Parents use various sensorimotor means to interact with the child; touch and visual contact being the most powerful for communicating with an infant. Crying, smiling, grasping, reaching out, and establishing visual contact are among the attachment behaviours that infants display to maintain proximity with their parents and express their needs. A passive infant, one who seldom cries, never smiles, or resists physical contact, will require a greater investment from the parents for an affective bond to develop.