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Sunday, July 28, 2024

Alternate history

From Wikipedia, the free encyclopedia
A painting by Jakub Różalski depicts an alternate history of the 1920s, in which rural peasants must contend with giant mechanical walking tanks.

Alternate history (also referred to as alternative history, allohistory, althist, or simply AH) is a subgenre of speculative fiction in which one or more historical events have occurred but are resolved differently than in actual history. As conjecture based upon historical fact, alternate history stories propose What if? scenarios about crucial events in human history, and present outcomes very different from the historical record. Some alternate histories are considered a subgenre of science fiction, or historical fiction.

Since the 1950s, as a subgenre of science fiction, some alternative history stories have featured the tropes of time travel between histories, the psychic awareness of the existence of an alternative universe by the inhabitants of a given universe, and time travel that divides history into various timestreams.

Definition

Often described as a subgenre of science fiction, alternative history is a genre of fiction wherein the author speculates upon how the course of history might have been altered if a particular historical event had an outcome different from the real life outcome. An alternate history requires three conditions: (i) A point of divergence from the historical record, before the time in which the author is writing; (ii) A change that would alter known history; and (iii) An examination of the ramifications of that alteration to history. Occasionally, some types of genre fiction are misidentified as alternative history, specifically science fiction stories set in a time that was the future for the writer, but now is the past for the reader, such as the novels 2001: A Space Odyssey (1968) by Arthur C. Clarke, 1984 (1949) by George Orwell and the movie 2012 (2009) because the authors did not alter the real history of the past when they wrote the stories.

Similar to the genre of alternative history, there is also the genre of secret history - which can be either fictional or non-fictional - which documents events that might have occurred in history, but which had no effect upon the recorded historical outcome. Alternative history also is thematically related to, but distinct from, counterfactual history, which is a form of historiography that explores historical events in an extrapolated timeline in which key historical events either did not occur or had an outcome different from the historical record, in order to understand what did happen.

History of literature

Antiquity and medieval

Title page of the first Spanish-language translation of Joanot Martorell's Tirant lo Blanch (originally in Catalan)

The earliest example of alternate (or counterfactual) history is found in Livy's Ab Urbe Condita Libri (book IX, sections 17–19). Livy contemplated an alternative 4th century BC in which Alexander the Great had survived to attack Europe as he had planned; asking, "What would have been the results for Rome if she had been engaged in a war with Alexander?" Livy concluded that the Romans would likely have defeated Alexander. An even earlier possibility is Herodotus's Histories, which contains speculative material.

Another example of counterfactual history was posited by cardinal and Doctor of the Church Peter Damian in the 11th century. In his famous work De Divina Omnipotentia, a long letter in which he discusses God's omnipotence, he treats questions related to the limits of divine power, including the question of whether God can change the past, for example, bringing about that Rome was never founded:

I see I must respond finally to what many people, on the basis of your holiness's [own] judgment, raise as an objection on the topic of this dispute. For they say: If, as you assert, God is omnipotent in all things, can he manage this, that things that have been made were not made? He can certainly destroy all things that have been made, so that they do not exist now. But it cannot be seen how he can bring it about that things that have been made were not made. To be sure, it can come about that from now on and hereafter Rome does not exist; for it can be destroyed. But no opinion can grasp how it can come about that it was not founded long ago...

One early work of fiction detailing an alternate history is Joanot Martorell's 1490 epic romance Tirant lo Blanch, which was written when the fall of Constantinople to the Turks was still a recent and traumatic memory for Christian Europe. It tells the story of the knight Tirant the White from Brittany who travels to the embattled remnants of the Byzantine Empire. He becomes a Megaduke and commander of its armies and manages to fight off the invading Ottoman armies of Mehmet II. He saves the city from Islamic conquest, and even chases the Turks deeper into lands they had previously conquered.

19th century

One of the earliest works of alternate history published in large quantities for the reception of a large audience may be Louis Geoffroy's Histoire de la Monarchie universelle : Napoléon et la conquête du monde (1812–1832) (History of the Universal Monarchy: Napoleon and the Conquest of the World) (1836), which imagines Napoleon's First French Empire emerging victorious in the French invasion of Russia in 1812 and in an invasion of England in 1814, later unifying the world under Bonaparte's rule.

The Book of Mormon (published 1830) is described as an "alternative history" by Richard Lyman Bushman, a biographer of Joseph Smith. Smith claimed to have translated the document from golden plates, which told the story of a Jewish group who migrated from Israel to the Americas and inhabited the region from about 600 B.C. to 400 A.D., becoming the ancestors of Native Americans. In the 2005 biography Joseph Smith: Rough Stone Rolling, Bushman wrote that the Book of Mormon "turned American history upside down [and] works on the premise that a history—a book—can reconstitute a nation. It assumes that by giving a nation an alternative history, alternative values can be made to grow."

In the English language, the first known complete alternate history may be Nathaniel Hawthorne's short story "P.'s Correspondence", published in 1845. It recounts the tale of a man who is considered "a madman" due to his perceptions of a different 1845, a reality in which long-dead famous people, such as the poets Robert Burns, Lord Byron, Percy Bysshe Shelley and John Keats, the actor Edmund Kean, the British politician George Canning, and Napoleon Bonaparte, are still alive.

The first novel-length alternate history in English would seem to be Castello Holford's Aristopia (1895). While not as nationalistic as Louis Geoffroy's Napoléon et la conquête du monde, 1812–1823, Aristopia is another attempt to portray a Utopian society. In Aristopia, the earliest settlers in Virginia discover a reef made of solid gold and are able to build a Utopian society in North America.

Early 20th century and the era of the pulps

In 1905, H. G. Wells published A Modern Utopia. As explicitly noted in the book itself, Wells's main aim in writing it was to set out his social and political ideas, the plot serving mainly as a vehicle to expound them. This book introduced the idea of a person being transported from a point in our familiar world to the precise geographical equivalent point in an alternate world in which history had gone differently. The protagonists undergo various adventures in the alternate world, and then are finally transported back to our world, again to the precise geographical equivalent point. Since then, that has become a staple of the alternate history genre.

A number of alternate history stories and novels appeared in the late 19th and early 20th centuries (see, for example, Joseph Edgar Chamberlin's The Ifs of History [1907] and Charles Petrie's If: A Jacobite Fantasy [1926]). In 1931, British historian Sir John Squire collected a series of essays from some of the leading historians of the period for his anthology If It Had Happened Otherwise. In that work, scholars from major universities, as well as important non-academic authors, turned their attention to such questions as "If the Moors in Spain Had Won" and "If Louis XVI Had Had an Atom of Firmness". The essays range from serious scholarly efforts to Hendrik Willem van Loon's fanciful and satiric portrayal of an independent 20th-century New Amsterdam, a Dutch city-state on the island of Manhattan. Among the authors included were Hilaire Belloc, André Maurois, and Winston Churchill.

One of the entries in Squire's volume was Churchill's "If Lee Had Not Won the Battle of Gettysburg", written from the viewpoint of a historian in a world in which the Confederacy had won the American Civil War. The entry considers what would have happened if the North had been victorious (in other words, a character from an alternate world imagines a world more like the real one we live in, although it is not identical in every detail). Speculative work that narrates from the point of view of an alternate history is variously known as "recursive alternate history", a "double-blind what-if", or an "alternate-alternate history". Churchill's essay was one of the influences behind Ward Moore's alternate history novel Bring the Jubilee in which General Robert E. Lee won the Battle of Gettysburg and paved the way for the eventual victory of the Confederacy in the American Civil War (named the "War of Southron Independence" in this timeline). The protagonist, the autodidact Hodgins Backmaker, travels back to the aforementioned battle and inadvertently changes history, which results in the emergence of our own timeline and the consequent victory of the Union instead.

The American humorist author James Thurber parodied alternate history stories about the American Civil War in his 1930 story "If Grant Had Been Drinking at Appomattox", which he accompanied with this very brief introduction: "Scribner's magazine is publishing a series of three articles: 'If Booth Had Missed Lincoln', 'If Lee Had Won the Battle of Gettysburg', and 'If Napoleon Had Escaped to America'. This is the fourth".

Another example of alternate history from this period (and arguably the first that explicitly posited cross-time travel from one universe to another as anything more than a visionary experience) is H.G. Wells' Men Like Gods (1923) in which the London-based journalist Mr. Barnstable, along with two cars and their passengers, is mysteriously teleported into "another world", which the "Earthlings" call Utopia. Being far more advanced than Earth, Utopia is some 3000 years ahead of humanity in its development. Wells describes a multiverse of alternative worlds, complete with the paratime travel machines that would later become popular with American pulp writers. However, since his hero experiences only a single alternate world, the story is not very different from conventional alternate history.

In the 1930s, alternate history moved into a new arena. The December 1933 issue of Astounding published Nat Schachner's "Ancestral Voices", which was quickly followed by Murray Leinster's "Sidewise in Time" (1934). While earlier alternate histories examined reasonably-straightforward divergences, Leinster attempted something completely different. In his "World gone mad", pieces of Earth traded places with their analogs from different timelines. The story follows Professor Minott and his students from a fictitious Robinson College as they wander through analogues of worlds that followed a different history. "Sidewise in Time" has been described as "the point at which the alternate history narrative first enters science fiction as a plot device" and is the story for which the Sidewise Award for Alternate History is named.

The world in 1964 in the novel Fatherland in which the Nazis won World War II

A somewhat similar approach was taken by Robert A. Heinlein in his 1941 novelette Elsewhen in which a professor trains his mind to move his body across timelines. He then hypnotizes his students so that they can explore more of them. Eventually, each settles into the reality that is most suitable for him or her. Some of the worlds they visit are mundane, some are very odd, and others follow science fiction or fantasy conventions.

World War II produced alternate history for propaganda: both British and American authors wrote works depicting Nazi invasions of their respective countries as cautionary tales.

Time travel to create historical divergences

The period around World War II also saw the publication of the time travel novel Lest Darkness Fall by L. Sprague de Camp in which an American academic travels to Italy at the time of the Byzantine invasion of the Ostrogoths. De Camp's time traveler, Martin Padway, is depicted as making permanent historical changes and implicitly forming a new time branch, thereby making the work an alternate history.

