Stages of Development Series: Maturity

LakeCreek Montessori School • March 5, 2025

Explore the final stage of human development (ages 18-24) through a Montessori lens—where independence, purpose, and meaningful societal contributions take shape.



This is the final post of a series focusing on each of the four stages (or planes) of development: birth through age six, ages six to twelve, ages twelve to eighteen, and ages eighteen to twenty-four. Montessori pedagogy calls for a big picture perspective that incorporates the fundamental principles of human development at each stage of development and how we can best provide for a developing young person in each stage.


A Path Toward Maturity and Contribution to Society


The journey of human development, as envisioned by Dr. Maria Montessori, is marked by four distinct planes. Each plane represents a different phase in an individual's growth, and the fourth plane, spanning from 18 to 24 years of age, is no exception. This phase, which Montessori refers to as Maturity, signals the culmination of psychological and physical growth and paves the way for young adults to step into the world as a fully formed individuals capable of significant contributions to society.


Characteristics of the Fourth Plane


The fourth plane represents a time when individuals reach the height of their development and begin to assume their role in society. Unlike the earlier planes, the psychological changes during this period are less dramatic and more internal, and the focus shifts to understanding oneself and the world beyond one’s immediate needs. Whereas the body completes its physical maturation, the mind embarks on the task of understanding how it can contribute to humanity.


In The Four Planes of Education, Dr. Montessori writes, “The individual should be the man who knows how to make his own choice of action having passed to perfection the preceding phases. He should be as a live spark and aware of the open gate to the potentialities of prospective human life and of his own possibilities and responsibilities” (p. 15). This encapsulates the essence of the fourth plane— young adults’ newfound ability to make independent choices while being aware of their potential impact on society.


In this stage, individuals are not merely focused on themselves but are also learning to engage with the world beyond their personal ego. The question that arises is not “Who am I?” but “What can I do?” This shift from self-centeredness to a broader, more collective view of life signifies the maturity that defines the fourth plane.


Conquest of Independence

One of the key aspects of the fourth plane is the conquest of independence, particularly economic independence. This phase marks a time when individuals strive to become self-sufficient within the larger society. Young adults move beyond the dependency of childhood and adolescence, assuming more responsibility for their own life, finances, and future.


This is a period when a personal mission begins to take shape. Young adults start to solidify their goals, whether academic, professional, or personal, and work toward them with a growing sense of purpose. Dr. Montessori believed that achieving economic independence was crucial, as it not only provides the means to live but also fosters a sense of autonomy and responsibility.


Observable Examples of Development


Physically, by the fourth plane, development is largely complete. The dramatic growth spurts of the previous stages have slowed, and young adults now have full mastery over their body. Health is typically stable, and there is an overall sense of well-being.


Much like the second plane, the fourth plane is also conducive to intellectual pursuits, particularly those that lead to specialization in areas essential for a future career. This is when our young adults are honing skills that will serve them in the professional world, whether through higher education, apprenticeships, or other forms of specialized learning.


The fourth plane is also a time when individuals, having developed a solid understanding of themselves, are ready to take on more significant intellectual and social responsibilities. This is when they truly start asking the big questions, such as, “How can I contribute to the world?” It is at this stage that young adults embark on the exploration of their "cosmic task," a concept Montessori introduced in the second plane, which refers to the idea that every individual has a unique role to play in the larger story of humanity.


The Role of the Supportive Environment


With significant internal growth happening during the fourth plane, the role of the external environment remains crucial. A supportive environment during the preceding planes can have a profound effect on how individuals move through this stage. If our young adults have been nurtured in an environment that promotes autonomy, responsibility, and respect for their capacity to make choices, they are more likely to enter adulthood with the skills and mindset necessary to thrive in society.

To prepare for their careers during this time, many young adults pursue higher education, either through university studies or vocational training. Alternatively, they may enter the workforce, beginning to take on professional roles that contribute to society. This is also a time when many young adults leave the family home and start families of their own, further solidifying their place in the world as independent adults.


Dr. Montessori, unfortunately, did not have the opportunity to explore this phase in depth. However, we can imagine a world where every individual has been given the best possible environment throughout the previous planes of development. In such a world, adults who emerge from the fourth plane are equipped not only with the knowledge and skills to succeed but also with a profound sense of responsibility toward the greater good.


