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At What Age Is The Brain Fully Developed?

It is widely debated as to which age the brain is considered “fully mature” or developed. In the past, many experts believed that the brain may have been done developing in the mid to late teens. Then along came some evidence to suggest that development may last until at least age 20. These days, a consensus of neuroscientists agree that brain development likely persists until at least the mid-20s – possibly until the 30s.

The fact that our brains aren’t developed until the mid 20s means that “legal adults” (those age 18+) are allowed to make adult decisions, without fully mature brains.  Someone who is 18 may make riskier decisions than someone in their mid-20s in part due to lack of experience, but primarily due to an underdeveloped brain.  All behaviors and experiences you endure until the age of 25 have potential to impact your developing brain.

At what age is the brain fully developed?

Although brain development is subject to significant individual variation, most experts suggest that the brain is fully developed by age 25. For some people, brain development may be complete prior to age 25, while for others it may end after age 25.  The mid-20s or “25” is just an average age given as checkpoint for when the brain has likely become mature.

It may seem logical that those aged 18 to 25 are completely mature, the brain still is maturing – specifically the area known as the “prefrontal cortex.” Changes occurring between ages 18 and 25 are essentially a continued process of brain development that started during puberty. When you’re 18, you’re roughly halfway through the entire stage of development. The prefrontal cortex doesn’t have nearly the functional capacity at age 18 as it does at 25.

This means that some people may have major struggles with impulsive decisions and planning behavior to reach a goal. The brain’s reward system tends to reach a high level of activation during puberty, then gradually drifts back to normal activation when a person reaches roughly the age of 25. Adults over the age of 25 tend to feel less sensitive to the influence of peer pressure and have a much easier time handling it.

How the brain changes during development

From early stages of adolescence into adulthood, the brain experiences major growth and pruning. Initial developments begin near the back of the cortex, and tend to finish in the frontal areas (e.g. prefrontal cortex). There are a couple key ways by which the brain changes during various stages of development including: myelination as well as synaptic pruning.

  1. Myelination: The nerve fibers in your brain are covered with a substance called “myelin.” This helps provide insulation so that neurons can effectively transmit signals. During developmental stages, the process of myelination promotes healthy brain functioning and allows for more complex functions.
  2. Synaptic pruning: This is a process by which brain synapses are selectively “pruned” or eliminated throughout brain development. The process of synaptic pruning tends to peak during teenage years, and wanes in later adolescence. It should be noted that the pruning occurs until the brain is fully developed (likely into the mid-20s). This allows for more efficient brain functioning.
  3. Increased connectivity: The connections between brain regions appear to be strengthened, thus making communication more efficient. The brain is able to transmit greater amounts of information between regions and becomes better at planning, dealing with emotions, and problem solving.
  4. Executive functions: A majority of the executive functions that we develop are via the prefrontal cortex. This allows us to help assess risk, think ahead, evaluate ourselves, set goals, and regulate our emotions. Although many of these functions are developed during teenage years, they are still under slight development and strengthened until our mid-20s.

What does the prefrontal cortex do?

There are a variety of functions for which the prefrontal cortex is responsible. Although significant development of the prefrontal region occurs during adolescence, experts argue that it continues until (at least) our mid 20s.

  • Attention: The ability to focus on one thing, while ignoring distractions is a function of our prefrontal cortex. Those with attentional deficits (e.g. ADHD) may have abnormalities within the prefrontal region. Similarly, those who abuse drugs and/or alcohol may end up with attention problems as the brain forms.
  • Complex planning: The prefrontal region is responsible for complex planning. Anytime you set a goal that requires some degree of planning, your prefrontal region is at work. Planning out tasks in your day, developing a business plan, etc. – this region is responsible. An underdeveloped prefrontal region means that your planning capabilities haven’t been solidified.
  • Decision making: We often struggle to make good decisions when we are teenagers, but as we enter our 20s, our decision making improves. This is due to the fact that our prefrontal cortex helps us think logically and make more calculated assessments of situations. Our brain weighs the risks and tells us whether a certain behavior or choice is a good idea vs. a bad one.
  • Impulse control: Struggling with impulsivity is often related to deficits in the prefrontal cortex. The ability to maintain self-discipline and avoid impulsive behaviors hasn’t reached its peak until the 20s. This means that if you struggle with impulsivity when you’re 18, it may get better as you continue to age.
  • Logical thinking: Justifying behaviors based off of emotions rather than logic is common among teens. When the prefrontal cortex fully develops, logical thinking simultaneously improves. This means you will be better at rationalizing and making smarter choices. It also means that your ability to write and solve math problems will improve.
  • Organized thinking: Organizing your thinking can be difficult when you’re a teen. A barrage of thoughts are typically influenced by hormones and you may have concentration difficulties. As you continue to age and your thoughts become more organized. The organization of your thoughts is a result of your prefrontal cortex.
  • Personality development: Your personality is directly expressed based off of your prefrontal cortex. Without proper stimulation, you may struggle with identity issues and developing a favorable personality. Since personality development continues throughout the 20s, you may want to consider how environmental inputs may affect who you are.
  • Risk management: The ability to assess risky situations and determine whether they will result in long-term benefit is a byproduct of your prefrontal cortex. Those who are poor at assessing risk may have underdeveloped prefrontal regions. The ability to turn down immediate gratification for long-term rewards is a result of this region.
  • Short-term memory: Your short-term memory function is influenced by the prefrontal cortex. When still in development, your short-term memory isn’t as good as it will be by the time you’re 25. As the brain continues to mature, your cognitive function and memorization capacity will improve.