In William Tenn's short story Brooklyn Project (1948), a tyrannical US Government brushes aside the warnings of scientists about the dangers of time travel and goes on with a planned experiment - with the result that minor changes to the prehistoric past cause Humanity to never have existed, its place taken by tentacled underwater intelligent creatures - who also have a tyrannical government which also insists on experimenting with time-travel.

Time travel as the cause of a point of divergence (POD), which can denote either the bifurcation of a historical timeline or a simple replacement of the future that existed before the time-travelling event, has continued to be a popular theme. In Ward Moore's Bring the Jubilee (1953), the protagonist lives in an alternate history in which the Confederacy has won the American Civil War. He travels backward through time and brings about a Union victory at the Battle of Gettysburg.

When a story's assumptions about the nature of time travel lead to the complete replacement of the visited time's future, rather than just the creation of an additional time line, the device of a "time patrol" is often used where guardians move through time to preserve the "correct" history.

A more recent example is Making History by Stephen Fry in which a time machine is used to alter history so that Adolf Hitler was never born. That ironically results in a more competent leader of Nazi Germany and results in the country's ascendancy and longevity in the altered timeline.

Quantum theory of many worlds

While many justifications for alternate histories involve a multiverse, the "many world" theory would naturally involve many worlds, in fact a continually exploding array of universes. In quantum theory, new worlds would proliferate with every quantum event, and even if the writer uses human decisions, every decision that could be made differently would result in a different timeline. A writer's fictional multiverse may, in fact, preclude some decisions as humanly impossible, as when, in Night Watch, Terry Pratchett depicts a character informing Vimes that while anything that can happen, has happened, nevertheless there is no history whatsoever in which Vimes has ever murdered his wife. When the writer explicitly maintains that all possible decisions are made in all possible ways, one possible conclusion is that the characters were neither brave, nor clever, nor skilled, but simply lucky enough to happen on the universe in which they did not choose the cowardly route, take the stupid action, fumble the crucial activity, etc.; few writers focus on this idea, although it has been explored in stories such as Larry Niven's story All the Myriad Ways, where the reality of all possible universes leads to an epidemic of suicide and crime because people conclude their choices have no moral import.

In any case, even if it is true that every possible outcome occurs in some world, it can still be argued that traits such as bravery and intelligence might still affect the relative frequency of worlds in which better or worse outcomes occurred (even if the total number of worlds with each type of outcome is infinite, it is still possible to assign a different measure to different infinite sets). The physicist David Deutsch, a strong advocate of the many-worlds interpretation of quantum mechanics, has argued along these lines, saying that "By making good choices, doing the right thing, we thicken the stack of universes in which versions of us live reasonable lives. When you succeed, all the copies of you who made the same decision succeed too. What you do for the better increases the portion of the multiverse where good things happen." This view is perhaps somewhat too abstract to be explored directly in science fiction stories, but a few writers have tried, such as Greg Egan in his short story The Infinite Assassin, where an agent is trying to contain reality-scrambling "whirlpools" that form around users of a certain drug, and the agent is constantly trying to maximize the consistency of behavior among his alternate selves, attempting to compensate for events and thoughts he experiences, he guesses are of low measure relative to those experienced by most of his other selves.

Many writers—perhaps the majority—avoid the discussion entirely. In one novel of this type, H. Beam Piper's Lord Kalvan of Otherwhen, a Pennsylvania State Police officer, who knows how to make gunpowder, is transported from our world to an alternate universe where the recipe for gunpowder is a tightly held secret and saves a country that is about to be conquered by its neighbors. The paratime patrol members are warned against going into the timelines immediately surrounding it, where the country will be overrun, but the book never depicts the slaughter of the innocent thus entailed, remaining solely in the timeline where the country is saved.

The cross-time theme was further developed in the 1960s by Keith Laumer in the first three volumes of his Imperium sequence, which would be completed in Zone Yellow (1990). Piper's politically more sophisticated variant was adopted and adapted by Michael Kurland and Jack Chalker in the 1980s; Chalker's G.O.D. Inc trilogy (1987–89), featuring paratime detectives Sam and Brandy Horowitz, marks the first attempt at merging the paratime thriller with the police procedural. Kurland's Perchance (1988), the first volume of the never-completed "Chronicles of Elsewhen", presents a multiverse of secretive cross-time societies that utilize a variety of means for cross-time travel, ranging from high-tech capsules to mutant powers. Harry Turtledove has launched the Crosstime Traffic series for teenagers featuring a variant of H. Beam Piper's paratime trading empire.

Rival paratime worlds

The concept of a cross-time version of a world war, involving rival paratime empires, was developed in Fritz Leiber's Change War series, starting with the Hugo Award winning The Big Time (1958); followed by Richard C. Meredith's Timeliner trilogy in the 1970s, Michael McCollum's A Greater Infinity (1982) and John Barnes' Timeline Wars trilogy in the 1990s.

Such "paratime" stories may include speculation that the laws of nature can vary from one universe to the next, providing a science fictional explanation—or veneer—for what is normally fantasy. Aaron Allston's Doc Sidhe and Sidhe Devil take place between our world, the "grim world" and an alternate "fair world" where the Sidhe retreated to. Although technology is clearly present in both worlds, and the "fair world" parallels our history, about fifty years out of step, there is functional magic in the fair world. Even with such explanation, the more explicitly the alternate world resembles a normal fantasy world, the more likely the story is to be labelled fantasy, as in Poul Anderson's "House Rule" and "Loser's Night". In both science fiction and fantasy, whether a given parallel universe is an alternate history may not be clear. The writer might allude to a POD only to explain the existence and make no use of the concept, or may present the universe without explanation of its existence.

Major writers explore alternate histories

Isaac Asimov's short story "What If—" (1952) is about a couple who can explore alternate realities by means of a television-like device. This idea can also be found in Asimov's novel The End of Eternity (1955), in which the "Eternals" can change the realities of the world, without people being aware of it. Poul Anderson's Time Patrol stories feature conflicts between forces intent on changing history and the Patrol who work to preserve it. One story, Delenda Est, describes a world in which Carthage triumphed over the Roman Republic. The Big Time, by Fritz Leiber, describes a Change War ranging across all of history.

Keith Laumer's Worlds of the Imperium is one of the earliest alternate history novels; it was published by Fantastic Stories of the Imagination in 1961, in magazine form, and reprinted by Ace Books in 1962 as one half of an Ace Double. Besides our world, Laumer describes a world ruled by an Imperial aristocracy formed by the merger of European empires, in which the American Revolution never happened, and a third world in post-war chaos ruled by the protagonist's doppelganger.

A map of the United States as depicted in The Man in the High Castle TV series, based on Philip K. Dick's The Man in the High Castle

Philip K. Dick's novel, The Man in the High Castle (1962), is an alternate history in which Nazi Germany and Imperial Japan won World War II. This book contains an example of "alternate-alternate" history, in that one of its characters authored a book depicting a reality in which the Allies won the war, itself divergent from real-world history in several aspects. The several characters live within a divided United States, in which the Empire of Japan takes the Pacific states, governing them as a puppet, Nazi Germany takes the East Coast of the United States and parts of the Midwest, with the remnants of the old United States' government as the Neutral Zone, a buffer state between the two superpowers. The book has inspired an Amazon series of the same name.

Vladimir Nabokov's novel, Ada or Ardor: A Family Chronicle (1969), is a story of incest that takes place within an alternate North America settled in part by Czarist Russia and that borrows from Dick's idea of "alternate-alternate" history (the world of Nabokov's hero is wracked by rumors of a "counter-earth" that apparently is ours). Some critics believe that the references to a counter-earth suggest that the world portrayed in Ada is a delusion in the mind of the hero (another favorite theme of Dick's novels). Strikingly, the characters in Ada seem to acknowledge their own world as the copy or negative version, calling it "Anti-Terra", while its mythical twin is the real "Terra". Like history, science has followed a divergent path on Anti-Terra: it boasts all the same technology as our world, but all based on water instead of electricity; e.g., when a character in Ada makes a long-distance call, all the toilets in the house flush at once to provide hydraulic power.

Guido Morselli described the defeat of Italy (and subsequently France) in World War I in his novel, Past Conditional (1975; Contro-passato prossimo), wherein the static Alpine front line which divided Italy from Austria during that war collapses when the Germans and the Austrians forsake trench warfare and adopt blitzkrieg twenty years in advance.

Kingsley Amis set his novel, The Alteration (1976), in the 20th century, but major events in the Reformation did not take place, and Protestantism is limited to the breakaway Republic of New England. Martin Luther was reconciled to the Roman Catholic Church and later became Pope Germanian I.

In Nick Hancock and Chris England's 1997 book What Didn't Happen Next: An Alternative History of Football it is suggested that, had Gordon Banks been fit to play in the 1970 FIFA World Cup quarter-final, there would have been no Thatcherism and the post-war consensus would have continued indefinitely.

Kim Stanley Robinson's novel, The Years of Rice and Salt (2002), starts at the point of divergence with Timur turning his army away from Europe, and the Black Death has killed 99% of Europe's population, instead of only a third. Robinson explores world history from that point in AD 1405 (807 AH) to about AD 2045 (1467 AH). Rather than following the great man theory of history, focusing on leaders, wars, and major events, Robinson writes more about social history, similar to the Annales School of history theory and Marxist historiography, focusing on the lives of ordinary people living in their time and place.

Philip Roth's novel, The Plot Against America (2004), looks at an America where Franklin D. Roosevelt is defeated in 1940 in his bid for a third term as President of the United States, and Charles Lindbergh is elected, leading to a US that features increasing fascism and anti-Semitism.

