Your brain has 5 'eras': What does it mean?
25 Nov 2025

A new study has identified five major "eras" in human brain development, marking significant changes in neural wiring from infancy to old age.

The research, which analyzed brain scans of nearly 4,000 people aged between less than one and 90 years, identified four key "turning points" around the ages of nine, 32, 66, and 83.

These turning points indicate shifts in brain organization onto different trajectories.

Understanding brain development through 'eras'
Brain phases

Professor Duncan Astle from Cambridge University, a senior author of the study, said that just like our lives are divided into different phases, our brains also go through these "eras."

He emphasized that this understanding can help us identify when and how the wiring of our brain is vulnerable to disruption.

The study mapped neural connections and their evolution throughout life, revealing these five broad phases.

The 5 epochs of brain development
Developmental stages

The study identified five major "epochs" in human brain development: the childhood period (birth to nine years), the adolescent phase (up to 32 years), adult mode (early 30s onward), early aging phase (around 66 years), and late aging phase (around 83 years).

Each of these phases is characterized by distinct changes in neural connections, cortical thickness, and folding patterns.

Changes in brain architecture and connectivity
Structural shifts

The study found that from infancy to childhood, the brain undergoes "network consolidation," where synapses are pruned and the more active ones survive.

During this period, the efficiency of the brain's wiring decreases as gray and white matter grow rapidly in volume.

In adolescence, white matter continues to grow in volume while organization of communication networks is refined, leading to improved cognitive performance.

Brain architecture stabilizes in adulthood
Stability phase

Around age 32, the brain architecture stabilizes compared to previous phases, which corresponds with a "plateau in intelligence and personality."

This is when the brain's neural wiring shifts into adult mode, marking the longest era of development.

The study also noted that life events such as parenthood may influence some of these changes, although this wasn't explicitly tested in the research.

Later years mark early and late aging phases
Aging stages

The study also identified early and late aging phases of brain architecture, starting around age 66 and taking shape around age 83, respectively.

These later two turning points were characterized by decreases in brain connectivity, which are believed to be associated with aging and degeneration of white matter in the brain.