The Adolescent Brain: What Stays? What Goes?

The brain is a powerful and mysterious thing!  It is functioning all of the time, day and night.   Certain parts of the brain even have multiple pathways to perform the same task……just in case something goes wrong.   There is an entire body of science looking exclusively at what our brain does when we are sleeping.  Another body of science examines how the brain changes during childhood, adolescence, and adulthood. And another body of science looks at how brain activity is linked to social behavior.  In fact, one of the most fascinating developments in social science research is that we now have empirical evidence to explain actual behavior. For example, there is evidence that certain areas of the brain develop 3 years slower for those diagnosed with ADD than for those without ADD.

Some have said that we only use 10% of our brain.  This is a myth that was perpetuated out of the work of Karl Lashley in the 1920s and 1930s. He found that when sections of a rat’s brain were removed, the rat would relearn certain tasks.   Now we know that the removal of even small areas of the human brain can have devastating effects on behavior.  It is more likely that we use 100% of our brain, but only use portions of the brain at any given time.

As you can tell from the pictures above,  the number of synapses decrease between 6 and 14 years of age.  We call this the “Use It or Lose It” phenomenon.  Here’s the way it works.  At 1-year of age, the human brain has twice as many synapses than an adult brain. This is because the brain produces many more connections among cells than it will use.  The developmental task of the childhood years is to prune and select the most useful, or perhaps the most used neurons, synapses, and dendrites. This pruning continues into the early teen years. The important thing to notice is that more is not better.  Think about all the different ways you can go from one location in town to your house.  Maybe you tried several different paths when you first moved into your house. However, over time you learned that one route was faster than all the others. From that point on, you always used the same route. This is exactly what is going on in the teenage brain.  Overtime, your teen’s brain gets more efficient by establishing the best, most direct pathways and getting rid of the others.

There are other changes taking place in the teenage brain besides pruning. Research from Temple University highlights a few other ways the adolescent brain is changing:

• Brain structure – certain parts of the brain are smaller in childhood than in adolescence, while others are larger.
• Brain junction – adolescents use different parts of the brain than children to perform the same task.
• Interconnections – various regions of the brain establish good communication with other regions. For example, the regions responsible for logical reasoning become better connected to those responsible for emotion. When this happens, the two regions talk to one another, allowing for better self-regulation.
• Response to peers – peers activate the reward center of the adolescent brain. That means that teens are more likely to take risks in the presence of their friends, especially when they believe their friends will reward them for their choices. Interestingly, they have not found these same connections when teens interact with adults.

As a parent, you can expect your teen to:

• Be inconsistent.  Outside of the fact that they are trying new things on, different parts of their brain are in different developmental stages.
• Learn from his/her experiences.  Thinking ahead and controlling impulses improves by having exposure to a variety of experiences.  Discussion around why the world works the way it does is also important.
• Need practice – Encourage your teen to plan, anticipate consequences, and regulate behavior.  Practice with your teen whenever you get a chance.  It will not work all the time, but it will work sometimes.  
• Get emotional – Because the teenage brain floods the body with dopamine, teens often respond more quickly to things that spark emotions (like a friend in need) than they respond to less emotional things (like a math test). This doesn’t mean you should let your teen spend his/her entire evening with friends instead of studying.  However, it does highlight the importance of acknowledge your teen’s feelings and allowing him/her to express emotion. It is easier for teens to move onto other things after they have dealt with their emotions.