Michael Chabon, occasionally an author of speculative fiction, contributed to the genre with his novel The Yiddish Policemen's Union (2007), which explores a world in which the State of Israel was destroyed in its infancy and many of the world's Jews instead live in a small strip of Alaska set aside by the US government for Jewish settlement. The story follows a Jewish detective solving a murder case in the Yiddish-speaking semi-autonomous city state of Sitka. Stylistically, Chabon borrows heavily from the noir and detective fiction genres, while exploring social issues related to Jewish history and culture. Apart from the alternate history of the Jews and Israel, Chabon also plays with other common tropes of alternate history fiction; in the book, Germany actually loses the war even harder than they did in reality, getting hit with a nuclear bomb instead of just simply losing a ground war (subverting the common "what if Germany won WWII?" trope).

The world of 1942, as depicted at the start of S. M. Stirling's The Domination series
World War I from Harry Turtledove's Southern Victory ("Timeline 191") series

The late 1980s and the 1990s saw a boom in popular-fiction versions of alternate history, fueled by the emergence of the prolific alternate history author Harry Turtledove, as well as the development of the steampunk genre and two series of anthologies—the What Might Have Been series edited by Gregory Benford and the Alternate ... series edited by Mike Resnick. This period also saw alternate history works by S. M. Stirling, Kim Stanley Robinson, Harry Harrison, Howard Waldrop, Peter Tieryas, and others.

In 1986, a sixteen-part epic comic book series called Captain Confederacy began examining a world where the Confederate States of America won the American Civil War. In the series, the Captain and others heroes are staged government propaganda events featuring the feats of these superheroes.

Since the late 1990s, Harry Turtledove has been the most prolific practitioner of alternate history and has been given the title "Master of Alternate History" by some. His books include those of Timeline 191 (a.k.a. Southern Victory, also known as TL-191), in which, while the Confederate States of America won the American Civil War, the Union and Imperial Germany defeat the Entente Powers in the two "Great War"s of the 1910s and 1940s (with a Nazi-esque Confederate government attempting to exterminate its Black population), and the Worldwar series, in which aliens invaded Earth during World War II. Other stories by Turtledove include A Different Flesh, in which America was not colonized from Asia during the last ice age; In the Presence of Mine Enemies, in which the Nazis won World War II; and Ruled Britannia, in which the Spanish Armada succeeded in conquering England in the Elizabethan era, with William Shakespeare being given the task of writing the play that will motivate the Britons to rise up against their Spanish conquerors. He also co-authored a book with actor Richard Dreyfuss, The Two Georges, in which the United Kingdom retained the American colonies, with George Washington and King George III making peace. He did a two-volume series in which the Japanese not only bombed Pearl Harbor but also invaded and occupied the Hawaiian Islands.

Perhaps the most incessantly explored theme in popular alternate history focuses on worlds in which the Nazis won World War Two. In some versions, the Nazis and/or Axis Powers win; or in others, they conquer most of the world but a "Fortress America" exists under siege; while in others, there is a Nazi/Japanese Cold War comparable to the US/Soviet equivalent in 'our' timeline. Fatherland (1992), by Robert Harris, is set in Europe following the Nazi victory. The novel Dominion by C.J. Sansom (2012) is similar in concept but is set in England, with Churchill the leader of an anti-German Resistance and other historic persons in various fictional roles. In the Mecha Samurai Empire series (2016), Peter Tieryas focuses on the Asian-American side of the alternate history, exploring an America ruled by the Japanese Empire while integrating elements of Asian pop culture like mechas and videogames.

Several writers have posited points of departure for such a world but then have injected time splitters from the future. For instance James P. Hogan's The Proteus Operation. Norman Spinrad wrote The Iron Dream in 1972, which is intended to be a science fiction novel written by Adolf Hitler after fleeing from Europe to North America in the 1920s.

In Jo Walton's "Small Change" series, the United Kingdom made peace with Hitler before the involvement of the United States in World War II, and slowly collapses due to severe economic depression. Former House Speaker Newt Gingrich and William R. Forstchen have written a novel, 1945, in which the US defeated Japan but not Germany in World War II, resulting in a Cold War with Germany rather than the Soviet Union. Gingrich and Forstchen neglected to write the promised sequel; instead, they wrote a trilogy about the American Civil War, starting with Gettysburg: A Novel of the Civil War, in which the Confederates win a victory at the Battle of Gettysburg - however, after Lincoln responds by bringing Grant and his forces to the eastern theater, the Army of Northern Virginia is soon trapped and destroyed in Maryland, and the war ends within weeks.

While World War II has been a common Point of Divergence in alternate history literature, several works have been based on other points of divergence. For example, Martin Cruz Smith, in his first novel, posited an independent American Indian nation following the defeat of Custer in The Indians Won (1970). Beginning with The Probability Broach in 1980, L. Neil Smith wrote several novels that postulated the disintegration of the US Federal Government after Albert Gallatin joins the Whiskey Rebellion in 1794 and eventually leads to the creation of a libertarian utopia. In the 2022 novel Poutine and Gin by Steve Rhinelander, the point of divergence is the Battle of the Plains of Abraham of the French and Indian War. That novel is a mystery set in 1940 of that time line.

A recent time traveling splitter variant involves entire communities being shifted elsewhere to become the unwitting creators of new time branches. These communities are transported from the present (or the near-future) to the past or to another timeline via a natural disaster, the action of technologically advanced aliens, or a human experiment gone wrong. S. M. Stirling wrote the Island in the Sea of Time trilogy, in which Nantucket Island and all its modern inhabitants are transported to Bronze Age times to become the world's first superpower. In Eric Flint's 1632 series, a small town in West Virginia is transported to 17th century central Europe and drastically changes the course of the Thirty Years' War, which was then underway. John Birmingham's Axis of Time trilogy deals with the culture shock when a United Nations naval task force from 2021 finds itself back in 1942 helping the Allies against the Empire of Japan and the Germans (and doing almost as much harm as good in spite of its advanced weapons). The series also explores the cultural impacts of people with 2021 ideals interacting with 1940s culture. Similarly, Robert Charles Wilson's Mysterium depicts a failed US government experiment which transports a small American town into an alternative version of the US run by believers in a form of Christianity known as Gnosticism, who are engaged in a bitter war with the "Spanish" in Mexico (the chief scientist at the laboratory where the experiment occurred is described as a Gnostic, and references to Christian Gnosticism appear repeatedly in the book).

Although not dealing in physical time travel, in his alt-history novel Marx Returns, Jason Barker introduces anachronisms into the life and times of Karl Marx, such as when his wife Jenny sings a verse from the Sex Pistols's song "Anarchy in the U.K.", or in the games of chess she plays with the Marxes' housekeeper Helene Demuth, which on one occasion involves a Caro–Kann Defence. In her review of the novel, Nina Power writes of "Jenny's 'utopian' desire for an end to time", an attitude which, according to Power, is inspired by her husband's co-authored book The German Ideology. However, in keeping with the novel's anachronisms, the latter was not published until 1932. By contrast, the novel's timeline ends in 1871.

In the 2022 novel Hydrogen Wars: Atomic Sunrise by R.M. Christianson a small change in post-war Japanese history leads to the election of General Douglas MacArthur as President of the United States. This minor change ultimately leads to all-out atomic war between the major Cold War powers.

Through crowdfunding on Kickstarter, Alan Jenkins and Gan Golan produced a graphic novel series called 1/6 depicting a dystopian alternate reality in which the January 6 United States Capitol attack was successful. What follows is the burning down of the Capitol building and the hanging of Vice President Mike Pence. Under Donald Trump's second term as president, a solid gold statue of him is erected and armed thugs patrol the streets of Washington DC suppressing civilian resistance with brutal violence under the banner of the Confederate flag.

In fantasy genre

The Angevin Empire in 1172, before the point of divergence of Randall Garrett's Lord Darcy series

Many works of straight fantasy and science fantasy take place in historical settings, though with the addition of, for example, magic or mythological beasts. Some present a secret history in which the modern day world no longer believes that these elements ever existed. Many ambiguous alternate/secret histories are set in Renaissance or pre-Renaissance times, and may explicitly include a "retreat" from the world, which would explain the current absence of such phenomena. Other stories make plan a divergence of some kind.

In Poul Anderson's Three Hearts and Three Lions in which the Matter of France is history and the fairy folk are real and powerful. The same author's A Midsummer Tempest occurs in a world in which the plays of William Shakespeare (called here "the Great Historian"), presented the literal truth in every instance. The novel itself takes place in the era of Oliver Cromwell and Charles I. Here, the English Civil War had a different outcome, and the Industrial Revolution has occurred early.

Randall Garrett's "Lord Darcy" series presents a point of divergence: a monk systemizes magic rather than science, so the use of foxglove to treat heart disease is regarded as superstition. Another point of divergence occurs in 1199, when Richard the Lionheart survives the Siege of Chaluz and returns to England and makes the Angevin Empire so strong that it survives into the 20th century.

Jonathan Strange & Mr Norrell by Susanna Clarke takes place in an England where a separate Kingdom ruled by the Raven King and founded on magic existed in Northumbria for over 300 years. In Patricia Wrede's Regency fantasies, Great Britain has a Royal Society of Wizards.

The Tales of Alvin Maker series by Orson Scott Card (a parallel to the life of Joseph Smith, founder of the Latter Day Saint movement) takes place in an alternate America, beginning in the early 19th century. Prior to that time, a POD occurred: England, under the rule of Oliver Cromwell, had banished "makers", or anyone else demonstrating "knacks" (an ability to perform seemingly supernatural feats) to the North American continent. Thus the early American colonists embraced as perfectly ordinary these gifts, and counted on them as a part of their daily lives. The political division of the continent is considerably altered, with two large English colonies bookending a smaller "American" nation, one aligned with England, and the other governed by exiled Cavaliers. Actual historical figures are seen in a much different light: Ben Franklin is revered as the continent's finest "maker", George Washington was executed after being captured, and "Tom" Jefferson is the first president of "Appalachia", the result of a compromise between the Continentals and the British Crown.

On the other hand, when the "Old Ones" (fairies) still manifest themselves in England in Keith Roberts's Pavane, which takes place in a technologically backward world after a Spanish assassination of Elizabeth I allowed the Spanish Armada to conquer England, the possibility that the fairies were real but retreated from modern advances makes the POD possible: the fairies really were present all along, in a secret history.

