34 objects and develops a rudimentary understanding of their properties. Infants develop object permanence toward the end of the first year. - The emergence of symbolic thought is central to cognitive development. This results in the ability to understand and produce language. Social Development The most important social task is the development of attachment to the primary caretaker, most often the child's mother. The child develops affectionate and trusting relationships with other family members and with adults outside the family. The child can also be engaged in simple games and play.