Decision Making and Reward in Frontal Cortex

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3129331/

Your frontal lobe contains brain areas that manage who you are — especially your personality — and how you behave. Your ability to think, solve problems and build social relationships, sense of ethics and right vs. wrong all rely on parts of your frontal lobe.

Experts know this because of a railroad foreman named Phineas Gage. In 1848, an accidental explosion at a railroad construction site propelled an iron rod through Gage’s head, destroying the left side of his frontal lobe. Before the accident, Gage was a calm, respected leader among his coworkers. Gage survived, but after the accident, his personality changed. He would lose his temper, act disrespectfully and constantly use profanity.

However, Gage’s personality changes weren’t permanent. Four years after his accident, Gage moved to Chile in South America and became a stagecoach driver. Somewhere in late 1858 or early 1859, a doctor who examined Gage said he was physically healthy and showed “no impairment whatever of his mental faculties.”

While Gage mostly recovered from the accident, he died from seizures in San Francisco in 1860. The seizures were very likely the result of damage from the accident. However, his case remains one of the most useful in modern medicine’s understanding of what the frontal lobe does, especially when it comes to your personality.

The Pre-Frontal Cortex

One of the biggest differences researchers have found between adults and adolescents is the pre-frontal cortex. This part of the brain is still developing in teens and doesn't complete its growth until approximately early to mid 20's. The prefrontal cortex performs reasoning, planning, judgment, and impulse control, necessities for being an adult. Without the fully development prefrontal cortex, a teen might make poor decisions and lack the inability to discern whether a situation is safe. Teens tend to experiment with risky behavior and don’t fully recognize the consequences of their choices.