Again, in the English Renaissance fantasy Armor of Light by Melissa Scott and Lisa A. Barnett, the magic used in the book, by Dr. John Dee and others, actually was practiced in the Renaissance; positing a secret history of effective magic makes this an alternate history with a point of departure. Sir Philip Sidney survives the Battle of Zutphen in 1586, and shortly thereafter saving the life of Christopher Marlowe.

When the magical version of our world's history is set in contemporary times, the distinction becomes clear between alternate history on the one hand and contemporary fantasy, using in effect a form of secret history (as when Josepha Sherman's Son of Darkness has an elf living in New York City, in disguise) on the other. In works such as Robert A. Heinlein's Magic, Incorporated where a construction company can use magic to rig up stands at a sporting event and Poul Anderson's Operation Chaos and its sequel Operation Luna, where djinns are serious weapons of war—with atomic bombs—the use of magic throughout the United States and other modern countries makes it clear that this is not secret history—although references in Operation Chaos to degaussing the effects of cold iron make it possible that it is the result of a POD. The sequel clarifies this as the result of a collaboration of Einstein and Planck in 1901, resulting in the theory of "rhea tics". Henry Moseley applies this theory to "degauss the effects of cold iron and release the goetic forces." This results in the suppression of ferromagnetism and the re-emergence of magic and magical creatures.

Alternate history shades off into other fantasy subgenres when the use of actual, though altered, history and geography decreases, although a culture may still be clearly the original source; Barry Hughart's Bridge of Birds and its sequels take place in a fantasy world, albeit one clearly based on China, and with allusions to actual Chinese history, such as the Empress Wu. Richard Garfinkle's Celestial Matters incorporates ancient Chinese physics and Greek Aristotelian physics, using them as if factual.

Alternate history has long been a staple of Japanese speculative fiction with such authors as Futaro Yamada and Ryō Hanmura writing novels set in recognizable historical settings with added supernatural or science fiction elements. Ryō Hanmura's 1973 Musubi no Yama Hiroku which recreated 400 years of Japan's history from the perspective of a secret magical family with psychic abilities. The novel has since come to be recognized as a masterpiece of Japanese speculative fiction. Twelve years later, author Hiroshi Aramata wrote the groundbreaking Teito Monogatari which reimagined the history of Tokyo across the 20th century in a world heavily influenced by the supernatural.

Television

1983 is set on a world where the Iron Curtain never fell and the Cold War continues until the present (2003).

An Englishman's Castle tells the story of the writer of a soap opera in a 1970s England which lost World War II. England is run by a collaborator government which strains to maintain a normal appearance of British life. Slowly, however, the writer begins to uncover the truth.

In the Community episode "Remedial Chaos Theory," each of the six members of the study group rolls a die to decide who has to go downstairs to accept a pizza delivery for the group, creating 6 different alternative worlds. Characters from the worst universe, "darkest timeline," would later appear in the "prime universe".

Confederate was a planned HBO series set on a world where the south won the US Civil War. Social media backlash during pre-production led to the series being cancelled with no episodes produced.

Counterpart tells of a United Nations agency that is responsible for monitoring passage between alternative worlds. Two of the worlds, Alpha and Prime are locked in a cold war.

The Court-Martial of George Armstrong Custer is a 1977 telemovie where George Custer survives the Battle of Little Bighorn and faces a court martial hearing over his incompetence.

C.S.A.: The Confederate States of America presents itself as a British TV documentary uncovering some of the dark secrets of the Confederacy on a world where the south won the US Civil War.

Dark Skies tells that much of history having been shaped since the 1940s by a government conspiracy with aliens. One race of aliens can take over humans, while those immune to the alien's control fight back.

Doctor Who's main character has visited two alternative worlds in the TV show and several in its spin off media. The Third Doctor visits a world with a fascist Great Britain on the brink of destruction, Inferno while the Tenth Doctor visits a Britain that has a President and blimps are a common form of transportation beset by Cybermen, "Doomsday". The Seventh Doctor faces a threat from an alternative world in Battlefield, where magic is real and the alternative version of The Doctor is hinted to be that reality's Merlin.

Fallout shows a 1950s retro-future world that suffers a global nuclear war  on the Amazon streaming service.

Fatherland is a TV movie set in a 1960 alternative world where US President Joseph Kennedy and Adolf Hitler have agreed to meet to discuss an end to their country's Cold War 15 years after the Axis victory in World War II. However, an American reporter has discovered proof of the long denied Final Solution threatens the meeting.

The anime Fena: Pirate Princess featured an alternate 18th century.

For All Mankind depicts an alternate timeline in which the Soviet crewed lunar program successfully lands on the Moon before the US Apollo program, resulting in a continued and intensified Space Race.

Fringe has the father of one of the main characters cross into another reality to steal that world's version of his son after his son dies. The second world has a slightly different history, with a few different states in the United States, such as only one Carolina and Upper Michigan as a state. In addition, the 9/11 attack didn't take down the Twin Towers but the White House. Also, several major DC Comics events are different, such as Superman not Supergirl dying during Crisis on Infinite Earths. The incursion to steal the son has many negative effects on that world, and while the realities start out as antagonist, they eventually work together to repair the damage.

The Man in the High Castle, an adaptation of the novel of the same name, showed a world where the Axis Powers won World War II.

Motherland: Fort Salem explores a female-dominated world in which witchcraft is real. Its world diverged from our timeline when the Salem witch trials are resolved by an agreement between witches and ungifted humans.

Noughts + Crosses is a British TV show set on a world where a powerful West African empire colonizes Europe 700 years before the start of the series.

Parallels was a planned TV show whose pilot was later released as a Netflix movie. The plot concerns a building which can shift realities every 36 hours and those who use the building to travel to other realities.

The Plot Against America is an HBO miniseries where Charles Lindbergh wins the 1940 US presidential election as an anti-war candidate who moves the country toward fascism.

The TV show Sliders explores different possible alternate realities by having the protagonist "slide" into different parallel dimensions of the same planet Earth.

The Great Martian War 1914-1917 An alternate history documentary where giant martians with machines invaded the Earth during WW1, causing huge technological upgrades and the entente and central powers fighting alongside each other.

SS-GB (TV series) shows a world where the Axis Powers quickly win World War II, killing Churchill and installing a puppet government. However, British resistance fights back.[54]

In the various Star Trek TV shows and spin off media a Mirror Universe has been encountered where Earth has an empire that subjugates other planets. Doppelgängers of the main cast of many the TV shows appear in that reality.

The Watchmen series is set on a world where costumed heroes were initially welcomed but later outlawed. It is set 34 years after the events of the comic book on which the series shares a name.

The Marvel Cinematic Universe series, Loki (2021 & 2023), on Disney+, shows an agency which prevents alterations to the timeline. Alternate versions of Loki from various universes appear.

The Marvel Cinematic Universe series, What If...? (2021-present), on Disney+, shows alternate universes that depict alternate events from the MCU films.

Online

Fans of alternate history have made use of the internet from a very early point to showcase their own works and provide useful tools for those fans searching for anything alternate history, first in mailing lists and usenet groups, later in web databases and forums. The "Usenet Alternate History List" was first posted on 11 April 1991, to the Usenet newsgroup rec.arts.sf-lovers. In May 1995, the dedicated newsgroup soc.history.what-if was created for showcasing and discussing alternate histories. Its prominence declined with the general migration from unmoderated usenet to moderated web forums, most prominently AlternateHistory.com, the self-described "largest gathering of alternate history fans on the internet" with over 10,000 active members.

In addition to these discussion forums, in 1997 Uchronia: The Alternate History List was created as an online repository, now containing over 2,900 alternate history novels, stories, essays, and other printed materials in several different languages. Uchronia was selected as the Sci Fi Channel's "Sci Fi Site of the Week" twice.

Uchronia

In Spanish, French, German, Portuguese, Italian, Catalan, and Galician, the words uchronie, ucronia, and ucronía are native versions of alternate history, from which comes the English loanword uchronia. The English term uchronia is a neologism that is sometimes used in its original meaning as a straightforward synonym for alternate history. However, it may also now refer to other concepts, namely an umbrella genre of fiction that encompasses alternate history, parallel universes in fiction, and fiction based in futuristic or non-temporal settings.

Theory of mind

From Wikipedia, the free encyclopedia

It has been proposed that deficits in theory of mind can occur in people with autism, anorexia nervosa, schizophrenia, dysphoria, cocaine addiction, and brain damage caused by alcohol's neurotoxicity.There is no current consensus on a theory of mind deficit in people with attention deficit hyperactivity disorder (ADHD). Several studies have been carried out and most of them even show the opposite (5/6). It would appear that people with ADHD do not have a theory of mind deficit like autistic people, but that they share other problems with empathy and emotional recognition and/or processing. Neuroimaging shows that the medial prefrontal cortex (mPFC), the posterior superior temporal sulcus (pSTS), the precuneus, and the amygdala are associated with theory of mind tasks. Patients with frontal lobe or temporoparietal junction lesions find some theory of mind tasks difficult. One's theory of mind develops in childhood as the prefrontal cortex develops. It has been argued that children in a culture of collectivism develop knowledge access earlier and understand diverse beliefs later than Western children in a culture of individualism.

Definition

The "theory of mind" is described as a theory, because the behavior of the other person, such as their statements and expressions, is the only thing being directly observed; no one has direct access to the mind of another, and the existence and nature of the mind must be inferred. It is typically assumed others have minds analogous to one's own; this assumption is based on three reciprocal social interactions, as observed in joint attention, the functional use of language, and the understanding of others' emotions and actions. Theory of mind allows one to attribute thoughts, desires, and intentions to others, to predict or explain their actions, and to posit their intentions. It enables one to understand that mental states can be the cause of—and can be used to explain and predict—the behavior of others. Being able to attribute mental states to others and understanding them as causes of behavior implies, in part, one must be able to conceive of the mind as a "generator of representations". If a person does not have a mature theory of mind, it may be a sign of cognitive or developmental impairment.

