Developmental psychology
Attachment theory, originally developed by John Bowlby, focuses on the importance of open, intimate, emotionally meaningful relationships. Attachment is described as a biological system or powerful survival impulse that evolved to ensure the survival of the infant. A child who is threatened or stressed will move toward caregivers who create a sense of physical, emotional and psychological safety for the individual. Attachment feeds on body contact and familiarity. Later Mary Ainsworth developed the Strange Situation protocol and the concept of the secure base.
Applied psychology
The founder of applied psychology was Hugo Münsterberg. He came to America (Harvard) from Germany (Berlin, Laboratory of Stern), invited by William James, and, like many aspiring psychologists during the late 19th century, originally studied philosophy. Münsterberg had many interests in the field of psychology such as purposive psychology, social psychology and forensic psychology. In 1907 he wrote several magazine articles concerning legal aspects of testimony, confessions and courtroom procedures, which eventually developed into his book, "On the Witness Stand". The following year the Division of Applied Psychology was adjoined to the Harvard Psychological Laboratory. Within 9 years he had contributed eight books in English, applying psychology to education, industrial efficiency, business and teaching. Eventually Hugo Münsterberg and his contributions would define him as the creator of applied psychology. In 1920, the International Association of Applied Psychology (IAAP) was founded, as the first international scholarly society within the field of psychology.