Merton's concept of the self-fulfilling prophecy stems from the Thomas theorem, which states that "If men define situations as real, they are real in their consequences". According to Thomas, people react not only to the situations they are in, but also, and often primarily, to the way they perceive the situations and to the meaning they assign to these perceptions. Therefore, their behaviour is determined in part by their perception and the meaning they ascribe to the situations they are in, rather than by the situations themselves. Once people convince themselves that a situation really has a certain meaning, regardless of whether it actually does, they will take very real actions in consequence.
Merton took the concept a step further and applied it to recent social phenomena. In his book Social Theory and Social Structure, he conceives of a bank run at the fictional Last National Bank, over which Cartwright Millingville presides. It is a typical bank, and Millingville has run it honestly and quite properly. As a result, like all banks, it has some liquid assets (cash), but most of its assets are invested in various ventures. Then one day, a large number of customers comes to the bank at once—the exact reason is never made clear. Customers, seeing so many others at the bank, begin to worry. False rumours spread that something is wrong with the bank and more customers rush to the bank to try to get some of their money out while they still can. The number of customers at the bank increases, as does their annoyance and excitement, which in turn fuels the false rumours of the bank's insolvency and upcoming bankruptcy, causing more customers to come and try to withdraw their money. At the beginning of the day—the last one for Millingville's bank—the bank was not insolvent. But the rumour of insolvency caused a sudden demand of withdrawal of too many customers, which could not be answered, causing the bank to become insolvent and declare bankruptcy. Merton concludes this example with the following analysis:
The parable tells us that public definitions of a situation (prophecies or predictions) become an integral part of the situation and thus affect subsequent developments. This is peculiar to human affairs. It is not found in the world of nature, untouched by human hands. Predictions of the return of Halley's comet do not influence its orbit. But the rumoured insolvency of Millingville's bank did affect the actual outcome. The prophecy of collapse led to its own fulfilment.
Merton concluded that the only way to break the cycle of self-fulfilling prophecy is by redefining the propositions on which its false assumptions are originally based.
In economic "expectations models" of inflation, peoples' expectations of future inflation lead them to spend more today and demand higher nominal interest rates for any savings, since they expect that prices will be rising. This demand for higher nominal interest rates and increased spending in the present, in turn, create inflationary pressure and can cause inflation even if the expectations of future inflation are unfounded. The expectations theory of inflation played a large role in Paul Volcker's actions during his tenure as the Chairman of the Federal Reserve in combating the "stagflation" of the 1970s.
Philosopher Karl Popper called the self-fulfilling prophecy the Oedipus effect:
One of the ideas I had discussed in The Poverty of Historicism was the influence of a prediction upon the event predicted. I had called this the "Oedipus effect", because the oracle played a most important role in the sequence of events which led to the fulfilment of its prophecy. … For a time I thought that the existence of the Oedipus effect distinguished the social from the natural sciences. But in biology, too—even in molecular biology—expectations often play a role in bringing about what has been expected.
An early precursor of the concept appears in Edward Gibbon's Decline and Fall of the Roman Empire: "During many ages, the prediction, as it is usual, contributed to its own accomplishment" (chapter I, part II).
Examples abound in studies of cognitive dissonance theory and the related self-perception theory; people will often change their attitudes to come into line with what they profess publicly.
In the United States the concept was broadly and consistently applied in the field of public education reform, following the "War on Poverty". Theodore Brameld noted: "In simplest terms, education already projects and thereby reinforces whatever habits of personal and cultural life are considered to be acceptable and dominant." The effects of teacher attitudes, beliefs and values, affecting their expectations have been tested repeatedly.
The phenomenon of the "inevitability of war" is a self-fulfilling prophecy that has received considerable study.
The idea is similar to that discussed by the philosopher William James as The Will to Believe. But James viewed it positively, as the self-validation of a belief. Just as, in Merton's example, the belief that a bank is insolvent may help create the fact, so too on the positive side, confidence in the bank's prospects may help brighten them. A more Jamesian example: a swain, convinced that the fair maiden must love him, may prove more effective in his wooing than he would had his initial prophecy been defeatist.