Theory of mind appears to be an innate potential ability in humans that requires social and other experience over many years for its full development. Different people may develop more or less effective theories of mind. Neo-Piagetian theories of cognitive development maintain that theory of mind is a byproduct of a broader hypercognitive ability of the human mind to register, monitor, and represent its own functioning.

Empathy—the recognition and understanding of the states of mind of others, including their beliefs, desires, and particularly emotions—is a related concept. Empathy is often characterized as the ability to "put oneself into another's shoes". Recent neuro-ethological studies of animal behavior suggest that rodents may exhibit empathetic abilities. While empathy is known as emotional perspective-taking, theory of mind is defined as cognitive perspective-taking.

Research on theory of mind, in humans and animals, adults and children, normally and atypically developing, has grown rapidly in the years since Premack and Guy Woodruff's 1978 paper, "Does the chimpanzee have a theory of mind?". The field of social neuroscience has also begun to address this debate by imaging the brains of humans while they perform tasks that require the understanding of an intention, belief, or other mental state in others.

An alternative account of theory of mind is given in operant psychology and provides empirical evidence for a functional account of both perspective-taking and empathy. The most developed operant approach is founded on research on derived relational responding and is subsumed within relational frame theory. Derived relational responding relies on the ability to identify derived relations, or relationships between stimuli that are not directly learned or reinforced; for example, if "snake" is related to "danger" and "danger" is related to "fear", people may know to fear snakes even without learning an explicit connection between snakes and fear. According to this view, empathy and perspective-taking comprise a complex set of derived relational abilities based on learning to discriminate and respond verbally to ever more complex relations between self, others, place, and time, and through established relations.

Philosophical and psychological roots

Discussions of theory of mind have their roots in philosophical debate from the time of René Descartes' Second Meditation, which set the groundwork for considering the science of the mind.

Two contrasting approaches in the philosophical literature to theory of mind are theory-theory and simulation theory. The theory-theorist posits a veritable theory—"folk psychology"—that people use to reason about others' minds. Such a theory is developed automatically and innately, though it is instantiated through social interactions. It is also closely related to person perception and attribution theory from social psychology.

It is common and intuitive to assume that others are minded. People anthropomorphize non-human animals, inanimate objects, and even natural phenomena. Daniel Dennett referred to this tendency as taking an "intentional stance" toward things: we assume they have intentions, to help predict their future behavior. However, there is an important distinction between taking an "intentional stance" toward something and entering a "shared world" with it. The intentional stance is a functional relationship, describing the use of a theory due to its practical utility, rather than the accuracy of its representation of the world. As such, it is something people resort to during interpersonal interactions. A shared world is directly perceived and its existence structures reality itself for the perceiver. It is not just a lens, through which the perceiver views the world; it in many ways constitutes the cognition, as both its object and the blueprint used to structure perception into understanding.

The philosophical roots of another perspective, the relational frame theory (RFT) account of theory of mind, arise from contextual psychology, which refers to the study of organisms (both human and non-human) interacting in and with a historical and current situational context. It is an approach based on contextualism, a philosophy in which any event is interpreted as an ongoing act inseparable from its current and historical context and in which a radically functional approach to truth and meaning is adopted. As a variant of contextualism, RFT focuses on the construction of practical, scientific knowledge. This scientific form of contextual psychology is virtually synonymous with the philosophy of operant psychology.

Development

The study of which animals are capable of attributing knowledge and mental states to others, as well as the development of this ability in human ontogeny and phylogeny, identifies several behavioral precursors to theory of mind. Understanding attention, understanding of others' intentions, and imitative experience with others are hallmarks of a theory of mind that may be observed early in the development of what later becomes a full-fledged theory.

Simon Baron-Cohen proposed that infants' understanding of attention in others acts as a critical precursor to the development of theory of mind. Understanding attention involves understanding that seeing can be directed selectively as attention, that the looker assesses the seen object as "of interest", and that seeing can induce beliefs. A possible illustration of theory of mind in infants is joint attention. Joint attention refers to when two people look at and attend to the same thing. Parents often use the act of pointing to prompt infants to engage in joint attention; understanding this prompt requires that infants take into account another person's mental state and understand that the person notices an object or finds it of interest. Baron-Cohen speculates that the inclination to spontaneously reference an object in the world as of interest, via pointing, ("Proto declarative pointing") and to likewise appreciate the directed attention of another, may be the underlying motive behind all human communication.

Understanding others' intentions is another critical precursor to understanding other minds because intentionality is a fundamental feature of mental states and events. The "intentional stance" was defined by Daniel Dennett as an understanding that others' actions are goal-directed and arise from particular beliefs or desires. Both two and three-year-old children could discriminate when an experimenter intentionally or accidentally marked a box with stickers. Even earlier in development, Andrew N. Meltzoff found that 18-month-old infants could perform target tasks involving the manipulation of objects that adult experimenters attempted and failed, suggesting the infants could represent the object-manipulating behavior of adults as involving goals and intentions. While attribution of intention and knowledge is investigated in young humans and nonhuman animals to detect precursors to a theory of mind, Gagliardi et al. have pointed out that even adult humans do not always act in a way consistent with an attributional perspective (i.e., based on attribution of knowledge to others). In their experiment, adult human subjects attempted to choose the container baited with a small object from a selection of four containers when guided by confederates who could not see which container was baited.

Research in developmental psychology suggests that an infant's ability to imitate others lies at the origins of both theory of mind and other social-cognitive achievements like perspective-taking and empathy. According to Meltzoff, the infant's innate understanding that others are "like me" allows them to recognize the equivalence between the physical and mental states apparent in others and those felt by the self. For example, the infant uses their own experiences, orienting their head and eyes toward an object of interest to understand the movements of others who turn toward an object; that is, they will generally attend to objects of interest or significance. Some researchers in comparative disciplines have hesitated to put too much weight on imitation as a critical precursor to advanced human social-cognitive skills like mentalizing and empathizing, especially if true imitation is no longer employed by adults. A test of imitation by Alexandra Horowitz found that adult subjects imitated an experimenter demonstrating a novel task far less closely than children did. Horowitz points out that the precise psychological state underlying imitation is unclear and cannot, by itself, be used to draw conclusions about the mental states of humans.

While much research has been done on infants, theory of mind develops continuously throughout childhood and into late adolescence as the synapses in the prefrontal cortex develop. The prefrontal cortex is thought to be involved in planning and decision-making. Children seem to develop theory of mind skills sequentially. The first skill to develop is the ability to recognize that others have diverse desires. Children are able to recognize that others have diverse beliefs soon after. The next skill to develop is recognizing that others have access to different knowledge bases. Finally, children are able to understand that others may have false beliefs and that others are capable of hiding emotions. While this sequence represents the general trend in skill acquisition, it seems that more emphasis is placed on some skills in certain cultures, leading to more valued skills to develop before those that are considered not as important. For example, in individualistic cultures such as the United States, a greater emphasis is placed on the ability to recognize that others have different opinions and beliefs. In a collectivistic culture, such as China, this skill may not be as important and therefore may not develop until later.

Language

There is evidence that the development of theory of mind is closely intertwined with language development in humans. One meta-analysis showed a moderate to strong correlation (r = 0.43) between performance on theory of mind and language tasks. Both language and theory of mind begin to develop around the same time in children (between ages two and five), but many other abilities develop during this same time period as well, and they do not produce such high correlations with one another nor with theory of mind.

Pragmatic theories of communication assume that infants must possess an understanding of beliefs and mental states of others to infer the communicative content that proficient language users intend to convey. Since spoken phrases can have different meanings depending on context, theory of mind can play a crucial role in understanding the intentions of others and inferring the meaning of words. Some empirical results suggest that even 13-month-old infants have an early capacity for communicative mind-reading that enables them to infer what relevant information is transferred between communicative partners, which implies that human language relies at least partially on theory of mind skills.

Carol A. Miller posed further possible explanations for this relationship. Perhaps the extent of verbal communication and conversation involving children in a family could explain theory of mind development. Such language exposure could help introduce a child to the different mental states and perspectives of others. Empirical findings indicate that participation in family discussion predicts scores on theory of mind tasks, and that deaf children who have hearing parents and may not be able to communicate with their parents much during early years of development tend to score lower on theory of mind tasks.

Another explanation of the relationship between language and theory of mind development has to do with a child's understanding of mental-state words such as "think" and "believe". Since a mental state is not something that one can observe from behavior, children must learn the meanings of words denoting mental states from verbal explanations alone, requiring knowledge of the syntactic rules, semantic systems, and pragmatics of a language. Studies have shown that understanding of these mental state words predicts theory of mind in four-year-olds.

A third hypothesis is that the ability to distinguish a whole sentence ("Jimmy thinks the world is flat") from its embedded complement ("the world is flat") and understand that one can be true while the other can be false is related to theory of mind development. Recognizing these complements as being independent of one another is a relatively complex syntactic skill and correlates with increased scores on theory of mind tasks in children.

There is also evidence that the areas of the brain responsible for language and theory of mind are closely connected. The temporoparietal junction (TPJ) is involved in the ability to acquire new vocabulary, as well as to perceive and reproduce words. The TPJ also contains areas that specialize in recognizing faces, voices, and biological motion, and in theory of mind. Since all of these areas are located so closely together, it is reasonable to suspect that they work together. Studies have reported an increase in activity in the TPJ when patients are absorbing information through reading or images regarding other peoples' beliefs but not while observing information about physical control stimuli.

Theory of mind in adults

Neurotypical adults have theory of mind concepts that they developed as children (concepts such as belief, desire, knowledge, and intention). They use these concepts to meet the diverse demands of social life, ranging from snap decisions about how to trick an opponent in a competitive game, to keeping up with who knows what in a fast-moving conversation, to judging the guilt or innocence of the accused in a court of law.

