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Why We Should Stop Segregating Children by Age: Part I

Children learn by playing in the zone of proximal development.

One of the oddest—and in my view most harmful—aspects our treatment of children today is our penchant for segregating them into separate groups by age. We do that not only in schools, but increasingly in out-of-school settings as well. In doing so, we deprive children of a valuable component of their natural means of self-education.

The age-segregated mode of schooling became dominant at about the same time in history when the assembly-line approach to manufacturing became dominant. The implicit analogy is pretty obvious. The graded school system treats children as if they are items on an assembly line, moving from stop to stop (grade to grade) along a conveyor belt, all at the same speed. At each stop a factory worker (teacher) adds some new component (unit of knowledge) to the product. At the end of the line, the factory spits out complete, new, adult human beings, all built to the specifications of the manufacturers (the professional educators).

Of course, everyone who has ever had or known a child, including everyone who works in our age-graded schools, knows that this assembly-line view of child development is completely false. Children are not passive products to which we can add components. Children are not incomplete adults that need to be built bit by bit in some ordered sequence. Children are complete human beings in their own right, who constantly demand to control their own lives and who, despite what we put them through, insist on learning what they want to learn and practicing the skills they want to practice. We can't stop them. We would all be much better off if we went with them on this rather than fought them.

In previous postings I have described settings where children educate themselves, without adult direction or prodding. In particular, I have discussed self-education as it once occurred in hunter-gatherer bands (August 2, 2008 posting) and as it occurs today in schools designed for self-education, particularly the Sudbury Valley School (August 13, 2008 and September 3, 2008 postings). A prominent feature of such settings is that children regularly interact with others across the whole spectrum of ages. Anthropologists have claimed that free age mixing is the key to the self-education of hunter-gatherer children; and Daniel Greenberg has long claimed that free age mixing is the key to self-education at the Sudbury Valley School, which he helped to found [1].

Several years ago, Jay Feldman (who then was a graduate student working with me) and I conducted some studies of age-mixed interactions at the Sudbury Valley School, aimed at (a) determining how much age mixing occurred at the school, (b) identifying the contexts in which age-mixing occurred, and (c) identifying ways by which age mixing seemed to contribute to students' self-education.

When given a choice, children spend considerable time interacting with others who are older or younger than themselves.

Sudbury Valley has, at any given time, approximately 170 to 200 students, who range in age from 4 to 18 years old and sometimes older. Students can move freely at all times throughout the school buildings and campus, and they can interact with whomever they please. The school is large enough that students could, if they chose, interact just with others who are within a year or two of themselves in age. But they don't do that. In our quantitative study we found that more than 50% of students' social interactions at the school were with other students who were more than two years older or younger than themselves, and 25% of their interactions were with other students who were more than 4 years older or younger than themselves [2]. Age mixing was especially frequent during play. Active play of all sorts was more likely to be age mixed than was conversation that did not involve play.

Over the next several installments of this blog, I will discuss various advantages of an age-mixed environment for self-education, using examples from our observations at Sudbury Valley [3]. One clear advantage, and the topic of this rest of today's installment, is this:

Age mixing allows younger children to engage in, and learn from, activities that they could not do alone or only with age-mates.

In the 1930s, the Russian developmental psychologist Lev Vygotsky developed a concept that he called the zone of proximal development, defined as the realm of activities that a child can accomplish in collaboration with more skilled others but cannot accomplish alone or with others who are at his or her same level [4]. Vygotsky claimed that children learn best when they are engaged with more skilled others within their zones of proximal development. Since Vygotsky's time, education professors have often used Vygotsky's concept to describe interactions between adult teachers and young learners, but the concept applies far better, I think, to naturally occurring age-mixed interactions among children.

As an illustration (which I have used elsewhere), imagine two 4-year-olds trying to play a simple game of catch [5]. They can't do it. Neither child can throw the ball straight enough for the other to catch it, so the game is no fun and quickly dissolves. Now imagine a 4-year-old playing catch with a skilled 8-year-old. The older child, by diving and leaping, can catch the wild throws of the younger one and can have fun doing it; and the older child can lob the ball directly into the outstretched hands of the younger one, so the latter can experience the joy of catching. Thus, catch is a game within the 4-year-old's zone of proximal development. In an age-segregated environment consisting of only 4-year-olds, there would be no catch; but in an age-mixed environment that includes some 8-year-olds as well as 4-year-olds, catch is within everyone's realm of possibility.

At any given time of day at Sudbury Valley you can find young children playing games, with older children, that they would not be able to play just with age-mates. These include intellectual games as well as athletic ones. They play together not because anyone requires them to, but because they want to. Younger children are attracted to the activities and personalities of older ones, and older children enjoy opportunities to interact with younger ones.

Here's an example of intellectual play in the zone of proximal development. In several instances we observed 7- or 8-year-olds playing complicated card games in groups with older children and teenagers. By themselves, 7- and 8-year-olds would not be able to play such games. They would not be able to keep their attention focused long enough, or keep track of the rules, or even hold their cards straight enough to keep others from seeing them. They could play the games with older children because the older ones kept them on track, reminded them when necessary of what they had to do, and sometimes gave them strategy hints: "Pay attention." "Try to remember which cards were played." "Think before you lay down a card, so you don't put down something another player can take." Attention, memory, and forethought are the elements of what we commonly call intelligence. In the process of playing cards, which they were only doing to have fun, the older children were incidentally helping the younger ones to develop their intelligence.

Vygotsky's concept also helps us understand how young children learn to read at Sudbury Valley. Children who can't read, or can't read well, can regularly be found playing games (especially computer games) that involve the written word with children who can read well. The readers read aloud what the others cannot, and in the process the non-readers gradually become readers themselves.

Age mixing also allows young children to engage in playful adventures that would be too dangerous for them to do alone or just with age mates. Children who would, quite appropriately, be too frightened to venture off into the woods by themselves feel safe doing so with older children, who know the woods. Similarly, little kids new to tree climbing feel safe venturing up onto some of the lower branches if big kids are under them, advising them how to do it, ready to catch them if they fall.

When you are little and just with kids your own age, the range of possible activities is restricted by the knowledge and abilities of those in your age group; but in collaboration with older kids there is almost no limit to what you might do!
In the next several installments I will describe more advantages of an age-mixed educational environment, including advantages for the older children as well as the younger ones.


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1. Greenberg, D. (1992). Sudbury Valley's secret weapon: Allowing people of different ages to mix freely at school. In D. Greenberg (Ed.), The Sudbury Valley School experience, 3rd ed. Framingham, MA: Sudbury Valley School Press.
2. Gray, P. and Feldman, J. (1997). Patterns of age mixing and gender mixing among children and adolescents at an ungraded democratic school. Merrill-Palmer Quarterly, 43, 67-86.
3. Gray, P. and Feldman, J. (2004). Playing in the Zone of Proximal Development: Qualities of Self-Directed Age Mixing Between Adolescents and Young Children at a Democratic School. American Journal of Education, 110, 108-145.
4. Vygotsky, L. (1978). Interaction between learning and development. In M. Cole, V. John-Steiner, S. Scribner, and E. Souberman (Eds), Mind and society: the development of higher psychological processes. Cambridge, MA: Harvard University Press.
5. Gray, P. The value of age-mixed play. Education Week, April 16, 2008.

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