There is extensive evidence of "Interpersonal Expectation Effects" where the seemingly private expectations of individuals can predict the outcome of the world around them. The mechanisms by which this occurs are also reasonably well understood: it is simply that our own expectations change our behaviour in ways we may not notice and correct. In the case of the "Interpersonal Expectation Effects", others pick up on non-verbal behaviour which affects their attitudes. A famous example includes a study where teachers were told arbitrarily that random students were "going to blossom". Oddly, those random students actually ended the year with significantly greater improvements.
Other specific examples discussed in psychology include:'Clever Hans' effect
In Canadian hockey, junior league players are selected based on skill, motor coordination, physical maturity, and other individual merit criteria. However, psychologist Robert Barnsley showed that in any elite group of hockey players, 40% are born between January and March, versus the approximately 25% as would be predicted by statistics. The explanation is that in Canada, the eligibility cutoff for age-class hockey is January 1, and the players who are born in the first months of the year are older by 0–11 months, which at the preadolescent age of selection (nine or ten) manifests into an important physical advantage. The selected players are exposed to higher levels of coaching, play more games, and have better teammates. These factors make them actually become the best players, fulfilling the prophecy, while the real selection criterion was age. The same relative age effect has been noticed in Belgian soccer after 1997, when the start of the selection year was changed from August 1 to January 1.
This specific form of self-fulfilling prophecy is very common and takes many forms. For example, the expectancy for a political party to act in a certain way—based on race, religion, gender and much more—can eventually lead the said party to imitate the stereotype.
In literature, self-fulfilling prophecies are often used as plot devices. They have been used in stories for millennia, but have gained a lot of popularity recently in the science fiction genre. They are typically used ironically, with the prophesied events coming to pass due to the actions of one trying to prevent the prophecy (a recent example would be the life of Anakin Skywalker, the fictional Jedi-turned-Sith Lord in George Lucas' Star Wars saga). They are also sometimes used as comic relief.
Many myths, legends and fairy tales make use of this motif as a central element of narratives that are designed to illustrate inexorable fate, fundamental to the Hellenic world-view. In a common motif, a child, whether newborn or not yet conceived, is prophesied to cause something that those in power do not want to happen. This may be the death of the powerful person; in more light-hearted versions, it is often the marriage of a poor or lower-class child to his own. The events come about, nevertheless, as a result of the actions taken to prevent them: frequently child abandonment sets the chain of events in motion.
The best known example from Greek legend is that of Oedipus. Warned that his child would one day kill him, Laius abandoned his newborn son Oedipus to die, but Oedipus was found and raised by others, and thus in ignorance of his true origins. When he grew up, Oedipus was warned that he would kill his father and marry his mother. Believing his foster parents were his real parents, he left his home and travelled to Greece, eventually reaching the city where his biological parents lived. There, he got into a fight with a stranger, his real father, killed him and married his widow, Oedipus' real mother.
Although the legend of Perseus opens with the prophecy that he will kill his grandfather Acrisius, and his abandonment with his mother Danaë, the prophecy is only self-fulfilling in some variants. In some, he accidentally spears his grandfather at a competition—an act that could have happened regardless of Acrisius' response to the prophecy. In other variants, his presence at the games is explained by his hearing of the prophecy, so that his attempt to evade it does cause the prophecy to be fulfilled. In still others, Acrisius is one of the wedding guests when Polydectes tried to force Danaë to marry him, and when Perseus turns them to stone with the Gorgon's head; as Polydectes fell in love with Danaë because Acrisius abandoned her at sea, and Perseus killed the Gorgon as a consequence of Polydectes' attempt to get rid of Danaë's son so that he could marry her, the prophecy fulfilled itself in these variants.
Greek historiography provides a famous variant: when the Lydian king Croesus asked the Delphic Oracle if he should invade Persia, the response came that if he did, he would destroy a great kingdom. Assuming this meant he would succeed, he attacked—but the kingdom he destroyed was his own. In such an example, the prophecy prompts someone to action because he is led to expect a favorable result; but he achieves another, disastrous result which nonetheless fulfills the prophecy.