Boaz Keysar, Dale Barr, and colleagues found that adults often failed to use their theory of mind abilities to interpret a speaker's message, and acted as if unaware that the speaker lacked critical knowledge about a task. In one study, a confederate instructed adult participants to rearrange objects, some of which were not visible to the confederate, as part of a communication game. Only objects that were visible to both the confederate and the participant were part of the game. Despite knowing that the confederate could not see some of the objects, a third of the participants still tried to move those objects. Other studies show that adults are prone to egocentric biases, with which they are influenced by their own beliefs, knowledge, or preferences when judging those of other people, or that they neglect other people's perspectives entirely. There is also evidence that adults with greater memory, inhibitory capacity, and motivation are more likely to use their theory of mind abilities.

In contrast, evidence about indirect effects of thinking about other people's mental states suggests that adults may sometimes use their theory of mind automatically. Agnes Kovacs and colleagues measured the time it took adults to detect the presence of a ball as it was revealed from behind an occluder. They found that adults' speed of response was influenced by whether another person (the "agent") in the scene thought there was a ball behind the occluder, even though adults were not asked to pay attention to what the agent thought.

Dana Samson and colleagues measured the time it took adults to judge the number of dots on the wall of a room. They found that adults responded more slowly when another person standing in the room happened to see fewer dots than they did, even when they had never been asked to pay attention to what the person could see. It has been questioned whether these "altercentric biases" truly reflect automatic processing of what another person is thinking or seeing or, instead, reflect attention and memory effects cued by the other person, but not involving any representation of what they think or see.

Different theories seek to explain such results. If theory of mind is automatic, this would help explain how people keep up with the theory of mind demands of competitive games and fast-moving conversations. It might also explain evidence that human infants and some non-human species sometimes appear capable of theory of mind, despite their limited resources for memory and cognitive control. If theory of mind is effortful and not automatic, on the other hand, this explains why it feels effortful to decide whether a defendant is guilty or whether a negotiator is bluffing. Economy of effort would help explain why people sometimes neglect to use their theory of mind.

Ian Apperly and Stephen Butterfill suggested that people have "two systems" for theory of mind, in common with "two systems" accounts in many other areas of psychology. In this account, "system 1" is cognitively efficient and enables theory of mind for a limited but useful set of circumstances. "System 2" is cognitively effortful, but enables much more flexible theory of mind abilities. Philosopher Peter Carruthers disagrees, arguing that the same core theory of mind abilities can be used in both simple and complex ways. The account has been criticized by Celia Heyes who suggests that "system 1" theory of mind abilities do not require representation of mental states of other people, and so are better thought of as "sub-mentalizing".

Aging

In older age, theory of mind capacities decline, irrespective of how exactly they are tested. However, the decline in other cognitive functions is even stronger, suggesting that social cognition is better preserved. In contrast to theory of mind, empathy shows no impairments in aging.

There are two kinds of theory of mind representations: cognitive (concerning mental states, beliefs, thoughts, and intentions) and affective (concerning the emotions of others). Cognitive theory of mind is further separated into first order (e.g., I think she thinks that) and second order (e.g. he thinks that she thinks that). There is evidence that cognitive and affective theory of mind processes are functionally independent from one another. In studies of Alzheimer's disease, which typically occurs in older adults, patients display impairment with second order cognitive theory of mind, but usually not with first order cognitive or affective theory of mind. However, it is difficult to discern a clear pattern of theory of mind variation due to age. There have been many discrepancies in the data collected thus far, likely due to small sample sizes and the use of different tasks that only explore one aspect of theory of mind. Many researchers suggest that theory of mind impairment is simply due to the normal decline in cognitive function.

Cultural variations

Researchers propose that five key aspects of theory of mind develop sequentially for all children between the ages of three and five: diverse desires, diverse beliefs, knowledge access, false beliefs, and hidden emotions. Australian, American, and European children acquire theory of mind in this exact order, and studies with children in Canada, India, Peru, Samoa, and Thailand indicate that they all pass the false belief task at around the same time, suggesting that children develop theory of mind consistently around the world.

However, children from Iran and China develop theory of mind in a slightly different order. Although they begin the development of theory of mind around the same time, toddlers from these countries understand knowledge access before Western children but take longer to understand diverse beliefs. Researchers believe this swap in the developmental order is related to the culture of collectivism in Iran and China, which emphasizes interdependence and shared knowledge as opposed to the culture of individualism in Western countries, which promotes individuality and accepts differing opinions. Because of these different cultural values, Iranian and Chinese children might take longer to understand that other people have different beliefs and opinions. This suggests that the development of theory of mind is not universal and solely determined by innate brain processes but also influenced by social and cultural factors.

Historiography

Theory of mind can help historians to more properly understand historical figures' characters, for example Thomas Jefferson. Emancipationists like Douglas L. Wilson and scholars at the Thomas Jefferson Foundation view Jefferson as an opponent of slavery all his life, noting Jefferson's attempts within the limited range of options available to him to undermine slavery, his many attempts at abolition legislation, the manner in which he provided for slaves, and his advocacy of their more humane treatment. This view contrasts with that of revisionists like Paul Finkelman, who criticizes Jefferson for racism, slavery, and hypocrisy. Emancipationist views on this hypocrisy recognize that if he tried to be true to his word, it would have alienated his fellow Virginians. In another example, Franklin D. Roosevelt did not join NAACP leaders in pushing for federal anti-lynching legislation, as he believed that such legislation was unlikely to pass and that his support for it would alienate Southern congressmen, including many of Roosevelt's fellow Democrats.

Empirical investigation

Whether children younger than three or four years old have a theory of mind is a topic of debate among researchers. It is a challenging question, due to the difficulty of assessing what pre-linguistic children understand about others and the world. Tasks used in research into the development of theory of mind must take into account the umwelt of the pre-verbal child.

False-belief task

One of the most important milestones in theory of mind development is the ability to attribute false belief: in other words, to understand that other people can believe things which are not true. To do this, it is suggested, one must understand how knowledge is formed, that people's beliefs are based on their knowledge, that mental states can differ from reality, and that people's behavior can be predicted by their mental states. Numerous versions of false-belief task have been developed, based on the initial task created by Wimmer and Perner (1983).

In the most common version of the false-belief task (often called the Sally-Anne test), children are told a story about Sally and Anne. Sally has a marble, which she places into her basket, and then leaves the room. While she is out of the room, Anne takes the marble from the basket and puts it into the box. The child being tested is then asked where Sally will look for the marble once she returns. The child passes the task if she answers that Sally will look in the basket, where Sally put the marble; the child fails the task if she answers that Sally will look in the box. To pass the task, the child must be able to understand that another's mental representation of the situation is different from their own, and the child must be able to predict behavior based on that understanding. Another example depicts a boy who leaves chocolate on a shelf and then leaves the room. His mother puts it in the fridge. To pass the task, the child must understand that the boy, upon returning, holds the false belief that his chocolate is still on the shelf.

The results of research using false-belief tasks have been fairly consistent: most typically developing children are able to pass the tasks from around age four. While most children, including those with Down syndrome, are able to pass this test, in one study, 80% of children diagnosed with autism were unable to do so. However, several later studies did not replicate this result.

Adults may also struggle with false beliefs, for instance when they show hindsight bias. In one experiment, adult subjects who were asked for an independent assessment were unable to disregard information on actual outcome. Also in experiments with complicated situations, when assessing others' thinking, adults can fail to correctly disregard certain information that they have been given.

Unexpected contents

Other tasks have been developed to try to extend the false-belief task. In the "unexpected contents" or "smarties" task, experimenters ask children what they believe to be the contents of a box that looks as though it holds Smarties. After the child guesses "Smarties", it is shown that the box in fact contained pencils. The experimenter then re-closes the box and asks the child what she thinks another person, who has not been shown the true contents of the box, will think is inside. The child passes the task if he/she responds that another person will think that "Smarties" exist in the box, but fails the task if she responds that another person will think that the box contains pencils. Gopnik & Astington found that children pass this test at age four or five years.

Other tasks

The "false-photograph" task also measures theory of mind development. In this task, children must reason about what is represented in a photograph that differs from the current state of affairs. Within the false-photograph task, either a location or identity change exists. In the location-change task, the examiner puts an object in one location (e.g. chocolate in an open green cupboard), whereupon the child takes a Polaroid photograph of the scene. While the photograph is developing, the examiner moves the object to a different location (e.g. a blue cupboard), allowing the child to view the examiner's action. The examiner asks the child two control questions: "When we first took the picture, where was the object?" and "Where is the object now?" The subject is also asked a "false-photograph" question: "Where is the object in the picture?" The child passes the task if he/she correctly identifies the location of the object in the picture and the actual location of the object at the time of the question. However, the last question might be misinterpreted as "Where in this room is the object that the picture depicts?" and therefore some examiners use an alternative phrasing.

To make it easier for animals, young children, and individuals with classical autism to understand and perform theory of mind tasks, researchers have developed tests in which verbal communication is de-emphasized: some whose administration does not involve verbal communication on the part of the examiner, some whose successful completion does not require verbal communication on the part of the subject, and some that meet both of those standards. One category of tasks uses a preferential-looking paradigm, with looking time as the dependent variable. For instance, nine-month-old infants prefer looking at behaviors performed by a human hand over those made by an inanimate hand-like object. Other paradigms look at rates of imitative behavior, the ability to replicate and complete unfinished goal-directed acts, and rates of pretend play.

Early precursors

Research on the early precursors of theory of mind has invented ways to observe preverbal infants' understanding of other people's mental states, including perception and beliefs. Using a variety of experimental procedures, studies show that infants from their first year of life have an implicit understanding of what other people see and what they know. A popular paradigm used to study infants' theory of mind is the violation-of-expectation procedure, which exploits infants' tendency to look longer at unexpected and surprising events compared to familiar and expected events. The amount of time they look at an event gives researchers an indication of what infants might be inferring, or their implicit understanding of events. One study using this paradigm found that 16-month-olds tend to attribute beliefs to a person whose visual perception was previously witnessed as being "reliable", compared to someone whose visual perception was "unreliable". Specifically, 16-month-olds were trained to expect a person's excited vocalization and gaze into a container to be associated with finding a toy in the reliable-looker condition or an absence of a toy in the unreliable-looker condition. Following this training phase, infants witnessed, in an object-search task, the same persons searching for a toy either in the correct or incorrect location after they both witnessed the location of where the toy was hidden. Infants who experienced the reliable looker were surprised and therefore looked longer when the person searched for the toy in the incorrect location compared to the correct location. In contrast, the looking time for infants who experienced the unreliable looker did not differ for either search locations. These findings suggest that 16-month-old infants can differentially attribute beliefs about a toy's location based on the person's prior record of visual perception.