Promoting Healthy Brain Development

If you are under the age of 25 and your brain is not yet fully developed, you may want to take advantage of this critical period. This means that you can effectively be a co-creator in how your brain decides to mold itself. Engaging in healthy behaviors and giving your brain optimal stimulation will help ensure healthy prefrontal cortex development.

  • Cognitive challenges: Giving your brain cognitively demanding or challenging tasks can help stimulate development. Examples of things that may boost brain function include: brain training games and applications (e.g. Lumosity), Dual N-back training, working memory training, writing, regurgitating and processing information, etc.  All activities that may help increase IQ may improve brain development.
  • Dietary intake: It is widely disputed as to what diet should be eaten during adolescence to ensure healthy brain development. It is recommended to eat plenty of vegetables, some fruits, proteins, fats, and the right carbohydrates. Avoiding artificial sweeteners and substances with high sugars may be beneficial as well.
  • Education: Proper education and/or learning can go a long way towards improving brain development. The more you learn before the age of 25, the more solidified that information will (likely) become. Getting a good education provides cognitive stimulation to the brain in a variety of ways.
  • Environmental enrichment: There are numerous studies showing the benefits of environmental enrichment on the brain. It appears as though living in an enriched environment such as: going to a great school, having positive social connections, access to healthy foods, trying new things, learning new skills, and having lots of resources can improve the brain’s development.
  • Exercise: Getting enough exercise has become highly underrated in a society focused on immediate gratification. The psychological benefits of exercise are very significant; blood flow improves, neurotransmitter levels get optimized, your emotions become more positive, and you can actually grow new brain cells.
  • Meditation: Not only is meditation a great activity for stress reduction, but there are studies demonstrating (that if you’re doing it properly) it can enhance development of your prefrontal cortex. This makes you more resilient to stress, improves your attention, and clarity of thinking. Consider taking up a meditation practice if you want to improve brain development.
  • Sleep optimization: Most people talk about pulling all-nighters like it’s an impressive feat. In reality, not getting enough sleep and/or poor sleep quality can detrimentally affect brain development. To ensure that your brain develops properly, give it enough time to recover and rejuvenate itself by getting adequate sleep.
  • Socialization: Positive social contacts and/or friends are what humans need in order to stimulate brain development. Staying involved in groups and social functions is a great way to stay connected and can reap benefits for the developmental outcome of your brain.
  • Stress reduction: A daily practice of stress reduction can go a long way towards reducing activity in anxious, stress-provoking brain centers and can enhance development of the prefrontal cortex. Brains that are under chronic stress may not develop as well as those that are allowed some down-time for relaxation.
  • Supplementation: Certain supplements may help strengthen development of the brain. These include things like fish oils (omega-3 fatty acids), antioxidants, etc. It is important to weigh the pros and cons of each supplement before taking it. Also realize that while supplementation can provide benefit, getting proper sleep and eating a healthy diet are more beneficial.

Detrimental influences upon brain development

Unfortunately many people are exposed to things that may have a detrimental impact on the development of their brain. These include negative social influences, substance abuse, and/or prolonged levels of high stress. Although some people will have more resilient brains than others as a result of genetics, it is recommended to minimize exposure to problematic stimuli and scenarios.

