Montessori and Executive Function: Three Studies, Three Answers

Does Montessori education build executive function? Three good studies give three different answers, and the differences are the useful part.

"Montessori builds self-regulation" is a sentence I have said many times. It appears in school brochures, in training courses and in most conversations with prospective parents. When I started reading the research behind it, I expected to find it confirmed. I found something more useful: a sentence I can defend, and it is not quite the same one.

Executive functions are the mental skills that let us manage ourselves: holding information in mind while we use it, stopping an impulse, and switching attention when the situation changes. In a Children's House they look like a four-year-old who carries a tray across the room without being distracted, waits for a material that is in use, and returns to her work after an interruption. They predict a great deal about later school life, which is why researchers care whether a preschool can strengthen them.

Three studies shaped how I now talk about this.

1. Lillard and Else-Quest (2006): the question can be studied fairly

What they did. The hardest problem in Montessori research is that families choose Montessori. Parents who seek it out may differ from those who do not, so any difference in the children could come from home. Lillard and Else-Quest worked around this with a public Montessori school in Milwaukee that admitted children by lottery. They compared children who won a place with children who entered the lottery and lost. Both groups had parents who wanted Montessori.

What they found. At age five, the Montessori children did better on a measure of executive function, along with early reading and maths and several social measures. The study also looked at twelve-year-olds, where the differences were mainly in writing and social outcomes.

What it taught me. That this question can be asked seriously, with a fair comparison group, in a public school. It is one school and a modest sample, published as a short report. It does not settle anything on its own. But it moved the conversation from testimony to evidence.

2. Lillard (2012): "Montessori" is not one thing

What she did. The name Montessori is not protected, so two schools using it can look very different. Lillard compared three kinds of preschool classroom: classic Montessori, using the full set of Montessori materials and long work periods; supplemented Montessori, where Montessori materials sat alongside conventional activities; and conventional programmes. She measured the children at the start and end of a school year.

What she found. Children in the classic Montessori classrooms showed larger gains across the year than children in the other two groups, on executive function and on several academic and social measures. The supplemented classrooms did not show the same advantage.

What it taught me. That the question "does Montessori work?" is incomplete. Which Montessori? The children were not randomly assigned here, so the design is weaker than a lottery. Still, the pattern points to something practitioners recognise: the three-hour work cycle, the full range of materials and the mixed-age group work together. Remove parts and you may be removing the mechanism.

3. Courtier et al. (2021): the effect is not guaranteed

What they did. This is the study I most want Montessori educators to read, because it does not tell us what we hope to hear. In a French public preschool serving a disadvantaged neighbourhood, children were randomly assigned to Montessori or conventional classrooms. The Montessori classrooms were adapted to the constraints of the public system.

What they found. By the end of preschool the Montessori children were ahead in reading. On executive function, mathematics and social skills, the two groups did not differ.

What it taught me. That I should say so. A randomized study is the strongest design of the three, and on executive function it found no advantage. The authors note that the Montessori implementation was adapted, which connects directly to the 2012 finding about fidelity. That is a reasonable explanation. It is also the explanation we would prefer, so it deserves caution.

What I say now

I no longer say "Montessori builds self-regulation" as a fact about the method. I say that a well-implemented Montessori environment gives children daily practice in exactly the skills that make up self-regulation, and that the best studies suggest this can show up in measurable ways, though not always.

For a guide or a head of school, the practical consequence is to stop treating the name as the guarantee. If fidelity is what separates the second study from the third, then the questions that matter are concrete:

• Is the work cycle long and uninterrupted in practice, or only on the timetable?

• Do children choose their work, or are they directed to it most of the morning?

• Is the full sequence of materials available and in use?

• How often does an adult break a child's concentration with help nobody asked for?

Those are things we can observe in our own classrooms this week. The research cannot tell us how our environment is doing. It tells us what to look at.

This matters even more for children who find self-regulation hardest. As I wrote last month, the research on ADHD in Montessori classrooms is thin, and the executive function studies above were not designed for those children. A less exciting sentence is the one I can defend, and I would rather give parents that one.

References

Courtier, P., Gardes, M.-L., Van der Henst, J.-B., Noveck, I. A., Croset, M.-C., Epinat-Duclos, J., Léone, J., & Prado, J. (2021). Effects of Montessori education on the academic, cognitive, and social development of disadvantaged preschoolers: A randomized controlled study in the French public-school system. Child Development, 92(5), 2069–2088.

Diamond, A., & Lee, K. (2011). Interventions shown to aid executive function development in children 4 to 12 years old. Science, 333(6045), 959–964.

Lillard, A. S. (2012). Preschool children's development in classic Montessori, supplemented Montessori, and conventional programs. Journal of School Psychology, 50(3), 379–401.

Lillard, A. S., & Else-Quest, N. (2006). Evaluating Montessori education. Science, 313(5795), 1893–1894.