These sterile environments lacked visual and tactile stimulation and although they had adequate care in the strict sense, human contact was notably absent. A significant percentage of these babies died in the first year. In the early 1950's Harry Harlow experimented with social isolation in newborn monkeys which extended from birth to as long as one year. These monkeys were severely socially impaired as a result of the isolation. Such vulnerability was not detected when older animals were isolated.
Babies gain knowledge about objects from their experiences with the mother.
If young children are deprived of a nurturing environment, such as in the case of an alcoholic or abusive parent, infants learn that objects come and go unpredictably. A colleague, Arnold Modell, went one step further by stating the capacity to know and the capacity to love are not separate functions. While the pre-programmed information for grasping, sucking and orienting toward human faces are instinctual requirements for Piaget's developmental theories, they may become impaired through neglect and abuse by caregivers. Reality is constructed from what we know and what we value as important from experiences occurring at a very early age. In the developmental model, natural selection has encouraged the brain to be flexible at certain key periods rather than emphasizing an assessment of the environment.