The perception of the form of an object by means of touch with no visual information. Dr. Montessori makes a fine distinction in describing the stereognostic sense. She tells us that this sense does not consist only of the sense of touch, because only surface qualities are perceptible to touch: rough, smooth, warm, cold. She says the perception of form comes from combined tactile and muscular sensations, muscular sensations being sensations of movement. The first plane child (0–6 years) is endowed with a special muscular sensitivity, which he enhances and refines by spontaneous touching and handling. The young child perfects his sense perceptions through his own efforts.
Dr. Montessori’s work with the intellectually impaired led her to conclude that among the various forms of sense memory, muscular memory is the earliest in appearance. Children who could not recognize a figure by looking at it could recognize it by touching it. Combing the muscular–tactile sense with vision “aids in the most remarkable way the perception of forms and fixes them in memory.” Take, for instance, the sandpaper letters. The form is taken in both visually and muscularly.
It is important to isolate the sense that we wish to refine. Thus, in all sensorial exercises involving form, we can isolate the muscular–tactile sense by removing visual information, by using a blindfold or closing one’s eyes. For an added challenge, the child can insert the cylinders or build the pink tower blindfolded. Such exercises develop an acute stereognostic sense.
One of the earliest exercises designed to develop the stereognostic sense is the Mystery bag
You might have heard of or seen Stereognostic Bags. The Mystery bag helps the child refine his or her stereognostic sense or ones ability to identify objects based on touch alone (without seeing them).
When the activity is presented to the child all the materials are taken out of the bag and examined. Then all the shapes are placed back in the bag. One shape is pulled out and then you have to find the matching pair just by touch.
You can create this simple activity at your home. All you need is a small bag with an opening wide enough to just allow your child to probe within with his or her hands without being able to see them. Please take necessary precautions to ensure that the objects are not small enough for the child to ingest. The mystery bag can be used to develop language, or be used as a sensorial tool to develop the child’s stereognostic (three dimensional) senses, and to reinforce object permanence.
At first, place only a few familiar objects into the bag, such as a large rock, a piece of bark, and a leaf or fresh picked flower. Though related, the objects are different in size, texture, etc. Please note you are not limited to pick objects that are related.
Here is an idea on how you can work with your toddler using the Mystery bag:
Sit down with your child. “This is the mystery bag.”
Open the bag a remove one object at a time, name it and set it down forming a vertical line.
“Let’s put them back now, would you give me the ….?” Or “Which object is smooth?”
Continue until all items have been replaced again
Close the bag slightly, insert your hand and visibly ponder about the identity of the object you grasp.
Try to give your child an idea of guessing. “I think maybe I have a ….” Or “This object is rough.”
Remove your hand from the bag with object in it. Hold the object up for the child to see first and let your child verify your guess.
Then agree with with your child.
“Now would you like a turn to guess? What are you going to take out of the mystery bag?
There are many different variations to this work. This is one of the great things about Montessori — the children get to practice the same skill over and over, but in a variety of interesting ways. An older child, who is more advanced, could try, exploring the bag blind folded, record what is found on lined paper, or draw word cards from the bag, then match the card to the object.Once you begin to explore the Mystery Bag, you will find infinite possibilities for ways to use it in your home!