The prefrontal cortex — the part of the brain responsible for planning, impulse control, and decision-making – doesn’t fully mature until around age 25. This makes it the last part of the brain to fully develop.
While a child’s brain grows rapidly in size during early childhood, the prefrontal cortex continues developing in complexity and function well into early adulthood.
This extended timeline helps explain why teenagers often struggle with emotional regulation, risk assessment, and long-term thinking.
Understanding when and how this part of the brain develops can shed light on everything from adolescent behavior to adult responsibilities.
Key Takeaways
- The prefrontal cortex usually finishes developing around age 25.
- It controls higher-level functions like planning, self-control, and judgment.
- Brain size is mostly complete by age 6, but maturity takes much longer.
- Adolescents often act impulsively because their prefrontal cortex is still developing.
- Healthy development is shaped by sleep, stress, relationships, and life experiences.
What is the prefrontal cortex?
The prefrontal cortex (PFC), located in the frontal lobe, is vital for higher-level cognitive functioning.
It is responsible for executive functions, including planning, judgment, and impulse control.
This area also supports self-regulation, enabling individuals to adjust their actions to achieve goals, like remembering to go to the store instead of taking a default route home.
The prefrontal cortex is the last to develop. It handles complex functions like reasoning, planning, and self-control, which require extensive neural wiring.
These advanced abilities build on earlier brain systems, so this region matures slowly, continuing into the mid-20s to allow time for fine-tuning through life experience and learning.
Brain growth vs. brain maturity
Brain growth refers to the physical increase in the brain’s size. A child’s brain reaches approximately 90% of its adult size by age 6, with rapid development in the frontal lobes during early childhood.
Brain maturity, however, is a more complex process involving the “wiring” and organization of the brain, rather than just its volume.
Blooming comes first: the brain forms new neural connections. Pruning follows, reducing unneeded connections to enhance efficiency, a process that continues through childhood and into adolescence.
The prefrontal cortex continues to mature into early adulthood. Thus, maturity signifies functional development and intricate organization, beyond mere physical size.
The Gogtay et al. (2004) Brain-Scan Study
The clearest evidence for this back-to-front pattern comes from a study that scanned children’s brains repeatedly as they grew up.
- Aim: To map, in living children, the order in which different brain regions mature from childhood into early adulthood.
- Method: Thirteen healthy children had repeat MRI scans every two years for 8–10 years, from about age 4 to 21. This built a time-lapse map of grey-matter change across the whole cortex.
- Results: Brain regions matured in a clear order. Areas handling basic senses and movement matured first, and the prefrontal cortex, which handles higher-level thinking, matured last, still developing into late adolescence and beyond.
- Conclusion: The prefrontal cortex is the last part of the cortex to fully mature. This is the direct brain-scan evidence behind the idea that it isn’t finished until the mid-20s.
Prefrontal Cortex Development by Age
Early Childhood (0–5)
During early childhood, specifically from ages 3–6, the frontal lobes of the brain experience rapid growth. By the age of 6, the brain is approximately 90% of its adult size.
While there is rapid brain growth, the prefrontal cortex’s functions are still limited.
Children at this stage are still developing basic cognitive skills, as seen in Piaget’s preoperational stage (2–7 years).
This stage is characterized by developing symbolic thought and language, but still largely egocentric thinking, and lacking advanced logical reasoning.
Emotional regulation remains immature, with toddlers cycling through emotions quickly.
Middle Childhood (6–12)
Through the elementary school years (ages 6–11), all lobes of the brain, including the frontal, temporal, occipital, and parietal lobes, continue to grow in size.
Cognitive skills expand, and thought processes become more logical and organized, particularly when dealing with concrete information.
Children at this age develop the ability to plan and work toward goals, though their attention spans tend to be limited until around age 11.
This aligns with Piaget’s concrete operational stage (7–11/12 years). Children in this stage gain a firm grasp on numbers and mathematical operations, and they master concepts like conservation, showing growing attention and planning skills.
Adolescence (13–19)
The adolescent brain remains under development, with brain growth continuing into the early 20s.
This period involves a continuation of synaptic pruning, where neural connections are reduced to enhance efficiency.
Adolescents may exhibit increased risk-taking behaviors and emotional outbursts, possibly because the frontal lobes, which are responsible for judgment, impulse control, and planning, are still maturing.
The balance between the immature prefrontal cortex and the limbic system can contribute to high impulsivity.
More complex thinking abilities emerge, including abstract thought, and the ability to consider multiple points of view and debate ideas.
Early Adulthood (20–25)
The frontal lobes, including the prefrontal cortex, continue their maturation into early adulthood.
The prefrontal cortex, responsible for higher-level cognitive functioning, judgment, and decision-making, reaches its full development around 25 years old.
This stage is associated with stronger long-term planning, reasoning, and the final stages of executive function development.
Cognitive abilities, such as crystallized intelligence, remain steady and may even improve.
Around Age 25 and Beyond
By approximately age 25, the frontal lobes are considered fully developed.
This marks the typical age at which the prefrontal cortex reaches full maturity. Functions such as emotional control stabilize as a result, reflecting the region’s role in regulating emotions and guiding goal-directed behavior. Maturation is gradual. It varies between individuals too, rather than switching on at a fixed birthday.