An Enlightened Society


The ideal outcome of the fourth plane is individuals who not only seek personal success but also work toward the welfare of humankind. Young adults who have passed through the earlier planes of development with the support of nurturing environments can enter society with a strong social conscience, eager to contribute to the collective well-being of humanity. They see the interconnectedness of all people and seek ways to address societal issues and contribute to the common good.


Imagine a world in which all young adults, having been guided through the previous developmental stages, emerge from the fourth plane ready to play their roles in society—not only as self-sufficient individuals but as enlightened members of a larger human community. This vision encapsulates the Montessori ideal: a world where everyone has the potential to contribute meaningfully to the advancement of humanity as a whole.


The fourth plane of development is not merely a time for self-discovery but a time for self-realization and societal contribution. Young adults, secure in their independence, prepare to engage with the world in ways that transcend personal goals, focusing instead on broader responsibilities. By fostering an environment that nurtures growth and independence, we set the stage for a society composed of individuals capable of making meaningful contributions to humanity’s collective well-being.


Curious to see how attention to the characteristics and needs of earlier stages of development can support an enlightened society? Schedule a tour today! 



By LakeCreek Montessori School April 1, 2026
When children struggle, Montessori asks: what's in the way? Explore how the prepared environment helps children find their way back to themselves.
April 1, 2026
Discover why Montessori teaches cursive first — and how neuroscience is confirming what Dr. Montessori observed about children's hands and brains.
By LakeCreek Montessori School April 1, 2026
More Than a Chart on the Wall: How Montessori Timelines Build History, Imagination, and Character
By LakeCreek Montessori School April 1, 2026
Discover how Montessori education nurtures children's deepest human needs — from exploration and meaningful work to belonging and spiritual growth.
By LakeCreek Montessori School March 6, 2026
Discover how peer learning, meaningful context, adult interaction, and order align Montessori with the science of how children learn best.
By LakeCreek Montessori School March 6, 2026
Montessori education has been in existence for over a century, but does it actually work? Dr. Angeline Stoll Lillard spent years researching this question, and her book, Montessori: The Science Behind the Genius, is a must-read. In her book, Dr. Lillard identifies eight principles at the heart of Montessori education. What’s key is that these Montessori principles align with what developmental science tells us about how humans actually learn. The remarkable thing is that Dr. Maria Montessori arrived at most of these insights through careful observation of children, decades before the research existed to corroborate how children learn. In this two-part blog post, we’ll examine these eight principles and the connected research. PRINCIPLE ONE: Movement and Learning Are Deeply Entwined In most traditional classrooms, children are still expected to sit still, as if stillness is a prerequisite for learning. In Montessori, we understand how movement and thinking are intertwined. And research backs this up. Studies have found that physical activity improves cognition, judgment, memory, and social reasoning. Moving the body isn't a break from learning. Rather, the movement is often the learning (and this is even more so for younger children!). Montessori materials are designed to be touched, carried, sorted, and manipulated. Children working with the knobbed cylinder blocks are actively perceiving, making judgments, and reasoning through their hands. The same is true when children sort fabric squares by texture, shake and compare sound cylinders, or lay out bead bars to represent quantities. Every material helps children integrate their minds and bodies. Practical life activities take this even further. When children learn to pour, button, fold, or prepare food, they are engaging in organized sequences of purposeful action that develop concentration and executive function skills. What the Research Shows A Milwaukee study found that high school students who had previously attended Montessori programs significantly outperformed peers on math and science assessments, subjects that rely heavily on the kind of reasoning that, in Montessori, is first built through hands-on materials. PRINCIPLE TWO: Choice Improves Both Learning and Well-Being The freedom to choose is at the heart of Montessori education, but this isn’t just about enjoyment. Having choice measurably affects how well children learn and how they feel about themselves. In a striking series of studies, children aged seven to nine were given anagram puzzles to solve. Those who chose their own category of puzzle solved twice as many as children whose category had been chosen for them, even though the actual puzzles were identical. Those who had a choice also spent far more time voluntarily working on puzzles during free time. The key finding is that the perception of control (even in small things) activates a fundamentally different relationship to the work. Children who feel in control tend to engage