  • Alcohol abuse: Drinking excessive amounts of alcohol to the point of abuse may have an impact on the developing brain. It is critical to avoid abusing alcohol while the brain is still developing as excess drinking can disrupt formation of the prefrontal cortex. Some reports have gone as far as to suggest alcohol damages the brains of teens.
  • Chronic stress: If you are constantly under duress and/or have severe anxiety, it is best to take steps to minimize it. Excessive amounts of stress have been documented as disrupting the architecture of the developing brain. Furthermore, high stress may inhibit our brain’s ability to mitigate stress in the future.
  • Drug abuse: It is recommended to avoid exposure to illicit drugs regardless of age, but especially in the critical years of development. Any illicit (or even non-illicit) drugs have potential to alter brain development. This could lead to poorer cognition later in life and impairments in the prefrontal cortex.
  • Poor diet: Shoveling down sugar-coated cereal and refined carbohydrates each day without getting sufficient protein, veggies, fats, and fruits may create problems. Diet plays an important role in brain function and can even influence whether someone develops a mental illness. A poor diet may also affect developing brains.
  • Relationship troubles: Being in abusive relationships also isn’t healthy for us. This encourages dependence and inhibits the ability to express ourselves. In order to ensure healthy brain development, it is necessary to make healthy, positive friends and establish non-toxic relationships.
  • Sleep problems: Those that fail to get an adequate amount of sleep (in terms of quality and quantity) may have underdeveloped brains. Sleep helps ward off stress and getting enough of it is known to help promote healthy brain development. If you have any severe sleep problems and/or aren’t getting enough sleep, it may inhibit optimal brain development.
  • Social isolation: Remaining isolated from society can have profound effects on personality, mood, and our ability to perform in social situations. Those that are isolated from social contact may experience suboptimal brain development. Establishing positive social contacts is key during this period.

Final thoughts: Brain Development Continues Throughout 20s

Neuroscientists largely agree that the human brain hasn’t fully developed until (at least) the mid-20s. Although the changes that the brain incurs after adolescence are not well-studied, increases in myelination and pruning of neural pathways are believed to occur. Additionally our personality as well as development of the prefrontal cortex is finalized well into our 20s.

Although you may consider yourself an adult at age 18, keep in mind that your brain still has a ways to develop. Your cognition, ability to assess risk, and think logically will continue to improve as you age. This is considerably different than neuroscience views of the past in which we thought the brain was done developing in the teenage years.

And despite the fact that brain development may be done by our 30s, it doesn’t mean that someone with a fully developed brain cannot change it. There is considerable evidence to suggest that we can still change our own brains with a process called “neuroplasticity.” Our brains are constantly adapting to our environment, experiences, and other inputs to which it is exposed.

  • Source: http://www.nature.com/neuro/journal/v6/n3/full/nn1008.html
  • Source: http://www.jeffreyarnett.com/arnett2009theemergenceofmergingadulthood.pdf
  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621648/
  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2892678/

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{ 13 comments… add one }
  • Lisa Bryant May 27, 2015, 5:52 pm

    My how things would differ if the worldview of 22 year-old children were correct. They have no business trying to make life decisions, much less serving in the military. I could go on and on.

    • Tzipora March May 10, 2016, 8:28 am

      Does it make you feel less bitter and washed up to call all 22 year olds children? Everyone does not fall into a black and white box, from one 22 year old to one insecure woman. All you accomplished with your weak voice here was making yourself sound foolish and condescending. Very unattractive. Even a child could tell. Please do go on and on. If you do, leave the people who serve this country out of your mouth. Ungrateful and disrespectful.

  • Joseph D June 14, 2015, 6:43 am

    Lisa, I think your comment is rather ignorant. If I wished to resemble you, I would say “I Know” your opinion is ignorant. However, I hope I never resemble you throughout the duration of my entire life. Contrary to your assumption, someone’s brain being fully developed does not indicate that all of their decision making is automatically correct. In fact, we need young minds to question the status quo. I am a 21 year old college student, and find your assumption that “I have no business making life decisions” offensive.

    A bigger detriment to society are those who claim themselves “experts” or assert that “they know better”. It was only a few decades ago that brain function was thought to be completely localized (certain areas concretely relating to specific functions without fluctuation) and now the concept of neuroplasticity is universally accepted. A few decades ago there was no such thing as plate tectonics and the center of the Earth was “without a doubt” molten lava.