While physical decline may begin in middle adulthood, cognitive decline, particularly in fluid intelligence, does not generally begin until later, and crystallized intelligence can remain steady or improve.
Different regions within the prefrontal cortex mature at varying rates. Emerging research suggests that the ventromedial and dorsomedial prefrontal cortices play distinct roles in memory and decision-making.
Does the Prefrontal Cortex Develop Differently in Males and Females?
There are slight differences in the timing of prefrontal cortex development between males and females.
For example, young girls tend to show earlier development in their frontal lobes, which are linked to language skills and regulating aggression.
In contrast, boys’ brains may develop faster in visual regions, which helps with visual and spatial tasks like geometry.
This development is influenced by a combination of hormones and genetics.
Perinatal androgens like testosterone have “organizing effects” on the brain. These hormones shape brain areas that are sexually dimorphic, meaning they differ between sexes (for example, the sexually dimorphic nucleus is larger in males).
These biological differences are real, but their behavioral impact is debated. Sex differences in brain development are group averages. Individual overlap is large, and environment and social context also shape outcomes.
Why Prefrontal Cortex Development Matters
This extended development has several important implications:
Risk-taking and Emotional Regulation in Teens
As the frontal lobes are still maturing, adolescents may engage in increased risk-taking behaviours and emotional outbursts.
Their brain systems that regulate impulse control are not yet fully developed.
This is why it can be unfair to expect teens to have adult levels of organizational skills or decision-making before their brains are finished developing.
This pattern has a name: the dual-systems model. It describes a mismatch between two brain systems that mature on different timelines.
The brain’s reward and emotion systems, including the ventral striatum and amygdala, mature early, around puberty. The prefrontal cortex, which should regulate them, matures much later.
The result is a powerful reward-and-emotion engine paired with an under-developed brake. This combination helps explain teenagers’ heightened sensation-seeking, susceptibility to peer influence, and emotional volatility, on top of the risk-taking already described above.
Implications for Parenting and Education
Understanding the ongoing maturation of the prefrontal cortex helps parents and educators set realistic expectations for adolescents’ cognitive abilities.
It informs teaching methods that are appropriate for a student’s developmental stage.
Research supports specific strategies. A review of intervention studies found that programmes combining physical activity, mindfulness-style practice, and repeated practice of executive skills work best (Diamond & Lee, 2011). Computer-based “brain-training” drills alone were less effective.
Programmes that also address children’s emotional and social needs work even better than those that target thinking skills alone.
Legal and Societal Considerations (e.g., Juvenile Justice)
The immaturity of brain systems regulating impulse control contributes to why adolescents might engage in risky or unlawful behaviours.
This neurological understanding is a factor in legal systems, particularly juvenile justice, when considering a person’s functional impairment and legal responsibility.
Early recognition and support help. A child with developmental challenges, such as Fetal Alcohol Syndrome, is significantly less likely to end up in prison if diagnosed early and raised in a stable, nurturing environment.
Different regions within the prefrontal cortex mature at varying rates. In conditions like ADHD, some areas develop more slowly or function less efficiently, affecting attention, impulse control, and working memory.
A large brain-imaging study compared cortical maturation in more than 800 children with and without ADHD (Shaw et al., 2007). The order was the same. The timing was not.
Children with ADHD reached peak cortical thickness at a median age of 10.5, compared with 7.5 in typically developing children. The delay was greatest in the dorsolateral prefrontal cortex, the region key for focus and planning, often less active in people with ADHD and linked to common symptoms.
Can lifestyle affect brain development?
Yes, your lifestyle significantly affects your brain’s development.
Sleep is vital. Good quality sleep helps your brain organize and consolidate memories, while a lack of it can make emotional areas like the amygdala overreact and impair learning capacity.
Chronic stress, especially in early life, can damage brain circuits, lower stress thresholds, and contribute to mental health issues like depression. This can even reduce prefrontal brain functioning.
Nutrition is crucial for neurocognitive development from pregnancy onwards.
Relationships and social support are protective factors, with nurturing environments buffering stress and contributing to positive personality development.
Conversely, trauma or adversity in childhood can lead to changes in brain structure, impacting emotion regulation and increasing vulnerability to mental disorders.
References
Diamond, A., & Lee, K. (2011). Interventions shown to aid executive function development in children 4 to 12 years old. Science, 333(6045), 959–964. https://doi.org/10.1126/science.1204529
Gogtay, N., Giedd, J. N., Lusk, L., Hayashi, K. M., Greenstein, D., Vaituzis, A. C., Nugent, T. F., Herman, D. H., Clasen, L. S., Toga, A. W., Rapoport, J. L., & Thompson, P. M. (2004). Dynamic mapping of human cortical development during childhood through early adulthood. Proceedings of the National Academy of Sciences, 101(21), 8174–8179. https://doi.org/10.1073/pnas.0402680101
Shaw, P., Eckstrand, K., Sharp, W., Blumenthal, J., Lerch, J. P., Greenstein, D., Clasen, L., Evans, A., Giedd, J., & Rapoport, J. L. (2007). Attention-deficit/hyperactivity disorder is characterized by a delay in cortical maturation. Proceedings of the National Academy of Sciences, 104(49), 19649–19654. https://doi.org/10.1073/pnas.0707741104
