The child does not grow uniformly and homogeneously like a crystal or a carrot, but by stages or phases, which succeed one another and which, differ from one another. For proper growth and development it is necessary that the potentialities for developing human relationships with which the infant is born be exposed to the organizing influences of another human being. Accumulating evidence indicates that there exist critical developmental periods during which the organism is ready for differential development, within which periods it must receive the proper stimulations if it is to develop adequately. These critical developmental periods may be broadly outlined as follows:1)The period during which the infant is in process of establishing an explicit cooperative relationship with a clearly defined person, the mother; this is normally achieved by five or six months. 2)The period during which the child needs the mother as an ever-present support and companion; this normally continues to about the end of the third year.3)The period during which the child is in process of becoming able to maintain a fourth and fifth years, under favorable conditions, such a relationship can be maintained for a few days or even a few weeks; after seven or eight years of age such a relationship can be maintained for longer periods, though not without some strain. The capacity whereby the child simultaneously develops his own ego and super-ego and the capacity to maintain relationships with removed objects is variously described as identification, internalization, or introjection, sinceit is according to the pattern set by the parents that the functions of the ego and super-ego are incorporated within the self.The evidence supports the existence of these three critical developmental periods and we find, that three somewhat different experiences can produce the lack-love syndrome, as follows:1)Lack of any opportunity to develop attachment to a mother-figur...