    Now it is understood that the very center of the Earth is solid. Henry Ford viewed anyone who considered himself an “expert” as a detriment to his innovation, and would consequently fire them. He claimed his company had not one expert among them. According to Henry Ford, “As soon as a man believes himself an expert, a great many things become impossible”. So now here I am, amused at your expert attitude. How many things you must know, and how many things you must consider to be impossible.

    Progress is not guaranteed to move forward. The second we consider ourselves “experts” we stop moving forward. There have been civilizations throughout history that have deteriorated, and I do not believe it impossible for humanity as a whole to deteriorate. The Maya, had they continued their scientific progress, would likely have landed on the moon centuries before us. Despite the economic turmoil in which Greece currently finds itself, Ancient Greece had significant scientific, philosophic, and societal achievements which echo on to this very day.

    Now I can agree that the youth are not always prudent, but the way in which the brain prioritizes what’s “important” is entirely relative to the milieu and culture it is subject to. It is because you consider the subjection of young minds to TV, Media, and Advertising normal that you consider their “inability to make decisions” normal. You should also recognize that we are growing up in a different culture than the one you grew up in, and will consequently have differing values.

    A radical idea it would be to consider NOT basing our values on what is fed to us through a screen, a paper, or a single book in isolation of all others. It also seems to me that values seem to evolve for the better with the pass of each generation, or else we would still be burning “witches”. So what are you saying? Do you believe we should not be allowed to make decisions now? Perhaps we should all just become “another brick in the wall” (a reference I imagine you can relate to).

    You’re right(sarcasm), we should all be good children, sit still, and not question the shadows of this cave we live in (a reference to Socrates in case you didn’t catch it).

    • John Smith January 6, 2016, 10:59 am

      Woman posts 3 sentences…

      21 year-old child replies with six meandering, self-important paragraphs in an attempt to belittle her with his astounding intelligence and learnedness.

      Hasn’t yet learned that “brevity is the soul of wit”.

      • Alwin Arnold March 12, 2016, 8:29 pm

        Who is belittling who? Your scorn is unwarranted.

      • Stephanie Orr March 19, 2016, 2:28 am

        Very well said.

  • Joy October 28, 2015, 9:35 pm

    This was very insightful. Thank you!

  • Darrell December 7, 2015, 4:57 pm

    Brain development is not linear. Babies, toddlers, and children develop phenomenally quickly. Youth are still developing, but most of it is there. And maturity is not a binary “mature/not mature”. We develop maturity in a lot of different aspects (muscles, patience, tact, humor…) throughout our lives. There are some extremely petulant, immature adults (politicians, anyone?). Think of it like the frequency channels we see on our stereos.

    Some bars go high (loud), others not so much. Just make sure you answer children’s questions truthfully. If you don’t know, teach them how to find out. “Smart” people are simply curious people. As evidence, I have met some very clever people with significant mental disabilities.

  • PJ February 8, 2016, 9:52 am

    Less can be more, Joseph. On the other hand, you can be relieved to know that you might outgrow that knee-jerk trigger, problem-with-perceived-authority that spawns long emotional rants in response to someone’s 3 sentence comment as you get older. Eat well, sleep well, and in a few years you may be less easily set off.

    This article was interesting, as I have seen (being old now) the very obvious changes in people from about 18 to mid-20s, greatly in the categories mentioned — impulsivity; planning; and especially in the ability to separate one’s emotional definition of self from nearly everything else, which I think I will attribute to the article’s comment on “response to peer pressure.”

    There is a great deal of ‘everything is threatening or insulting’ that is at the front during that era of many peoples’ lives that (blessedly) recedes back to a normal “it isn’t about you” status as they move toward 30.

  • Rodney "RJ" Young February 26, 2016, 5:09 pm

    These comments are hilarious!

  • B Smith May 15, 2016, 1:22 am

    I have seen many young people “mature” very rapidly when they become parents. The realization that they are “on” makes for big changes.

  • Niko May 22, 2016, 4:30 pm

    This article is so true, at least on my example. I’ve lived my life in high stress environment. I’ve started new life 500 km away at 24. I’m 26 now and I’m killing it in every aspect of my life. For a second I even thought I have a brain cancer how different I’ve become. But I did work a lot on my behavior, thinking about what I don’t like and gradually changing it.

  • Colleen May 25, 2016, 3:02 pm

    How many people actually know that the front of their brain isn’t fully mature until their mid 20s? Thank you for sharing this! It’s very interesting. We should share this information in school’s on a daily basis! God Bless.

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