The emotional bond that typically forms between infant and caregiver is the means by which the helpless infant gets primary needs met. It then becomes the engine of subsequent social, emotional, and cognitive development. The early experience of the infant stimulates growth of the brain and shapes emerging mental processes. It establishes in the infant's brain the neural pathways that will sculpt what are likely to be lifelong patterns of response to many things.
The attachment experience affects personality development and the ability to form stable relationships throughout life. Neuroscientists believe that attachment is such a primal need that there are networks of neurons in the brain dedicated to setting it in motion, and the process of forming lasting bonds is powered in part by the hormone oxytocin.
The genius of the attachment system is that it provides the infant's first coping system, the one that is a foundation for all the others; it sets up in the infant's mind a mental representation of the caregiver, one that is wholly portable and can be summoned up as a comforting mental presence in difficult moments. Attachment contains within it the platform for the child's ability to ultimately separate from the caregiver and to survive independently.