A fun animation about the development of tamariki and rangatahi brains by the NZ Classification Office in collaboration with youth health expert Dame Sue Bagshaw.
Source: New Zealand Classification Office
Key points about adolescent brain development
- a safe environment where rangatahi (young people) have consistent, loving support is vital for the brain to develop well
- when you are talking to rangatahi, be careful to check what emotion they are seeing in you
- always acknowledge your child's emotions first and then help them to think about what they are feeling
- rangatahi need adults to believe in them and encourage them
- rangatahi respond better to rewards than to punishment
- rangatahi need clear, consistent boundaries
- very importantly, you need to respect their growing capacity and ability to do things independently
When brain development happens
The brain develops very rapidly in the first 3 to 5 years of life, and all the structures and building blocks are present by the age of 9. The different centres of the brain develop and become functionally connected over time. The last part to mature is the prefrontal lobe. This happens during adolescence.
Many things affect brain development including genes, individual and environmental factors.
This illustration shows a side view of the brain in a young person, with key areas of the brain labelled.
Source: KidsHealth
transcribeTranscript
This illustration shows a side-view drawing of a young person’s head with the brain shown in cross-section. The following brain areas are coloured and labelled:
- Prefrontal cortex (front of the brain)
- Amygdala (small, deep area near the centre)
- Hippocampus (curved area in the centre of the brain)
- Cortex (outer layer of the brain)
- Cerebellum (rounded area at the lower back of the brain)
- Spinal cord (stem running down from the brain)
The labels are connected to each brain area with straight black lines.
At the top right is the KidsHealth logo with the website: kidshealth.org.nz.
Why the brain takes so long to develop
Human beings are the only animals that are born completely helpless, and we have the biggest size of adult brain. It is believed that if we were born with an adult-sized brain, our heads would not fit through our mothers' hips. Brain development that continues after birth also helps us better adapt to our living environment (whether it be a city or rainforest) and thereby increases our chances of survival.
We used to think that once children had gone through puberty and growth had finished, development was complete. Then, MRI scanners were invented, and they showed that the brain continues to change for a long time after puberty has finished. In fact, brain development may not be complete until nearly 30 years of age.
The following image shows that the brain doesn't change much in size between 5 and 20 years of age. What changes is the colour. The blue colour shows all the connections happening between all the parts of the brain that are already formed.
This illustration shows brain scans from ages 5 to 20. The colours show how it develops and matures over time.
Source: Copyright 2004 - National Academy of Sciences, U.S.A.
transcribeTranscript
A series of 10 brain scan images arranged in two rows, showing brain development from age 5 to 20. Each column shows two views of the same brain:
- The top row shows the right-side (lateral) view
- The bottom row shows the top-down view
A red diagonal arrow across the image is labelled 'Age', with 5 at the left end and 20 at the right.
Each brain is coloured using a heatmap that represents the amount of grey matter (GM) across the brain’s surface. The colour bar on the right shows GM volume, with red and yellow representing higher grey matter and blue/purple representing lower grey matter.
This image sequence shows how the brain changes from age 5 to 20. While the size of the brain stays similar, the colours shift from red/yellow/green to blue—showing how the brain matures over time. This process is called grey matter maturation.
How the brain develops
Some people like to think of the brain in 4 parts.
1. The spinal cord and the base of the brain
Delivers messages to and from all parts of the body.
Controls what happens in the parts you don't have to consciously think about like the heart, lungs and stomach.
This illustration shows the adolescent brain in cross-section with the spinal cord highlighted.
Source: KidsHealth
transcribeTranscript
A side-view illustration of a young person’s head, with the brain shown in cross-section. The spinal cord is highlighted in light yellow and runs down from the base of the brain into the neck and spine. A black line points to it, with a label that says 'Spinal cord'.
The rest of the brain is shown in greyscale with detailed folds and internal structures, including the cerebellum.
At the top right is the KidsHealth logo with the website: kidshealth.org.nz.
2. The cerebellum
Controls and coordinates movement and other brain processes.
This illustration shows the adolescent brain in cross-section with the cerebellum highlighted.
Source: KidsHealth
transcribeTranscript
A side-view illustration of a young person’s head with the brain shown in cross-section. The cerebellum is shaded brown and located at the lower back part of the brain. A black line points to it with the label 'Cerebellum'.
The rest of the brain is shown in greyscale with detailed folds and structures.
At the top right is the KidsHealth logo with the website: kidshealth.org.nz.
3. The amygdala and hippocampus
Controls emotion and memory.
This illustration shows the adolescent brain in cross-section with the amygdala and hippocampus highlighted.
Source: KidsHealth
transcribeTranscript
A side-view illustration of a young person’s head with the brain shown in cross-section. Two areas in the centre of the brain are coloured and labelled:
- The amygdala is a small circular structure near the front of the brain, shown in light pink and labelled 'Amygdala'.
- The hippocampus is a long, curved structure shown in orange, stretching towards the back of the brain and labelled 'Hippocampus'.
The rest of the brain is drawn in greyscale with detailed folds and internal structures.
At the top right is the KidsHealth logo with the website: kidshealth.org.nz.
4. The cortex
Connects up all the senses and thinking parts, including the prefrontal cortex which is involved in fine judgement and control.
