Report on Progress: What Were You Thinking?!

“What Were You Thinking?!” is the title of the latest Report on Progress, where Marisa Silveri, Ph.D., gives insight into the teenage brain.

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The Neurological Excuse for Your Teen’s Idiotic Decisions

The word teenager is nearly synonymous with the words unstable, reckless and headache. Whether a parent’s teenage son is being dropped off by a squad car at 4 a.m. or a teacher’s student enters the classroom wearing a freshly dyed green mohawk and a nose ring, adults dealing with teenagers are continually baffled and often infuriated by the recklessness and stupidity of teen behavior. However, as David Dobbs points out in his article “Beautiful Teenage Brains” in the Oct. 2011 National Geographic, behavior that parents find most vexing in their teens are often those that are most important to their success later on as adults.

Scientists once believed the brain stopped developing at a young age, but with the development of brain scans, we now know that it continues to develop throughout adolescence and beyond. The National Institutes of Health (NIH) completed a study of the adolescent brain in the 1990s showing that between the ages of 12 and 25 human brains go through what Dobbs calls “extensive remodeling, resembling a network wiring upgrade.” During the teen years, myelin (the white, fatty matter that insulates axons) thickens, dendrites expand, and busy synapses grow richer and stronger while idle ones wane away. These changes combined with the thinning of the brain’s cortex—where most conscious thought is done—lead to a far more efficient brain.

Dobbs also describes how the strengthening links between the hippocampus (needed for memory) and, frontal areas (needed for forming goals and plans) begin to improve adolescents’ ability to integrate their experiences with their decision-making. With all these neurological improvements, one wonders why teenagers often make bad decisions. Dobbs notes that just as the changing body of a teenager produces a stumbling physical awkwardness, their changing brain creates a neural awkwardness and, initially, as he puts it, “it’s hard to get all those new cogs to mesh.”       

Neural awkwardness alone cannot explain why your rebellious 14-year-old has started hanging out with the wrong crowd. Teenagers are notoriously hormonal, and according to Dobbs, changes in the brain’s hormone receptors also influence the reckless behavior of adolescence by strongly enforcing social rewards. During the teen years, the brain becomes extremely sensitive to dopamine and oxytocin, producing a brain that is highly influenced by social interactions. Dobbs notes that scans of the teen brain indicate that it reacts to social inclusion and exclusion the same way it does with threats to physical well-being and food supply.   

Dobbs points to a study by developmental psychologist Laurence Steinberg illustrating adolescent susceptibility to social rewards and its effect on their behavior. Steinberg created a video game where participants had to drive across town as fast as possible. Game players often encountered yellow lights and had to judge whether to go through them or wait; they lost points if the light turned red as they were going through the intersection. When by themselves, teenagers had nearly identical results as adult players; however, when taking the test accompanied by other teenagers, teens went through twice as many red lights. Steinberg argues that teens have the ability to accurately judge risks, but “they gave more weight to the [social] payoff” of impressing their friends.

But what is the human payoff in running a red light with your friends in the back seat? Why haven’t we evolved to eliminate the impulsive and often destructive nature of this stage of development? In fact, Dobbs argues, evolution has enforced these traits in teenagers. He argues that a teen’s willingness to take risks increases the probability of more and better social connections, which has been shown to increase happiness and success in the long run. Humans are social creatures and teenagers are especially social humans. While risk-taking may lead teens down roads that parents would rather they avoid, it will also encourage them go out and explore the world beyond the comfort and security of their home. Exploration and risk-taking are essential to the development of a successful adult.

Dobbs suggests that parents continue to guide their teens but do so while giving them the independence they need to develop. As for me, I suggest parents read and learn from this article, but keep it hidden from their kids. Providing your kid with a legitimate scientific explanation for their misbehavior would give them a stronger defense in your next battle, and strengthen the infamous “but everyone else was doing it” explanation. I know if I had this argument when I was sixteen, it would’ve been among my arsenal of excuses for my own idiotic behavior:

“Mom, I’m sorry! But it’s not my fault I hung out with my friends instead of studying for my chemistry test; I am neurologically programmed to make decisions based on social rewards rather than consequences!”

–Simon Fischweicher

Source: Dobbs, David, (2011). Beautiful Teenage Brains. National Geographic, 220(4), 36-59.  


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