Secondary circular reaction
By the third month of life, a child enters a cognitive stage identified by Piaget as primary circular reaction. During this time, the infant explores objects by grasping them with the hands or by mouthing them. Infants appear to be unaware of what actions they can cause or what actions occur independently, however. At about 6 months of age infants pass into a stage Piaget called secondary circular reaction. Now when infants reach for an object, hit it, and watch it move, they realize it was their hand that initiated the motion, and so they hit it again. By 10 months, infants discover object permanence. Infants are ready for peek-a-boo once they have gained this concept. They know their parent still exists even when hiding behind a hand or blanket and wait excitedly for the parent to reappear. Binocular vision, which is the ability to fuse two images into one, is demonstrated by 2-month-olds when the follow moving objects with their eyes, although not past the midline.
The infant says "da-da" when looking at her father
By 9 months, an infant usually speaks a first word: "da-da" or "ba-ba." The other answers refer to earlier milestones in language development. In response to a nodding, smiling face, or a friendly tone of voice, a 3-month-old infant will squeal with pleasure or laugh out loud. By 4 months, infants are very "talkative," cooing, babbling, and gurgling when spoken to. At 6 months, infants learn the art of imitating. They may imitate a parent's cough, for example, or say "Oh!" as a way of attracting attention.
Be sure to wash the infant's face, hands, and diaper area daily
Except in very hot weather, an infant does not need a bath every day. If a parent is tired and would not enjoy bath time or if some days are just too rushed, a complete bath can be omitted, with only the infant's face, hands, and diaper area washed. Some infants do need their head and scalp washed frequently (every day or every other day) to prevent seborrhea, a scaly scalp condition often called cradle cap. If seborrhea lesions do develop, they adhere to the scalp in yellow, crusty patches. The skin beneath them may be slightly erythematous. The patches can be softened by oiling the scalp with mineral oil or petroleum jelly and leaving it on overnight. The crusts can then be removed by shampooing the hair the next morning. A soft toothbrush or fine-toothed comb can be used to help remove them.