see what our directions are going to be afterwards. Do you think that’s something that is going to continue to happen or is it now going to be something to where we can begin looking at the neuroscience behind what is effective with some of these programs?
Dr. Nathan Fox: Right. Well, I’d like to think that we can do the latter. That is that we can use the neuroscience to inform these interventions. I can say there are two issues, and actually they were discussed at our meeting this afternoon. I think that large-scale interventions are possible, but it’s also possible to have more local micro kind of studies in which you do a smaller evidence-based trial to see if it works in a local area because interventions are terribly difficult to scale up. It may be that we’re at a point now where we should be doing these micro studies and seeing their feasibility and seeing their efficacy. Then once we have a corpus of them and they’re informed by the neuroscience, then we can go from that to the scaling up.
Female Audience Member: I was wondering about with the neuroscience research that’s been happening, is there any critical amount of time that if children are, say, in a childcare setting that’s high quality or if they are in preschool programs that are high quality, is there a certain number of hours per day that if the time spent there is lower in stress can actually reverse some of the damage that might be occurring due to a stressful home life?
Dr. Nathan Fox: That’s a great question and I wish I had a good answer for you. I can tell you what the intuition is. I think, obviously, it’s great if young children have a safe haven and a calm environment in their childcare setting, but they only spend five, six hours a day in that setting and they’re spending more of their time with their families, and their families ultimately are the ones who have the greater influence, not only on their physiology, but on their psychology and their behavior. So yes, I think it’s great to provide that calm and safe and environment for children, but we’ve got to also address the issue of what’s going on in the home.
Male Audience Member: My question goes in exactly the same direction. I was wondering what a realistic program would look like if you have a child that is in an abusive family, lives in a high-crime neighborhood, isn’t the only thing that you would have to do or can do to take the child completely out of that environment? All the points that you listed, and now your answer to this question, points that that seems to be the only thing that would really have long-lasting impact.
Dr. Nathan Fox: I think what communities have to do is they have to get together to provide the supports for families that are in distress like that because, again, I’m not a policy person, but I don’t think that ultimately the solution is taking kids away from their families. I think we’ve got to work to enlarge if you will, the social network of those families and to provide them with the supports and the ability to reduce the stress that they are experiencing in their homes. If we can do that, we can make the environments in which the children are growing up more tolerable.
Male Audience Member: So in reality this is like a generation long process because you would have to reduce the stress in the whole community.
Dr. Nathan Fox: There are ways in which it’s done. For example, I was at a meeting recently in Baltimore where they had a move to success program, in which families actually under a HUD program were able to move to other neighborhoods if they chose to, so that may be one solution. There are multiple solutions, but that may be one solution to allow families to experience a reduction and the stress if they’re living in a high-crime neighborhood.
Male Audience Member: Related to generating evidence-based methods, it seems like one big challenge in this kind of thing is metrics of effectiveness. Do you have any thoughts on ways to shorten the time to evaluate a given approach or are there any evolving ideas on using neuroscience? What kind of methods might allow one to detect the beneficial things early?
Dr. Nathan Fox: Right, I would say a couple things to that. The first is that experimental developmental psychology has, over the last ten years, developed new tasks and new ways of assessment of many of the competencies that I’ve talked about. Let’s take executive function for example, there are a number of people, Dr. Blair included, who have developed new methods and new batteries of tasks which allow for the assessment of executive function in young children. We have the means to be able to probe the effectiveness of certain interventions at a much earlier age. We don’t have to wait until they’re in elementary school for example, in order to see the effectiveness.
Now, it’s always great to be able to see the long-term outcomes and, obviously, we want to know that there’s continued efficacy, but I think we have the skills and abilities now to do that in a shorter time period than we have in the past.
Female Audience Member: In some classic examples of so-called wild children, like Janie [SP] and Victor who had proactively no interaction and very little access to language development, obviously, the interventions for them came way after these critical periods, but do we know at what point interventions need to take place if they can happen after these critical windows of expectant experiences or if they need to happen within so that we can rescue this and get children to where they should be in terms of their peers?
Dr. Nathan Fox: Right, so that’s a great question and requires a really complicated answer, so let me make it short. There are sensitive periods for learning certain skills. Let’s take language. Janie is a good example because she was only found as an adolescent and we know from research that there’s a long period of time for language learning. There’s a great deal of plasticity for language learning and also for second language learning, but it does significantly decrease in the adolescent years, and so the ability to learn even a first language, in the cases that you mention, is significantly impaired and difficult to rescue post a particular period of time.
Now, that said, there’s new and exciting work that’s going on in neuroscience about reemerging or reigniting sensitive periods, particularly in the visual and the auditory, in the perceptual areas. It may in fact be the case that for certain kinds of learning, there will be ways in which you can enhance the plasticity, but generally the plasticity is at the younger ages and not at the older ages.