According to the most recent research and cognitive studies, psychologists and neuroscientists believe human brains continue developing through the 20s, 30s and even into the early 40s. Previously, medical professionals believed human brains reached a development cutoff point sometime in the late adolescent years through the early 20s. However, brain scans, cognitive tests and other medical advancements have let researchers explore brain activity in greater depth and realize that some, if not most, regions of human brains continue growing well into adulthood.
Some debate remains over exactly when the brain reaches maturity, but most experts agree that brains change shape and size through early adulthood. According to neuroscientists at the Institute of Cognitive Neuroscience at University College London, adult brains continue learning and developing long past adolescence. The prefrontal cortex, according to researchers, shows the greatest amount of continual growth. This region develops slowly and reaches full maturity after other areas of the brain.
The prefrontal cortex plays a key role in cognitive tasks and controlling behavior. It enables high-level thinking, sound judgment, risk assessment and planning. The prefrontal cortex also produces some personality traits and determines how people feel and act in social situations.
In addition to brain growth, hormones continue developing and changing through the 20s, much later than previously thought, as reported by the BBC. These continual cognitive and physical developments make some psychologists advocate for the redefining of adolescence and even age of adulthood.