The Washington Post
Young Adulthood: 20 to 39
The mid-to-late 20s are often thought of as a kind of “peak” of brain development or an example of when the brain has “matured.” This myth stems in part due to the observation that white matter volume, a proxy for the “speed” of information processing, reaches a high level at these ages.
Neuronal networks are continually honed and adjusted into young adulthood, especially those involved in rational thought and considering future consequences. Yet, the brain is by no means “done” with its development.
As the brain progresses into the 30s and 40s, adult synaptic plasticity, or the ability for connections to strengthen or weaken in response to activity changes, is thought to reprioritize rather than diminish.
“The system is just working differently. It’s moved into something that’s maybe a little more strategic and longer term, and not into ‘I need to remember exactly what this is and be really quick and sharp like I was in my 20s,’ ” said Mark Harnett, associate professor of brain and cognitive sciences at MIT who studies how neurons communicate in circuits and networks underlying complex behaviors. But those two things “are actually challenging to implement simultaneously.”