The pioneering work of R. Spitz, J. Bowlby, and T.B. Brazelton revealed just how vital the social and emotional environment is for the young child. Newborns are primarily capable of relying on their social environment, eliciting from their caregivers the behaviors necessary for their development, and gathering useful information to guide their own behaviors. A baby just a few months old not only has expectations about the physical world but also has specific expectations regarding the behavior of others.