The development of the brain goes through five stages: "True adulthood" begins at 32? The latest neuroscience outlines the "five life stages."

"The Brain Undergoes a Complete Renewal Five Times in Life"—The Study That Stirred the World

"The human brain undergoes a massive 'rewiring' five times in a lifetime"—such headlines have been buzzing across European media and science news sites since the end of November.op-online.de

The research was conducted by a neuroscience team at the University of Cambridge. They scanned the brains of about 3,800 individuals aged 0 to 90 without neurological disorders using a type of MRI (diffusion MRI) and compared the connectivity of brain networks by age. They found an average of four major turning points where wiring patterns were significantly reorganized. These ages were approximately 9, 32, 66, and 83. These four curves divide the brain's lifespan into five "eras."University of Cambridge

German news sites and media from various countries introduced this study as "The brain structure goes through five phases from childhood to old age." Particularly, the notion that "adolescence lasts until 32" and "adulthood mode starts at 32" made a strong impact on social media.op-online.de

Interpreting the Five Phases in Everyday Terms

First, let's organize the five eras of the brain discovered by the research team into words with a sense of everyday life.University of Cambridge

1. Phase 1: Ages 0–9 "Full Throttle Construction Period"

2. Phase 2: Ages 9–32 "Extended Adolescence & Growth Period"

3. Phase 3: Ages 32–66 "Stable Adult Mode"

4. Phase 4: Ages 66–83 "Quietly Reorganizing 'Early Aging' Period"

5. Phase 5: Age 83 and Beyond "Reduced Connections 'Selective Member System' Period"

What exactly is happening in the brain during each phase?

Phase 1: Ages 0–9 "Connect Everything for Now" Construction Mode

The brain at birth wires a large number of circuits, even those whose necessity is unknown. This is a period when an excess of synapses, the connection points of nerves, is created, followed by the process of "pruning," where only frequently used circuits are retained, and the rest are eliminated.University of Cambridge

• Used Circuits = Surviving Lines

• Unused Circuits = Gradually Removed

As a result, circuits for "frequently heard words," "often seen people," and "frequently used movements" become like thick highways.

The study showed that this network organization reaches a milestone around the age of 9. This timing coincides with a period when academic and cognitive abilities begin to grow significantly, while developmental characteristics and mental issues such as anxiety and depression are also likely to emerge.op-online.de

From the Perspective of Parents and Teachers,

• "What experiences to frequently provide" determines brain wiring more than "how to teach."

• Around age 9 is both a "growth period" and a "stumbling period."

Being aware of this might change how you perceive children's behavior.

Phase 2: Ages 9–32 A World Rapidly Expands, Extended Adolescence

After age 9, the brain shifts from "content organization" to "communication efficiency."
Analysis of diffusion MRI shows that during this period, brain networks become

• capable of quickly exchanging information between distant regions

• Overall, "shortcuts" increase, shortening the journey

indicating an efficient structure.University of Cambridge

According to the research team, "efficiency improvement continues only in this adolescent phase." It is a golden period where many abilities, such as quick information processing, flexible thinking, and multitasking absorption, are likely to grow.University of Cambridge

However, on the other hand,

• emotional waves tend to become larger

• impulsivity and high-risk behaviors are more likely to occur

• the onset of mental disorders such as anxiety and depression is also common

indicating a "fragility." It is a period when the brain is dynamically reorganizing, making it highly susceptible to environmental factors.

What is surprising is that this phase is said to continue until around age 32.
Despite the fact that many countries have milestones like "adulthood at 18" or "legal drinking age at 20," in terms of brain wiring, the "adolescent mode" continues until the early 30s.University of Cambridge

Phase 3: Ages 32–66 Entering Adult Mode and a Long Stable Period

Around age 32, the brain's network undergoes a major directional shift. Researchers describe this as "the most significant turning point in life structurally."University of Cambridge

The adulthood that begins here is characterized by

• relatively stable brain wiring with fewer dramatic changes

• indicators such as intelligence and personality tend to show a "plateau"

• networks gradually becoming "specialized and compartmentalized"

These are the characteristics.

This "stability" also means that "habits become fixed." Thought patterns, work methods, and relationship styles... For better or worse, this is a period when one's individuality solidifies.

However, stability does not mean "unable to change." It is known that brain plasticity (the ability to change) continues throughout life, and many people acquire new languages or skills after their 30s.

What is important in this phase is

• whether you consciously seek "new stimuli"

• or

• confine yourself to familiar patterns

This choice will likely affect how you perceive the aging phase later on.

Phase 4: Ages 66–83 Quietly Progressing "Network Reorganization"

Around age 66, a turning point comes that the research team calls "not flashy but significant change."University of Cambridge

During this period,

• the white matter (wiring part) begins to deteriorate gradually

• the overall structure of the network is quietly reorganized

• the risk of physical diseases affecting the brain, such as hypertension, increases

These early signs of aging begin to appear.op-online.de

That said, it is not about "immediately developing dementia." Rather, this phase is said to be
a zone where the speed of aging can vary greatly depending on lifestyle and social connections.

• Moderate exercise

• Managing salt intake and blood pressure

• Social interactions through hobbies or work

• Opportunities to challenge new things

These elements are thought to support the "reserve capacity" of brain networks.

Phase 5: Age 83 and Beyond A Time of Reduced Connections, Relying on "Selected Circuits"

Around age 83, the brain enters the final phase, the late aging period. The research data only goes up to age 90, but in this zone,

• overall connections further decrease

• there is a stronger tendency to rely on a few important networks

These characteristics were observed.University of Cambridge

In other words,

• while the brain used "broad and shallow" circuits when young,

• it operates by relying on "narrow and deep" circuits as one ages,

which might be an easy way to understand it.

In this phase,

• long-standing habits

• cherished relationships

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