If they are neglectful, or perhaps even abusive, the infant instead learns mistrust- that the world is in an undependable, unpredictable, and possibly a dangerous place.
Trust as defined by Erikson is "an essential truthfulness of others as well as a fundamental sense of one's own trustworthiness." The infant depends on the parents, especially the mother, for sustenance and comfort.
The child's relative understanding of world and society come from the parents and their interaction with the child.
Thus, family is the first and most intimate social unit, which plays its important role in the socialization of the child.
Family acts as a medium for transmitting vocational knowledge and technical skill to children.