Scientists recently uncovered that human brain development unfolds in five distinct stages. This study, which analyzed brain scans from nearly 4,000 individuals ranging from infants to 90-year-olds, highlights how our neural connections evolve throughout life.
These five key phases are marked by four major “turning points” around ages 9, 32, 66, and 83. Professor Duncan Astle from Cambridge University explained, “Many of us see our lives as a series of phases, and it appears that our brains experience similar changes.” Understanding these shifts helps us grasp when the brain might be more vulnerable to disruptions.
The first stage is from birth to age 9. During this time, babies’ brains undergo rapid development. This phase is characterized by “network consolidation,” where excess synapses—the connections between neurons—are trimmed, leading to a more efficient brain structure. Interestingly, as synapses decrease, the efficiency of brain wiring appears to dip.
The second stage lasts until around 32. In adolescence, the brain’s white matter—the part responsible for communication between different areas—grows and becomes more organized. This organization is linked to improved cognitive abilities. Researcher Alexa Mousley noted, “While individuals in their late 20s aren’t thinking like teenagers, there’s a consistent pattern of change.”
Starting from 32, the brain’s structure stabilizes, corresponding with noted plateaus in intelligence and personality. This may relate to significant life events, such as starting a family. Mousley highlights that brain changes after childbirth indicate milestones might influence brain development.
As we reach age 66, we enter an “early aging” phase. The final stage, around 83, marks a “late aging” phase when brain connectivity begins to decline. Research suggests that this degeneration of white matter is linked to common age-related effects.
Understanding these phases can shed light on mental health challenges, especially those emerging during adolescence. The changes in our brain mirror the stages of life, and awareness of this progression can help us navigate its complexities.
For further reading on brain development and its effects on mental health, check out this Nature article.
