The role of socialization in the development of human mentality and human behaviour may be shown by citing the two cases of Anna and Isabelle

(1) Anna, an illegitimate child, was caused to be kept all alone in an upstairs room. When removed from the room at the age of nearly six years, Anna could not talk, walk or do anything that showed intelligence. She was expressionless and indifferent to everything. She could not make any move in her own behalf. This shows that in the absence of socialization the purely biological resources are too poor to contribute to the development of a complete personality. Communicative contact is the core of socialization.

(2) Isabelle was found at the age of six and a half years. Like Anna she was an illegitimate child and had been kept in isolation for that reason. When found she was apparently utterly unaware of relationships of any kind. Her behaviour was comparable to that of a child of six months. Later attempts were made to teach her to speak. At first the task seemed hopeless but lately she responded and ultimately reached the normal level of development by the time she was eight and a half years old.

Isabelle’s case shows that isolation upto the age of six with failure to acquire any form of speech does not preclude the subsequent acquisition of it. But what would be the maximum age at which a person could remain isolated and still retain the capacity for full cultural acquisition is hard to say. Both these cases, however, show the role of socialization in personality development. Through them it is possible “to observe concretely separated two factors in the development of human personality which are otherwise only analytically separated, the biogenic and the sociogenic factors.” According to La- Piereand Fransworth, “The term personality has come into scientific usage to designate the product of socialization as of any given moment with any given individual. It refers to the ‘whole’ of what the individual has acquired through socialization.” In short, socialization is the most important factor in personality development.