Exploring how the brain develops during adolescence and its impact on decision-making processes and risk-taking behavior.
Dispelling the myth that an adult brain is significantly larger than an adolescent’s brain is important. The sizes are quite similar; it’s the dynamic changes in the adolescent brain that are notable. Interestingly, the brain keeps on developing until the late 20s. Neuroscience tells us that we should never judge an adolescent for occasional rude behavior, as you may not understand the complexities of their brain development. Adolescence marks a peak period of brain changes. Until puberty, the number of brain cells increases rapidly in the brain’s frontal region. Most of the changes occur in the prefrontal cortex, which is crucial for decision-making.
Additionally, there is an increase in *myelination and **synaptic pruning in the prefrontal cortex during adolescence, which increases the efficiency of information processing and strengthens neural connections between several brain regions. However, this growth is both time-consuming and uneven.
The limbic system, responsible for determining rewards and punishments, understanding emotional experiences, and processing social information, develops much later than the prefrontal cortex. This delayed development increases the likelihood of adolescents engaging in risky behavior.
Pubertal hormones directly target the amygdala, leading to powerful sensations (Romeo, 2013). [1] Brain scans confirm that cognitive control, as revealed by fMRI studies, is not fully developed until adulthood due to limited connections and engagement in the prefrontal cortex (Hartley & Somerville, 2015). [2] Remember, this area is responsible for judgment, impulse control, and planning, and it continues to mature into early adulthood (Casey, Tottenham, Liston, & Durston, 2005).
Moreover, transitions in the levels of certain neurotransmitters like dopamine and serotonin in the limbic system make adolescents more emotional and responsive to rewards and stress. Dopamine, a neurotransmitter associated with pleasure and environmental attunement during decision-making, increases in the limbic system during adolescence, with a corresponding rise in dopamine input to the prefrontal cortex. This heightened dopamine activity can lead to increased risk-taking and vulnerability to boredom. Serotonin, involved in mood and behavior regulation, is known as the “calming chemical,” as it alleviates tension and stress. It also neutralizes the energy and potential neglectfulness initiated by dopamine. Defects in serotonin processing can result in impulsive or violent behavior.
When the brain’s chemical system functions well, these chemicals interact to balance out extreme behaviors. However, when stress, arousal, or sensations become overwhelming, the adolescent brain is inundated with impulses that overpower the prefrontal cortex, leading to increased risk-taking behaviors and emotional outbursts. This is likely due to the ongoing development of the frontal lobes. Later in adolescence, the brain’s cognitive control centers in the prefrontal cortex develop, enhancing self-regulation and future orientation. The differing timelines of brain region development contribute to greater risk-taking during middle adolescence, as adolescents seek thrills from risky behaviors such as reckless driving, smoking, or drinking, while not yet having fully developed cognitive control to resist impulses or equally consider potential risks (Steinberg, 2008). [3] Laurence Steinberg, a leading expert on adolescent development, compares this to engaging a powerful engine before the braking system is in place, making adolescents more prone to risky behaviors than children or adults.
*myelination- separator of neurons’ axons with a greasy substance (myelin sheath) that speeds up the processing of information; myelination starts to increase in the prefrontal cortex during adolescence
**synaptic pruning- connections in the brain that are not used much are lost so that other connections can be strengthened; this pruning happens with prefrontal cortex connections in puberty
Author – Sukhmeet Kaur
Welham Girls School
