The sequence of lessons in Montessori education follows a pattern of concrete toward abstract. Generally, the climb to abstraction opens up new concepts and skills to exercise in concrete ways, giving the sequence of concrete to abstract a recursive quality. As a person matures and their brain develops fully, the abstract tends to dominate their thinking and their work. However, most people retain a real need to continue to work in the concrete realm to a greater or lesser extent throughout their lives.
In the WLS Montessori program, in the lower elementary the children’s psychological plane generally requires them to work more extensively on a concrete level. With burgeoning abstracting power developing in the upper elementary, the children spend more of their time in the abstract realm, with there being a rough balance between concrete and abstract levels of work. In the adolescent program, the children’s psychological plane shifts dramatically toward the abstract, making them capable of very advanced abstract thinking (but note that they also have a resurgent need for work in the concrete realm: building things, growing things, and exercising intensely).
Computers are by nature abstract. When you move a mouse on a computer, the actual movement of the arrow on the screen is many abstract steps removed from your concrete act of pushing the mouse across the pad. Images on a screen are not “real”, or concrete: they are virtual; they are simulations of some other real things. For that reason, computers play a minimal role in lower elementary, if they are used by children at all (and some of us would prefer that there is no computer use by children for the greater portion of the lower elementary experience). The greater abstracting ability and need in upper elementary allow for the slightly increased use of the computer at that level: learning keyboarding, doing some word processing, doing some research on the internet, and getting some lessons in spreadsheets are all appropriate in a limited way.
In the adolescent program, computers are an important part of daily work. A student can still go through the two years of our adolescent program without using a computer, but in the interest of their preparedness for their next educational environment and their life in the modern world, we want them to have adequate skills on the computer, and will work to develop them in students in the adolescent program. The role of the computer at this level is still as a tool, though; not as an end in itself.
In essence, for philosophical reasons, we severely limit computer use by children in lower elementary. We bring computers into the routine work on a limited basis in the upper elementary. And in the adolescent program we use them whenever they are the best tool for the job, which in research, writing, video production, spreadsheet work, etc., is often the case.