People do not necessarily have to unsuccessfully avoid a prophecy in order for the prophecy to be self-fulfilling. For example, when it was predicted that Zeus would overthrow his father, Cronos, and usurp his throne as King of the Gods, he actively waged war against him in a direct attempt to fulfill this prophecy. This makes the prophecy a self-fulfilling one because it was the prophecy itself that gave Zeus the inspiration to do it in the first place.
The story of Romulus and Remus is another example. According to legend, a man overthrew his brother, the king. He then ordered that his two nephews, Romulus and Remus, be drowned, fearing that they would someday kill him like he did to his brother. The boys were placed in a basket and thrown in the Tiber River. A wolf found the babies and she raised them. Later, a shepherd found the twins and named them Romulus and Remus. As teenagers, they found out who they were. They killed their uncle, fulfilling the prophecy.
A variation of the self-fulfilling prophecy is the self-fulfilling dream, which dates back to medieval Arabic literature. Several tales in the One Thousand and One Nights, also known as the Arabian Nights, use this device to foreshadow what is going to happen, as a special form of literary prolepsis. A notable example is "The Ruined Man Who Became Rich Again Through a Dream", in which a man is told in his dream to leave his native city of Baghdad and travel to Cairo, where he will discover the whereabouts of some hidden treasure. The man travels there and experiences misfortune after losing belief in the prophecy, ending up in jail, where he tells his dream to a police officer. The officer mocks the idea of foreboding dreams and tells the protagonist that he himself had a dream about a house with a courtyard and fountain in Baghdad where treasure is buried under the fountain. The man recognizes the place as his own house and, after he is released from jail, he returns home and digs up the treasure. In other words, the foreboding dream not only predicted the future, but the dream was the cause of its prediction coming true. A variant of this story later appears in English folklore as the "Pedlar of Swaffham".
Another variation of the self-fulfilling prophecy can be seen in "The Tale of Attaf", where Harun al-Rashid consults his library (the House of Wisdom), reads a random book, "falls to laughing and weeping and dismisses the faithful vizier" Ja'far ibn Yahya from sight. Ja'far, "disturbed and upset flees Baghdad and plunges into a series of adventures in Damascus, involving Attaf and the woman whom Attaf eventually marries." After returning to Baghdad, Ja'far reads the same book that caused Harun to laugh and weep, and discovers that it describes his own adventures with Attaf. In other words, it was Harun's reading of the book that provoked the adventures described in the book to take place. This is an early example of reverse causality. In the 12th century, this tale was translated into Latin by Petrus Alphonsi and included in his Disciplina Clericalis. In the 14th century, a version of this tale also appears in the Gesta Romanorum and Giovanni Boccaccio's The Decameron.
Self-fulfilling prophecies appear in classical Sanskrit literature. In the story of Krishna in the Indian epic Mahabharata, the ruler of the Mathura kingdom, Kamsa, afraid of a prophecy that predicted his death at the hands of his sister Devaki's son, had her cast into prison where he planned to kill all of her children at birth. After killing the first six children, and Devaki's apparent miscarriage of the seventh, Krishna (the eighth son) was born. As his life was in danger he was smuggled out to be raised by his foster parents Yashoda and Nanda in the village of Gokula. Years later, Kansa learned about the child's escape and kept sending various demons to put an end to him. The demons were defeated at the hands of Krishna and his brother Balarama. Krishna as a young man returned to Mathura to overthrow his uncle, and Kansa was eventually killed by his nephew Krishna. It was due to Kansa's attempts to prevent the prophecy that led to it coming true, thus fulfilling the prophecy.
Oleg of Novgorod was a Varangian prince who ruled of the Rus people during the early tenth century. As old East Slavic chronicles say it was prophesied by the pagan priests that Oleg would take death from his stallion. To avoid this he sent the horse away. Many years later he asked where his horse was, and was told it had died. He asked to see the remains and was taken to the place where the bones lay. When he touched the horse's skull with his boot a snake slithered from the skull and bit him. Oleg died, thus fulfilling the prophecy. In the Primary Chronicle, Oleg is known as the Prophet, ironically referring to the circumstances of his death. The story was romanticized by Alexander Pushkin in his celebrated ballad "The Song of the Wise Oleg". In Scandinavian traditions, this legend lived on in the saga of Orvar-Odd.
