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The National Institute of Mental Health archives materials that are over 4 years old and no longer being updated. The content on this page is provided for historical reference purposes only and may not reflect current knowledge or information.

Development of the Young Brain

For more than twenty years, National Institute of Mental Health neuroscientist Dr. Jay Giedd has studied the development of the adolescent brain. Decades of imaging work have led to remarkable insight and a more than a few surprises.


Announcer: Parents and caregivers have always been fascinated with the development of children- their physical and intellectual growth. Studying the development of the adolescent brain has been the life work of National Institute of Mental Health researcher Dr. Jay Giedd.

Dr. Giedd: At different ages of life certain parts of the brain have much more dynamic growth than at other times. And so for very early in life we have our five senses where our visual system and audio system is getting established and optimized for the world around us. In adolescents, the key changes are in the frontal part of the brain involved in controlling our impulses, long range planning, judgment, decision making.

Announcer: Imaging has shown by the time children reach the first grade the physical size of the brain is nearly complete. But what goes on within the brain is nothing short of remarkable.

Dr. Giedd: The brain can grow extra connections sort of like branches, twigs and roots to use a gardening metaphor and then after it has these connections there’s also another gardening metaphor called pruning or cutting back or eliminating the excess or unused connections. And it’s this process of overproducing and then having fierce competition amongst all these connections to see which ones are most useful and which are most helpful for us to adapt to the environment.

Announcer: Our brains have been challenged by the effects of multi-tasking in many ways brought on by the age of social media and use of computer gadgets.

Dr. Giedd: The way that we get information, entertain ourselves and interact with each other has changed more in the last ten years than in the previous five hundred- since Gutenberg’s introduction of the printing press. And so these changes are a real challenge for researchers because they happen so rapidly. So, that adolescents today average about eleven and a half hours of media time. And this is up from six and a half hours just five years ago so that the activities of children and teens has been changing so much. We’ve been challenged- how do we keep up with the changing world and how do we assess the impact for good or for bad on the developing brain.

Announcer: So how well are our children handing multi-tasking in a digital age that changes, seemingly, by the hour? Early evidence suggests -pretty well. In fact, the human brain has a track record of successfully adapting to challenges it wasn’t initially designed to take on- such as reading.

Dr. Giedd: It’s sobering to realize most humans that have lived and died have never read. And so, we’ve been able to change what our brain does based on having the written word and having this environment. And so now the questions is will we be able to change to keep up with the new flood of information coming from all kinds of sources. And up until now the human brain has done a great job of changing- adapting to these environments but there are limitations to this capacity. And so it will be very interesting to see that these so-called digital natives… the children that have grow up never not knowing the multimedia devices… whether their brains will be able to adapt differently than older people.

Announcer: So, what was the human brain originally developed to do? Well, Dr. Giedd says our brains are fundamentally designed to learn through example.

Dr. Giedd: This learning by example is very powerful and that parents are teaching even when they don’t realize they are teaching just by how they handle everyday aspects of their life. How they treat each other as spouses. How they talk about work. When they get stuck in traffic. How they manage their time and their emotions. And this is how most of the teaching is done. It’s not when you set down at these special moments and have a conversation- it’s the everyday moments that really have a huge impact on how the brain forms and adapts.

Announcer: Through the work of Dr. Giedd and his colleagues, we’ve learned so much about the development of the adolescent brain. But researchers like Dr. Giedd may be entering a new golden age of research… as these so-called “digital natives” lead us to new findings in the ever-evolving childhood brain.