A
self-fulfilling prophecy is a prediction that directly or indirectly causes itself to become true, by the very terms of the prophecy itself, due to
positive feedback between belief and behavior. Although examples of such
prophecies can be found in literature as far back as
ancient Greece and
ancient India, it is 20th-century
sociologist Robert K. Merton who is credited with coining the expression "self-fulfilling prophecy" and formalizing its structure and consequences. In his 1948 article
Self-Fulfilling Prophecy, Merton defines it in the following terms: In other words, a positive or negative prophecy, strongly held belief, or
delusion—declared as truth when it is actually false—may sufficiently influence people so that their reactions ultimately fulfill the once-false prophecy.