Sensitive periods, refers to times in our lives when we are biologically primed to respond to certain influences in our environment. Montessori believed that the most critical times were from infancy to the age of 6. She believed that the period was transient, and limited to acquiring a particular trait. Once acquired, the specific sensibility disappeared.
Sensitive periods are critical for growth and development. They allow the child to connect with the environment in an intense and profitable manner. These stages are both selective and limited. For example, during the sensitive period for language, its selective power allows the child to filter all other audible stimuli and attend to human language. This is not done consciously. Yet, by the age of 2-3 the child has mastered language. Sensitive periods are limited by time. Once the period had passed the individual may still acquire a new language, but never with as much ease and fluency.
Missing a sensitive period has been compared to likes of a dropped stitch, the fabric still continues to exist, but it is flawed and has been weakened. A child will still grow up without having made use of a sensitive period in his/her development, but he/she will be of no comparison to what he/she may have been. We have seen this, unfortunately, with feral children. One famous case is that of Genie. A girl who was discovered at the age of 13 and due to extensive abuse was never exposed to language. With the help of many specialists she was able and eager to learn vast amounts of vocabulary but she was never able to grasp grammar and syntax. This made communication difficult and frustrating for Genie and resulting from her subsequent placements in foster care and adult wards, it has been reported that Genie is once again speechless1.
There are different sensitive periods for language, movement, order and exploration. A vast amount of research has validated these critical periods