This illustration shows the adolescent brain in cross-section with the cortex and prefrontal cortex highlighted.
Source: KidsHealth
transcribeTranscript
A side-view illustration of a young person’s head with the brain shown in cross-section. The outer layer of the brain is shaded pink to show the cortex, with the front part highlighted more specifically as the prefrontal cortex.
Two black lines point to these areas with the labels:
- 'Prefrontal cortex' – located at the front of the brain.
- 'Cortex' – the outer surface covering the rest of the brain.
The inner parts of the brain are shown in greyscale with detailed folds and internal structures.
At the top right is the KidsHealth logo with the website: kidshealth.org.nz.
Brain development
The brain is thought to develop and connect functionally in stages. The emotional areas of the brain (the limbic system) are present at birth. Regulation of emotions moves from being more of a shared responsibility (with parents) in childhood, to an individual responsibility in adolescence. This process requires new connections to be formed between the cortical (or higher-level thinking) and emotional areas of the brain. It also leads to adult-level decision making, planning and thinking.
Which part of their brain teenagers use most of the time
Rangatahi often 'think with their feelings'
Experiments have been done that show rangatahi often 'think with their feelings'. Scans of the brain can be done to show different parts light up when they are being used.
When adults and rangatahi look at faces showing different emotions, the part of their brain that lights up is different.
Adult brain
Adults use their prefrontal cortex to look at faces and try to decide what emotion is happening.
This illustration shows the brain with the prefrontal cortex highlighted.
Source: KidsHealth
transcribeTranscript
A side-view diagram of the brain with the front section shaded pink and labelled 'Prefrontal cortex'. The rest of the brain is drawn in soft greyscale, showing curved brain folds and inner brain structures.
At the bottom left is the KidsHealth logo with the website: kidshealth.org.nz.
Teenage brain
Rangatahi use their amygdala rather than their prefrontal cortex most of the time. In other words, they are using their emotions to try and understand emotion.
This illustration shows the brain with the amygdala highlighted.
Source: KidsHealth
transcribeTranscript
This illustartion shows a side-view diagram of the brain with a small almond-shaped area near the centre coloured pink and labelled 'Amygdala'. The rest of the brain is drawn in soft greyscale, including visible brain folds and structures.
At the bottom left is the KidsHealth logo with the website: kidshealth.org.nz.
It helps if adults can understand how this feels for rangatahi
To understand how this feels, imagine you have lost your keys and you are already late for work. Think about how many times you look for the keys in the same place - maybe 5, 10, or even 20 times. You panic – you no longer think with your cortex, you are thinking with your emotions.
Remember how it feels if someone tells you to calm down and think sensibly about when you last had them. That is how your teenager feels when they are running on their emotions because their brain often hasn't developed that linkage.
When talking to rangatahi, be careful to check what emotion they are seeing in you
Often, rangatahi can misinterpret emotions, and they see anger when, in reality, you are feeling anxious. This can often lead to many moments of miscommunication. So, when you are talking to rangatahi, be careful to check what emotion they are seeing in you. Make sure you always acknowledge their emotions first and then help them to be able to think about what they are feeling.
What can help brain development
Talking to your child really helps
Adults who talk to tamariki as they're growing up really help. A safe environment where they have consistent, loving support is vital for the brain to develop well. Rangatahi need adults to believe in them and encourage them.
Rangatahi respond better to rewards than to punishment. They need clear, consistent boundaries, and very importantly, their growing capacity and ability to do things independently needs to be respected.
Rangatahi need opportunities to grow many different skills
As their brains grow and get more functionally connected, and as they mature in other ways, rangatahi need to learn that they don't have to be dependent on their parents but can become healthily dependent on other adults. They need opportunities to grow many different skills and to contribute those skills in a way that is valued. The brain develops in a way that produces lots of connections that are then removed if they are not used. So, take care to encourage lots of useful connections.
Develop good habits during the teen years
Another principle is that when connections 'fire together, they wire together'. The teen years are a vital time to develop good habits around activities like thinking positively, eating and exercising as that wires together for adulthood.
We know that the brain can change throughout life but it is much easier to get the 'wiring right during early life and adolescence than during adulthood.
What harms brain development
Abuse of any sort
It is now well established that if tamariki experience any sort of abuse, especially in the early years of life, it can affect how the brain is wired and functions. Types of abuse include:
- verbal
- emotional
- physical
- sexual
- neglect
Sometimes, this is hard to change, so it is very important to protect tamariki throughout their development. This is especially important during times of peak brain development. Peak brain development occurs during pregnancy, the first five years of life, and the second phase of brain development around puberty.
Alcohol and drugs
Read and watch videos about adolescent brain development and the effect of alcohol and drugs on the developing teenage brain.
Parenting Teens - When Should I Talk To My Child About Drugs?
Acknowledgements
Illustrations by Dr Greta File. Property of KidsHealth.
Image - Figure 3 from article 'Dynamic mapping of human cortical development during childhood through early adulthood'. Volume 101, issue 21. Copyright 2004. National Academy of Sciences, U.S.A.
Our grateful thanks to the National Academy of Sciences, U.S.A. for permission to reproduce the image on this page. Please note this image is copyright and requests to reproduce it elsewhere must be made to the copyright holder.
