In the laboratory, researchers dream of the situation: every possible variable in their experiment is the same, except the one they wish to measure. That is how they are able to draw accurate conclusions. The Montessori materials provide that laboratory for the child, isolating a different variable in each materiel and controlling all other possibilities. A child can conduct experiment after experiment on a material, such as the pink tower, eventually discovering for him or herself the concept of larger and smaller.

This could not be a true experiment if someone had told the child before hand that each cube was larger than the next, or if the child needed to go ask a teacher if they had gotten the “right” answer when finished. Instead, the materials are specifically designed so that they fit together in only one way, offering a neutral control for the child’s experiment. This control of error makes the child’s work truly experimentation, and his or her understanding a true discovery.

Control of error is important, because research shows that discovery learning is more successful than traditional methods, when the child is prepared for discovery (Alfieri, Brooks, Aldrich, & Tenenbaum, 2011). A recent analysis of 164 studies on discovery learning found that, to be successful, there is a “general need for learners to be redirected, to some extent, when they are mis-constructing”. Montessori agrees, stating that “the power to make progress comes in large measure from having freedom and an assured path on which to go; but to this must also be added some way of knowing if, and when, we have left the path” (Montessori, 1995, p. 248). The control of error in the Montessori materials provides the feedback, seamlessly redirecting the child to the correct path. This allows the child to be truly successful at discovering for him or herself.

Control of error offers something else, as well. It offers neutral feedback. Too often, feedback, correction and education in general are mixed with messages about self-worth and self-esteem. This blurring of lines is worrisome, because a great deal of research has found that is damaging to shame a child for getting wrong answers, and only slightly less damaging to praise for correct answers. If we want children to feel free to try, fail, and try again on their path to discovery, we need their failures to be free of judgements. Yet it is nearly impossible for a human to provide truly neutral feedback. A wooden set of blocks and cylinders, however, can be more neutral than a poker champion. The materials offer the feedback the child needs to be successful, without the dangerous implications for the child’s self-worth.

The control of error in the Montessori materials provides the child with a perfect laboratory. Montessori points out that the carefully designed classroom “makes a child use his reason, critical faculty, and his ever increasing capacity for drawing distinctions” (Montessori, 1967, p. 103). Here, learning can be what it should be – experimentation, observation, feedback, more experimentation, and eventually discoveries. The child is freed from fear of mistakes and allowed to simply learn.


Alfieri, L.; Brooks, P. J.; Aldrich, N. J.; Tenenbaum, H. R. (2011). Does discovery-based instruction enhance learning? Journal of Educational Psychology, 103 (1), 1-18. doi: 10.1037/a0021017

Montessori, M. (1995). The Absorbent Mind. New York: Holt.

Montessori, M. (1967). The Discovery of the Child. New York: Random House.