Attachment theory has also acknowledged the feeling of security made possible by healthy infant-parent relationships. In infancy, security means that the baby feels confident of the parents' availability and responsiveness. This confidence is essential to the child's development, allowing securely attached infants to explore their environments with the assurance that they can return to the parent, a safe haven, if threatened. Insecurely attached infants are those who feel uncertain that their parents will respond quickly and appropriately to their needs for nurturance, whether physical or emotional. Therefore, early attachment serves a fundamentally crucial function in individual development by establishing a sense of security that permits the infant to experience the environment without fear of being isolated or separated from nurturing parents.
Attachment occurs between two individuals.
Consequently, both the infant and the parent contribute to the characteristics of the attachment that is formed. Each infant brings to the relationship general competencies such as reflexes, senses, states of consciousness, resiliency, and habituation. The infant also possesses individual differences. These may include health conditions, temperament, and physical development. Likewise, the individuality of parents also impacts the relationship.