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 5, 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 because 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.
This includes the formation of new neural connections (blooming) and the subsequent reduction of these connections (pruning) 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.
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), where children gain a firm grasp on numbers and mathematical operations and master concepts like conservation, indicating 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 achievement of full maturity in the prefrontal cortex, leading to stabilization of functions such as emotional control, which is linked to the prefrontal cortex’s role in regulating emotions and guiding goal-directed behavior.
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, and emerging research suggests that the ventromedial and dorsomedial prefrontal cortices may play distinct roles in memory and decision-making processes.
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.
Hormones, such as perinatal androgens like testosterone, have “organizing effects” on brain structures, contributing to areas that are sexually dimorphic, meaning they differ between sexes (for example, the sexually dimorphic nucleus is larger in males).
However, it’s important to note that while these biological differences are observed, it’s still debated whether they are direct causes of behavioral differences or if they are also shaped by social and environmental influences.
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.
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.
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 can significantly reduce the likelihood of a child with certain developmental challenges (like Fetal Alcohol Syndrome) ending up in prison if raised in a stable, nurturing environment and diagnosed early.
Different regions within the prefrontal cortex mature at varying rates, and in conditions like ADHD, some areas may develop more slowly or function less efficiently. This can affect attention, impulse control, and working memory. For example, the dorsolateral prefrontal cortex—key for focus and planning—is often less active or delayed in individuals with ADHD, contributing to common symptoms.
Can lifestyle affect brain development?
Yes, your lifestyle significantly affects your brain’s development.
Sleep is vital, as 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.