Methodological problems

With the methods used to test theory of mind, it has been experimentally shown that very simple robots that only react by reflexes and are not built to have any complex cognition at all can pass the tests for having theory of mind abilities that psychology textbooks assume to be exclusive to humans older than four or five years. Whether such a robot passes the test is influenced by completely non-cognitive factors such as placement of objects and the structure of the robot body influencing how the reflexes are conducted. It has therefore been suggested that theory of mind tests may not actually test cognitive abilities.

Furthermore, early research into theory of mind in autistic children is argued to constitute epistemological violence due to implicit or explicit negative and universal conclusions about autistic individuals being drawn from empirical data that viably supports other (non-universal) conclusions.

Deficits

Theory of mind impairment, or mind-blindness, describes a difficulty someone would have with perspective-taking. Individuals with theory of mind impairment struggle to see phenomena from any other perspective than their own. Individuals who experience a theory of mind deficit have difficulty determining the intentions of others, lack understanding of how their behavior affects others, and have a difficult time with social reciprocity. Theory of mind deficits have been observed in people with autism spectrum disorders, schizophrenia, nonverbal learning disorder and along with people under the influence of alcohol and narcotics, sleep-deprived people, and people who are experiencing severe emotional or physical pain. Theory of mind deficits have also been observed in deaf children who are late signers (i.e. are born to hearing parents), but such a deficit is due to the delay in language learning, not any cognitive deficit, and therefore disappears once the child learns sign language.

Autism

In 1985 Simon Baron-Cohen, Alan M. Leslie, and Uta Frith suggested that children with autism do not employ theory of mind and that autistic children have particular difficulties with tasks requiring the child to understand another person's beliefs. These difficulties persist when children are matched for verbal skills and they have been taken as a key feature of autism. Although in a 2019 review, Gernsbacher and Yergeau argued that "the claim that autistic people lack a theory of mind is empirically questionable", as there have been numerous failed replications of classic ToM studies and the meta-analytical effect sizes of such replications were minimal to small.

Many individuals classified as autistic have severe difficulty assigning mental states to others, and some seem to lack theory of mind capabilities. Researchers who study the relationship between autism and theory of mind attempt to explain the connection in a variety of ways. One account assumes that theory of mind plays a role in the attribution of mental states to others and in childhood pretend play. According to Leslie, theory of mind is the capacity to mentally represent thoughts, beliefs, and desires, regardless of whether the circumstances involved are real. This might explain why some autistic individuals show extreme deficits in both theory of mind and pretend play. However, Hobson proposes a social-affective justification, in which deficits in theory of mind in autistic people result from a distortion in understanding and responding to emotions. He suggests that typically developing individuals, unlike autistic individuals, are born with a set of skills (such as social referencing ability) that later lets them comprehend and react to other people's feelings. Other scholars emphasize that autism involves a specific developmental delay, so that autistic children vary in their deficiencies, because they experience difficulty in different stages of growth. Very early setbacks can alter proper advancement of joint-attention behaviors, which may lead to a failure to form a full theory of mind.

It has been speculated that theory of mind exists on a continuum as opposed to the traditional view of a discrete presence or absence. While some research has suggested that some autistic populations are unable to attribute mental states to others, recent evidence points to the possibility of coping mechanisms that facilitate the attribution of mental states. A binary view regarding theory of mind contributes to the stigmatization of autistic adults who do possess perspective-taking capacity, as the assumption that autistic people do not have empathy can become a rationale for dehumanization.

Tine et al. report that autistic children score substantially lower on measures of social theory of mind (i.e., "reasoning about others' mental states", p. 1) in comparison to children diagnosed with Asperger syndrome.

Generally, children with more advanced theory of mind abilities display more advanced social skills, greater adaptability to new situations, and greater cooperation with others. As a result, these children are typically well-liked. However, "children may use their mind-reading abilities to manipulate, outwit, tease, or trick their peers." Individuals possessing inferior theory of mind skills, such as children with autism spectrum disorder, may be socially rejected by their peers since they are unable to communicate effectively. Social rejection has been proven to negatively impact a child's development and can put the child at greater risk of developing depressive symptoms.

Peer-mediated interventions (PMI) are a school-based treatment approach for children and adolescents with autism spectrum disorder in which peers are trained to be role models in order to promote social behavior. Laghi et al. studied whether analysis of prosocial (nice) and antisocial (nasty) theory-of-mind behaviors could be used, in addition to teacher recommendations, to select appropriate candidates for PMI programs. Selecting children with advanced theory-of-mind skills who use them in prosocial ways will theoretically make the program more effective. While the results indicated that analyzing the social uses of theory of mind of possible candidates for a PMI program may increase the program's efficacy, it may not be a good predictor of a candidate's performance as a role model.

A 2014 Cochrane review on interventions based on theory of mind found that such a theory could be taught to individuals with autism but claimed little evidence of skill maintenance, generalization to other settings, or development effects on related skills.

Some 21st century studies have shown that the results of some studies of theory of mind tests on autistic people may be misinterpreted based on the double empathy problem, which proposes that rather than autistic people specifically having trouble with theory of mind, autistic people and non-autistic people have equal difficulty understanding one-another due to their neurological differences. Studies have shown that autistic adults perform better in theory of mind tests when paired with other autistic adults as well as possibly autistic close family members. Academics who acknowledge the double empathy problem also propose that it is likely autistic people understand non-autistic people to a higher degree than vice-versa, due to the necessity of functioning in a non-autistic society.

Psychopathy

Psychopathy is another deficit that is of large importance when discussing theory of mind. While psychopathic individuals show impaired emotional behavior including a lack of emotional responsiveness to others and deficient empathy, as well as impaired social behavior, there are many controversies regarding psychopathic individuals' theory of mind. Many different studies provide contradictory information on a correlation between theory of mind impairment and psychopathic individuals.

There have been some speculations made about the similarities between individuals with autism and psychopathic individuals in the theory of mind performance. In this study in 2008, the Happé's advanced test of theory of mind was presented to a group of 25 psychopaths, and 25 non-psychopaths incarcerated. This test showed that there wasn’t a difference in the performance of the task for the psychopaths and non-psychopaths. However, they were able to see that the psychopaths were performing significantly better than the most highly able adult autistic population. This shows that there is not a similarity between individuals with autism and psychopathic individuals.

There have been repetitive suggestions regarding the possibility that a deficient or biased grasp of others’ mental states, or theory of mind, could potentially contribute to antisocial behavior, aggression, and psychopathy. In one study named ‘Reading the Mind in the Eyes’, the participants view photographs of an individual’s eye and had to attribute a mental state, or emotion, to the individual. This is an interesting test because Magnetic resonance imaging studies showed that this task produced increased activity in the dorsolateral prefrontal and the left medial frontal cortices, the superior temporal gyrus, and the left amygdala. There is extensive literature suggesting amygdala dysfunction in psychopathy however, this test shows that both groups of psychopathic and non-psychopathic adults performed equally well on the test. Thus, disregarding that there isn’t Theory of Mind impairment in psychopathic individuals.

In another study using a systemic review and meta-analysis, data was gathered from 42 different studies and found that psychopathic traits are associated with impairment in the theory of mind task performance. This relationship was not regulated by age, population, psychopathy measurement (self-report versus clinical checklist) or theory of mind task type (cognitive versus affective). This study used past studies to show that there is a relationship between psychopathic individuals and theory of mind impairments.

In 2009 a study was conducted to test whether impairment in the emotional aspects of theory of mind rather that the general theory of mind abilities may account for some of the impaired social behavior in psychopathy. This study involved criminal offenders diagnosed with antisocial personality disorder who had high psychopathy features, participants with localized lesions in the orbitofrontal cortex, participants with non-frontal lesions, and healthy control subjects. Subjects were tested with a task that examines affective versus cognitive theory of mind. They found that the individuals with psychopathy and those with orbitofrontal cortex lesions were both impaired on the affective theory of mind but not in cognitive theory of mind when compared to the control group.

Schizophrenia

Individuals diagnosed with schizophrenia can show deficits in theory of mind. Mirjam Sprong and colleagues investigated the impairment by examining 29 different studies, with a total of over 1500 participants. This meta-analysis showed significant and stable deficit of theory of mind in people with schizophrenia. They performed poorly on false-belief tasks, which test the ability to understand that others can hold false beliefs about events in the world, and also on intention-inference tasks, which assess the ability to infer a character's intention from reading a short story. Schizophrenia patients with negative symptoms, such as lack of emotion, motivation, or speech, have the most impairment in theory of mind and are unable to represent the mental states of themselves and of others. Paranoid schizophrenic patients also perform poorly because they have difficulty accurately interpreting others' intentions. The meta-analysis additionally showed that IQ, gender, and age of the participants do not significantly affect the performance of theory of mind tasks.

Research suggests that impairment in theory of mind negatively affects clinical insight—the patient's awareness of their mental illness. Insight requires theory of mind; a patient must be able to adopt a third-person perspective and see the self as others do. A patient with good insight can accurately self-represent, by comparing himself with others and by viewing himself from the perspective of others. Insight allows a patient to recognize and react appropriately to his symptoms. A patient who lacks insight does not realize that he has a mental illness, because of his inability to accurately self-represent. Therapies that teach patients perspective-taking and self-reflection skills can improve abilities in reading social cues and taking the perspective of another person.

Research indicates that theory-of-mind deficit is a stable trait-characteristic rather than a state-characteristic of schizophrenia. The meta-analysis conducted by Sprong et al. showed that patients in remission still had impairment in theory of mind. This indicates that the deficit is not merely a consequence of the active phase of schizophrenia.

