The word "sensitive" literally means "sensitive." The sensitive period is the age period in a person's life, characterized by special sensitivity to certain influences.
The possibilities for the formation and development of the psyche cannot be called unlimited: for the formation of each mental function, nature has strictly measured the time. If a child for some reason (for example, due to hearing loss) did not learn to speak before the age of 5, it is almost impossible to develop his speech later, even if hearing is restored. It is extremely difficult for a person who became blind in infancy and saw his sight in adulthood to learn to “use” vision.
In all the above examples, the time was missed when favorable conditions for the formation of the corresponding functions took place in the body as a whole and in the central nervous system in particular. When this time passed, external influences no longer had any special meaning - the nervous system could not "respond" to them.
Each sensitive period corresponds to certain mental neoplasms - those functions and properties that did not exist before. The appearance of neoplasms is a qualitative leap in mental development. The conditions for such a leap are created by the maturation of the corresponding parts of the brain and functional organs. But these conditions will remain an unrealized opportunity if they do not meet an "answer" from the environment in which the child develops.
One of the conditions for mental development is the placement of the child in a social situation corresponding to the sensitive period. For example, the age from 7 to 10 years old is sensitive for the formation of arbitrary behavior, attention and other mental processes. The appropriate external conditions are created by school education with its requirements.
Development is disrupted if the environment does not match the capabilities of the sensitive period. For example, the age from 1, 5 to 2, 5 years is especially favorable for the assimilation of language norms. If at this time adults continue to "lisp", talking with the child in a special "childish" language, repeating the "words" invented by him, this can cause a delay in speech development. The correct development of speech both during this period and in the future is facilitated by the correct, competent speech of adults, which the child should hear.
Another important condition for mental development is the child's inclusion in activities corresponding to the sensitive period. For example, for a teenager, social interaction with peers is normally the leading activity. If a teenager, under pressure from adults, continues to focus on school at the expense of communication, in the future he may experience difficulties in establishing social contacts, even as an adult.
The most striking example of the omission of sensitive periods of development is the tragedies of the "Mowgli children". Specifically human mental functions in these children could be formed very limitedly or even failed at all, since the sensitive periods of the formation of these functions have already passed.