Many fairy tales, such as The Devil With the Three Golden Hairs, The Fish and the Ring, The Story of Three Wonderful Beggars, or The King Who Would Be Stronger Than Fate, revolve about a prophecy that a poor boy will marry a rich girl (or, less frequently, a poor girl a rich boy). This is story type 930 in the Aarne–Thompson classification scheme. The girl's father's efforts to prevent it are the reason why the boy ends up marrying her.
Another fairy tale occurs with older children. In The Language of the Birds, a father forces his son to tell him what the birds say: that the father would be the son's servant. In The Ram, the father forces his daughter to tell him her dream: that her father would hold an ewer for her to wash her hands in. In all such tales, the father takes the child's response as evidence of ill-will and drives the child off; this allows the child to change so that the father will not recognize his own offspring later and so offer to act as the child's servant.
In some variants of Sleeping Beauty, such as Sun, Moon, and Talia, the sleep is not brought about by a curse, but a prophecy that she will be endangered by flax (or hemp) results in the royal order to remove all the flax or hemp from the castle, resulting in her ignorance of the danger and her curiosity.
Shakespeare's Macbeth is another classic example of a self-fulfilling prophecy. The three witches give Macbeth a prophecy that Macbeth will eventually become king, but afterwards, the offspring of his best friend will rule instead of his own. Macbeth tries to make the first half true while trying to keep his bloodline on the throne instead of his friend's. Spurred by the prophecy, he kills the king and his friend, something he, arguably, never would have done before. In the end, the evil actions he committed to avoid his succession by another's bloodline get him killed in a revolution.
The later prophecy by the first apparition of the witches that Macbeth should "Beware Macduff" is also a self-fulfilling prophecy. If Macbeth had not been told this, then he might not have regarded Macduff as a threat. Therefore, he would not have killed Macduff's family, and Macduff would not have sought revenge and killed Macbeth.
Similar to Oedipus above, a more modern example would be Darth Vader in the Star Wars films, or Lord Voldemort in the Harry Potter franchise- each attempted to take steps to prevent action against them which had been predicted could cause their downfall, but instead created the conditions leading to it. Another, less well-known, modern example occurred with the character John Mitchell on BBC Three's Being Human. The Disney television series That's So Raven stars Raven-Symoné as the title character with the ability to see into the future with a strange situation. The extreme steps that the character takes to prevent the situation are almost always what lead to it.
The law of attraction is a typical example of self-fulfilling prophecy. It is the name given to the belief that "like attracts like" and that by focusing on positive or negative thoughts, one can bring about positive or negative results. According to this law, all things are created first by imagination, which leads to thoughts, then to words and actions. The thoughts, words and actions held in mind affect someone's intentions which makes the expected result happen. Although there are some cases where positive or negative attitudes can produce corresponding results (principally the placebo and nocebo effects), there is no scientific basis to the law of attraction.
A self-fulfilling prophecy may be a form of causality loop, only when the prophecy can be said to be truly known to occur, since only then events in the future will be causing effects in the past. Otherwise, it would be a simple case of events in the past causing events in the future. Predestination does not necessarily involve a supernatural power, and could be the result of other "infallible foreknowledge" mechanisms. Problems arising from infallibility and influencing the future are explored in Newcomb's paradox. A notable fictional example of a self-fulfilling prophecy occurs in classical play Oedipus Rex, in which Oedipus becomes the king of Thebes, whilst in the process unwittingly fulfills a prophecy that he would kill his father and marry his mother. The prophecy itself serves as the impetus for his actions, and thus it is self-fulfilling. The movie 12 Monkeys heavily deals with themes of predestination and the Cassandra complex, where the protagonist who travels back in time explains that he can't change the past.