Stern repeatedly emphasizes that one of the aims of his book is to bring together insights from two distinct fields that have views about the subjective experience of infants. The first perspective is that of the developmental psychologist who runs experiments involving infants in order to make sense of their internal subjective life and to learn more about the process of subjective development. The work of developmental psychologists generates a theoretical construct known as "the observed infant." The observed infant is the more scientifically-based, micro-level perspective that appeals to scientific studies and local organizing principles.