Newborns display a wide variety of reflexes. In the early weeks, babies frequently move in and out of different states of arousal, although they spend the most time asleep, including important REM sleep, which stimulates the brain. Crying is the first way that babies communicate. With experience, parents become better at interpreting the meaning of the infant's cries. Newborns' senses of touch, taste, smell, and sound are well developed.
Vision is the least mature sensory capacity.
The baby's many capacities have been put together into tests that permit the behavioral assessment of the newborn. The baby's arrival is exciting, but it brings with it profound changes. Special interventions exist to ease the transition to parenthood. Husbands and wives who support each other in their new roles typically adjust well.