Isolation of difficulty
Isolation of difficulty means building a material or a lesson so the child meets one new difficulty at a time, with everything else held the same.
The button dressing frame shows it plainly. A child getting dressed has to manage sleeves, balance, a moving body and buttons all at once. The frame takes the buttons out of the outfit and lays them flat on a table. In 1912 Montessori wrote that with the fastening frames children analyse the movements of dressing and prepare for each one separately by repeating it.
One quality per material
The sensorial materials work the same way. Her 1917 book states the rule: the objects in a series differ from each other in one and only one quality. Her bells for the ear look identical in size and shape and differ only in sound. The first cylinder block varies only in diameter. The pink cubes differ only in size, not in form.
The phrase "isolation of difficulty" itself is not in her 1912 to 1917 books (we searched all five). AMI's glossary uses "isolation of a difficulty" for the adult's side of it: analyse the activity before showing it, and teach any troublesome movement separately.
One sense at a time
The same thinking reaches the senses. The 1914 handbook says to concentrate the child's attention on one stimulus by isolating the sense: silence in the room, and a blindfold for exercises that do not concern sight.
Then the difficulty goes back in
The isolated skill does not stay isolated. The handbook describes children fastening and unfastening the same frame many times and then wanting to fasten real clothes, their own and other children's. When a child starts buttoning a cardigan without being asked, the frame has done its job.
Sources
Passage numbers point into the public-domain texts this site checks every citation against.
- The Montessori Method, Maria Montessori (1912), ch. IX, passage 39863:220: The fastening frames let children analyse the movements of dressing and prepare for them separately by repeated exercises.
- Dr. Montessori's Own Handbook, Maria Montessori (1914), Motor Education and Sensory Education, passages 29635:24, 29635:54: Children fasten the same frame many times, then want to fasten real clothes; isolate the sense with silence and a blindfold.
- The Montessori Elementary Material, Maria Montessori (1917), Part VI, passage 42869:388: Sensorial objects differ from each other in one and only one quality; the bells alike in size and shape, different in sound.
- Glossary of Montessori Terms, Association Montessori Internationale (read ): Isolation of a difficulty: the teacher analyses the activity and teaches troublesome movements separately.
To see this at work across a whole area, the practical life lessons list every lesson in order, with its age and materials.
Related terms: control of error, prepared environment, three-period lesson. All eight are in the glossary.