The physical and social environment of the nursery is a direct and indirect influence on the development of premature infants. Qualities in the environment affect physiological stability and provide sensory experience that is relevant to brain development. Adaptation of the prematurely born infant to the unexpected surroundings of the neonatal intensive care unit can be facilitated when the infant's developmental needs are understood and characteristics of the environment are adapted accordingly. The need for environmental change is revealed by the infant's behaviour, that is, his interactions with the environment. The environment also affects the behaviour of caregivers, who like the baby need to be able to do their best in this challenging situation.