In<unk> theory psychology,<unk> is a product of the activity of a number of behavioral systems that have proximity to a person, e.g. a mother, as a predictable outcome. The concept of there being an<unk> " behavior, stage, and process, to which a growing person remains in proximity to another was developed beginning in 1956 by British developmental psychologist John Bowlby.  According to Bowlby, the concept of proximity<unk> has its origins in Charles Darwin's 1856 Origin of Species, which "sees instinctive behavior as the outcome of behavioral structures that are activated by certain conditions and terminated by other conditions", Sigmund Freud's 1905 Three Essays on the Theory of Sexuality and his 1915 Instinct and Their Vicissitudes, which according to Bowlby "postulates part-instincts, differentiates the aim of an instinct, namely the conditions that terminate instinctive behavior, and its function, and notes how labile are the objects towards which any particular sort of instinctive behavior is directed”, and Konrad Lorenz's 1937 theory of imprinting.  Although the term<unk> ” is still used in many areas of study, e.g.<unk> in children,<unk> in adults, reactive<unk> disorder, etc., the more chemically-correct term “bonding” is slowly beginning to replace the latter.  The 2001 book The Ontogeny of Human Bonding Systems by American transactional psychologists Warren B. Miller and Joseph L. Rodgers, for instance, is a modern-day spin-off of Bowlby’s Part IV: Ontogeny of Human<unk> in Volume I of his three-volume<unk> series books.<unk> theory is concerned with the bond that develops between child and caretaker and the consequences this has for the child's emerging self-concept and developing view of the socialworld. Bowlby's theory (1982, 1973, 1980), which was the first formal statement of<unk> theory, is an evolutionary-ethological approach (Ainsworth et al., 1978). According to this view, infant<unk> behaviors are controlled by a distinct, goal-corrected behavioral system, which has a "set goal" of maintaining proximity to a nurturing adult and a biological function of promoting the child's security and survival (Bowlby, 1982).
Attachment 
Exaptation
Dissociation 
Withdrawal
Accommodation 
Affectional bond
Derealization
Emotional contagion