Research Reveals Five Distinct Stages of Brain Development
Shakespeare’s concept of the Seven Ages of Man might need some updating, according to recent findings from neuroscientists at the University of Cambridge. They propose that, rather than seven stages, there are actually five distinct phases of brain development throughout a human life.
In fact, research indicates that there’s an extended adolescent phase that can last into a person’s thirties. Also, there’s a period of stable high performance that can continue right until the mid-sixties.
Alexa Mousley, a researcher and Gates Cambridge Scholar, pointed out that while it’s known that the brain’s wiring is vital for our development, a comprehensive understanding of how these changes occur over a lifetime has been lacking. This study aims to fill that gap by identifying key phases of brain wiring throughout life.
The research involved analyzing MRI scans from over 3,800 individuals, from infants all the way to people in their nineties. The results, which were published in Nature Communications, highlighted four critical turning points in brain development, occurring around the ages of 9, 32, 66, and 83. These points effectively divide life into five distinct “epochs” inspired by brain structure.
The first phase, extending from birth to about age nine, shows that connections between different brain areas become less efficient. It’s more challenging for the brain to relay information across these areas—like a city with winding roads that make travel slower.
Despite this, the brain becomes better at handling specialized tasks during this time. Neurons begin to form stronger connections within specific areas, a process referred to as local segregation. The significant shift at age nine coincides with both improved cognitive abilities and an increased susceptibility to mental health issues.
As individuals transition from 9 to 32, connections across different brain regions improve, making communication much more efficient. Researchers note this time as an unexpectedly lengthy period of adolescence, leading up to a peak in performance typically reached in the early thirties.
Following this is a plateau from about ages 32 to 66, during which intelligence and personality traits tend to stay relatively stable.
Around age 66, another shift begins, marked by a gradual decline in the brain’s white matter, which facilitates communication between regions.
Finally, at age 83, the brain enters a stage where various areas become more isolated, and direct connections start to weaken. This could be seen as a neurologic echo of Shakespeare’s “second childishness,” with a growing reliance on local networks.
Duncan Astle, a neuroinformatics professor at Cambridge and a senior author of the study, noted that many people feel their lives are made up of different phases, and it appears our brains undergo similar transformations as well. He emphasized that numerous developmental, mental health, and neurological disorders are linked to brain wiring, suggesting that variations in this wiring can lead to challenges with attention, language, memory, and other behaviors.
Astle concluded by stating that grasping the brain’s structural journey as a series of significant turning points—rather than a consistent progression—could enhance our understanding of when and how its wiring may become vulnerable.
