Biological Factors
It’s super daunting to distil the gigantic field of biological psychology into a post. But here goes. There are two schools of thought on this: 1) there are anatomical differences in the “teen brain” that drives behavior. 2) The “teen brain” is a myth. Experiences create changes in the teen’s brain. Both camps do agree that there are anatomical differences in the brain that are occurring from childhood to adolescence and on to adulthood. What is the hotly debated issue is if these anatomical changes in the brain result in more risk-taking behavior.*

Anatomical Changes in the Teen Brain
Remember the process of executive functioning? Recent studies indicate that the prefrontal cortex—which is responsible for executive functioning–may be one of the most important distinctions between the teenage and adult brain. Recent fMRI studies show that from childhood (ages 8-13) through adolescence (14-17) and adulthood (18-30), the prefrontal cortex is used more during complex tasks. Additional regions of the brain (usually higher-order thinking skills) are also used more as the child ages.

Anatomically, the brain is undergoing synaptic pruning (eliminating unnecessary connections between the neurons) and increasing myelin (essentially insulation) around the axons that send signals from neuron to neuron. As a result, how the prefrontal cortex “communicates” with other areas of the brain is more efficient.

The general idea is that as you get older, your brain can distribute the workload of the decision making to many different areas of the brain. This is especially useful under stressful conditions, because one can recruit more areas than just the prefrontal cortex to take over.

So it’s conceivable that my tough guy student impulsively got in a fight because under stress, could not efficiently use his prefrontal cortex and other regions that help to inhibit behavior or evaluate long-term consequences.

Does the difference in the teen’s brain really cause his/her behavior?

Herein lies the controversy. There is a group of researchers who believe that the risk taking, novelty seeking, and impulsivity that are characteristic of adolescents may be hardwired in the brain. Remember that the pruning of grey matter in the brain does not reach the forebrain until adulthood, and the forebrain is where the planning, reasoning, and impulse control occur (remember, pruning is good, it increases efficiency). The brain-behavior connection is drawn based on subsequent studies of adolescents’ risk assessments, which are thought to require these areas of the brain.

A recent study showed that for adolescents, the perceived benefits of an action tend to outweigh and offset the risk. So basically the payoff of having your friends think you are the best coke drinker in the school outweighed the cost of puking. Likewise, the benefits of fighting a peer at lunch and keeping your “tough guy” image outweighs the cost of having to see the school psychologist and potential suspension.

And, because nothing is every that simple when dealing with adolescents, another group of researchers believes that the “Teen Brain” is a myth. The argument goes something like this: Snapshots of brain activity and their associated behaviors do not necessarily mean that the brain causes the problems encountered by teens. Considerable research shows that a person’s emotions and behaviors continuously change brain anatomy and physiology (e.g. stress, enriched environments, nutrition, exercise, and even meditation). So did the brain cause the behavior, or did the behavior alter the brain?

Further, anthropological research reveals that teens in many cultures do not experience these “teen problems” (at least not until Western schooling, movies, and television were introduced), making the “hardwiring” of the teen brain not universal. So in the case of my tough guy, the stress about his fight perhaps created hypersensitivity in dopamine-producing neurons, which altered his brain chemistry. And my happily chanting girls somehow escaped the teen problems because of their nurturing, healthy, and stress-free experiences.

I don’t know about you all, but it seems to me that this biological psychology lesson is a bit mind boggling.** Now pretend you’re 13 years old trying to figure it all out! Middle school kids are amazing.

*For more detail on the debate, refer to Scientific American Reports: Special Edition on Child Development © 2007. They lay it out quite well and include more detailed information on all the studies.

**Pun intended.

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