more deeply, persist longer, and take more ownership of their learning. In a Montessori classroom, children choose their own work throughout the day. Importantly, Dr. Lillard notes that this freedom is always paired with responsibility, and that too many choices can be as demotivating as none. The Montessori environment offers meaningful, bounded choice. Rather than an overwhelming array, each classroom has a selection of purposeful materials designed to match children’s developmental readiness. Choice and concentration are closely connected, too. When children choose work that genuinely engages them, they're far more likely to reach a deep state of focus, or what psychologists call a “flow state.” PRINCIPLE THREE: Children Learn Best When They're Genuinely Interested This sounds obvious, of course! It makes sense that we learn better when we are interested. However, think about this in terms of how classrooms are typically structured. If interest is one of the most powerful drivers of learning, then organizing a school day around a single curriculum delivered to the whole class at once works against almost every child in the room. Dr. Montessori understood children's interests as biological signals pointing toward what their developing minds most need to engage with at that moment in their lives. These windows of opportunity, or "sensitive periods,” are particular stretches of development during which children are uniquely primed to absorb certain kinds of learning. During these windows, learning that matches the child's inner readiness can be extraordinarily effortless and lasting. The role of interest is why Montessori materials are designed to be beautiful, engaging, and self-correcting. The sensorial materials, for example, aren't only teaching discrimination of size or color. They are designed to help children become more interested in noticing the world around them. The adult’s role is to observe carefully and offer new lessons at the moment a child's interest is most alive. PRINCIPLE FOUR: Rewards Undermine the Motivation They're Meant to Build Offering children external rewards (e.g., stickers, prizes, praise for being smart) for activities they already enjoy reliably reduces their intrinsic motivation to do those things later. What the Research Shows Researchers identified preschoolers who loved drawing with markers. They then told one group they would receive a "Good Player Award" for drawing (a fancy certificate with a gold star). Weeks later, the children who had expected the reward used the markers far less than they had before, and half as much as children who had never been offered a reward at all. Expecting a reward had turned something they loved into something they did for a prize. And when the prize was gone, so was much of the pleasure. Rewards like sticker charts, gold stars, and even grades and honor rolls, shift children’s relationship to learning from "I do this because it interests me" to "I do this to get the reward." When the reward is taken away, children’s inner drive has often already weakened. In Montessori classrooms, feedback comes through the work itself, which includes many self-correcting materials, so children discover their own errors without external judgment. The goal is to keep children's relationship to learning intrinsic, personal, and durable. This doesn't mean feedback is absent, though! What matters is the kind of feedback. Research by psychologist Carol Dweck found that praising children for effort (e.g., "you worked really hard on that”) produces dramatically better outcomes than praising ability (e.g., “you’re so smart”). Children praised for effort choose harder challenges, persist longer after failure, and actually improve their performance over time. Children praised for their intelligence begin avoiding challenges, fearing that failure will expose them as not as smart as they were told they were. In our following blog post, we’ll look at the next four Montessori principles outlined in Dr. Angeline Stoll Lillard’s book, Montessori: The Science Behind the Genius: Children Learn Powerfully from Each Other Meaningful Context Makes Learning Richer and More Lasting How Adults Interact with Children Shapes Everything Order in the Environment Supports Order in the Mind In the meantime, schedule a tour here in North Austin to see the principles in action! And let us know if you would like to borrow a copy of Montessori: The Science Behind the Genius by Dr. Angeline Stoll Lillard. It is one of the most research-based books on Montessori education, and we recommend it to anyone who wants to understand the deeper logic of Montessori!
By LakeCreek Montessori School March 6, 2026
When we lose our cool, repair matters most. Explore accountability, curiosity, and connection to break reactive cycles and parent with intention.
By LakeCreek Montessori School March 6, 2026
Explore the Montessori three-period lesson and how its quiet simplicity unites words and meaning during a child’s sensitive period for language.
By LakeCreek Montessori School February 13, 2026
Explore a curated list of children’s books about water, rivers, and watersheds. These stories invite curiosity, care for the planet, and meaningful reading at home.
By LakeCreek Montessori School February 12, 2026
Montessori children experience long division in a concrete and meaningful way. This post shares how hands-on materials help children understand place value and build confidence with complex math.
Show More