Schizophrenic patients' deficit in theory of mind impairs their interactions with others. Theory of mind is particularly important for parents, who must understand the thoughts and behaviors of their children and react accordingly. Dysfunctional parenting is associated with deficits in the first-order theory of mind, the ability to understand another person's thoughts, and in the second-order theory of mind, the ability to infer what one person thinks about another person's thoughts. Compared with healthy mothers, mothers with schizophrenia are found to be more remote, quiet, self-absorbed, insensitive, unresponsive, and to have fewer satisfying interactions with their children. They also tend to misinterpret their children's emotional cues, and often misunderstand neutral faces as negative. Activities such as role-playing and individual or group-based sessions are effective interventions that help the parents improve on perspective-taking and theory of mind. There is a strong association between theory of mind deficit and parental role dysfunction.

Alcohol use disorders

Impairments in theory of mind, as well as other social-cognitive deficits, are commonly found in people who have alcohol use disorders, due to the neurotoxic effects of alcohol on the brain, particularly the prefrontal cortex.

Depression and dysphoria

Individuals in a major depressive episode, a disorder characterized by social impairment, show deficits in theory of mind decoding. Theory of mind decoding is the ability to use information available in the immediate environment (e.g., facial expression, tone of voice, body posture) to accurately label the mental states of others. The opposite pattern, enhanced theory of mind, is observed in individuals vulnerable to depression, including those individuals with past major depressive disorder (MDD), dysphoric individuals, and individuals with a maternal history of MDD.

Developmental language disorder

Children diagnosed with developmental language disorder (DLD) exhibit much lower scores on reading and writing sections of standardized tests, yet have a normal nonverbal IQ. These language deficits can be any specific deficits in lexical semantics, syntax, or pragmatics, or a combination of multiple problems. Such children often exhibit poorer social skills than normally developing children, and seem to have problems decoding beliefs in others. A recent meta-analysis confirmed that children with DLD have substantially lower scores on theory of mind tasks compared to typically developing children. This strengthens the claim that language development is related to theory of mind.

Brain mechanisms

In neurotypical people

Research on theory of mind in autism led to the view that mentalizing abilities are subserved by dedicated mechanisms that can—in some cases—be impaired while general cognitive function remains largely intact.

Neuroimaging research supports this view, demonstrating specific brain regions are consistently engaged during theory of mind tasks. Positron emission tomography (PET) research on theory of mind, using verbal and pictorial story comprehension tasks, identifies a set of brain regions including the medial prefrontal cortex (mPFC), and area around posterior superior temporal sulcus (pSTS), and sometimes precuneus and amygdala/temporopolar cortex. Research on the neural basis of theory of mind has diversified, with separate lines of research focusing on the understanding of beliefs, intentions, and more complex properties of minds such as psychological traits.

Studies from Rebecca Saxe's lab at MIT, using a false-belief versus false-photograph task contrast aimed at isolating the mentalizing component of the false-belief task, have consistently found activation in the mPFC, precuneus, and temporoparietal junction (TPJ), right-lateralized. In particular, Saxe et al. proposed that the right TPJ (rTPJ) is selectively involved in representing the beliefs of others. Some debate exists, as the same rTPJ region is consistently activated during spatial reorienting of visual attention; Jean Decety from the University of Chicago and Jason Mitchell from Harvard thus propose that the rTPJ subserves a more general function involved in both false-belief understanding and attentional reorienting, rather than a mechanism specialized for social cognition. However, it is possible that the observation of overlapping regions for representing beliefs and attentional reorienting may simply be due to adjacent, but distinct, neuronal populations that code for each. The resolution of typical fMRI studies may not be good enough to show that distinct/adjacent neuronal populations code for each of these processes. In a study following Decety and Mitchell, Saxe and colleagues used higher-resolution fMRI and showed that the peak of activation for attentional reorienting is approximately 6–10 mm above the peak for representing beliefs. Further corroborating that differing populations of neurons may code for each process, they found no similarity in the patterning of fMRI response across space.

Using single-cell recordings in the human dorsomedial prefrontal cortex (dmPFC), researchers at MGH identified neurons that encode information about others' beliefs, which were distinct from self-beliefs, across different scenarios in a false-belief task. They further showed that these neurons could provide detailed information about others' beliefs, and could accurately predict these beliefs' verity. These findings suggest a prominent role of distinct neuronal populations in the dmPFC in theory of mind complemented by the TPJ and pSTS.

Functional imaging also illuminates the detection of mental state information in animations of moving geometric shapes similar to those used in Heider and Simmel (1944), which typical humans automatically perceive as social interactions laden with intention and emotion. Three studies found remarkably similar patterns of activation during the perception of such animations versus a random or deterministic motion control: mPFC, pSTS, fusiform face area (FFA), and amygdala were selectively engaged during the theory of mind condition. Another study presented subjects with an animation of two dots moving with a parameterized degree of intentionality (quantifying the extent to which the dots chased each other), and found that pSTS activation correlated with this parameter.

A separate body of research implicates the posterior superior temporal sulcus in the perception of intentionality in human action. This area is also involved in perceiving biological motion, including body, eye, mouth, and point-light display motion. One study found increased pSTS activation while watching a human lift his hand versus having his hand pushed up by a piston (intentional versus unintentional action). Several studies found increased pSTS activation when subjects perceive a human action that is incongruent with the action expected from the actor's context and inferred intention. Examples would be: a human performing a reach-to-grasp motion on empty space next to an object, versus grasping the object; a human shifting eye gaze toward empty space next to a checkerboard target versus shifting gaze toward the target; an unladen human turning on a light with his knee, versus turning on a light with his knee while carrying a pile of books; and a walking human pausing as he passes behind a bookshelf, versus walking at a constant speed. In these studies, actions in the "congruent" case have a straightforward goal, and are easy to explain in terms of the actor's intention. The incongruent actions, on the other hand, require further explanation (why would someone twist empty space next to a gear?), and apparently demand more processing in the STS. This region is distinct from the temporoparietal area activated during false belief tasks. pSTS activation in most of the above studies was largely right-lateralized, following the general trend in neuroimaging studies of social cognition and perception. Also right-lateralized are the TPJ activation during false belief tasks, the STS response to biological motion, and the FFA response to faces.

Neuropsychological evidence supports neuroimaging results regarding the neural basis of theory of mind. Studies with patients with a lesion of the frontal lobes and the temporoparietal junction of the brain (between the temporal lobe and parietal lobe) report that they have difficulty with some theory of mind tasks. This shows that theory of mind abilities are associated with specific parts of the human brain. However, the fact that the medial prefrontal cortex and temporoparietal junction are necessary for theory of mind tasks does not imply that these regions are specific to that function. TPJ and mPFC may subserve more general functions necessary for Theory of Mind.

Research by Vittorio Gallese, Luciano Fadiga, and Giacomo Rizzolatti shows that some sensorimotor neurons, referred to as mirror neurons and first discovered in the premotor cortex of rhesus monkeys, may be involved in action understanding. Single-electrode recording revealed that these neurons fired when a monkey performed an action, as well as when the monkey viewed another agent performing the same action. fMRI studies with human participants show brain regions (assumed to contain mirror neurons) that are active when one person sees another person's goal-directed action. These data led some authors to suggest that mirror neurons may provide the basis for theory of mind in the brain, and to support simulation theory of mind reading.

There is also evidence against a link between mirror neurons and theory of mind. First, macaque monkeys have mirror neurons but do not seem to have a 'human-like' capacity to understand theory of mind and belief. Second, fMRI studies of theory of mind typically report activation in the mPFC, temporal poles, and TPJ or STS, but those brain areas are not part of the mirror neuron system. Some investigators, like developmental psychologist Andrew Meltzoff and neuroscientist Jean Decety, believe that mirror neurons merely facilitate learning through imitation and may provide a precursor to the development of theory of mind. Others, like philosopher Shaun Gallagher, suggest that mirror-neuron activation, on a number of counts, fails to meet the definition of simulation as proposed by the simulation theory of mindreading.

In autism

Several neuroimaging studies have looked at the neural basis for theory of mind impairment in subjects with Asperger syndrome and high-functioning autism (HFA). The first PET study of theory of mind in autism (also the first neuroimaging study using a task-induced activation paradigm in autism) replicated a prior study in neurotypical individuals, which employed a story-comprehension task. This study found displaced and diminished mPFC activation in subjects with autism. However, because the study used only six subjects with autism, and because the spatial resolution of PET imaging is relatively poor, these results should be considered preliminary.

A subsequent fMRI study scanned normally developing adults and adults with HFA while performing a "reading the mind in the eyes" task: viewing a photo of a human's eyes and choosing which of two adjectives better describes the person's mental state, versus a gender discrimination control. The authors found activity in orbitofrontal cortex, STS, and amygdala in normal subjects, and found less amygdala activation and abnormal STS activation in subjects with autism.

A more recent PET study looked at brain activity in individuals with HFA and Asperger syndrome while viewing Heider-Simmel animations (see above) versus a random motion control. In contrast to normally-developing subjects, those with autism showed little STS or FFA activation, and less mPFC and amygdala activation. Activity in extrastriate regions V3 and LO was identical across the two groups, suggesting intact lower-level visual processing in the subjects with autism. The study also reported less functional connectivity between STS and V3 in the autism group. However decreased temporal correlation between activity in STS and V3 would be expected simply from the lack of an evoked response in STS to intent-laden animations in subjects with autism. A more informative analysis would be to compute functional connectivity after regressing out evoked responses from all-time series.

A subsequent study, using the incongruent/congruent gaze-shift paradigm described above, found that in high-functioning adults with autism, posterior STS (pSTS) activation was undifferentiated while they watched a human shift gaze toward a target and then toward adjacent empty space. The lack of additional STS processing in the incongruent state may suggest that these subjects fail to form an expectation of what the actor should do given contextual information, or that feedback about the violation of this expectation does not reach STS. Both explanations involve an impairment or deficit in the ability to link eye gaze shifts with intentional explanations. This study also found a significant anticorrelation between STS activation in the incongruent-congruent contrast and social subscale score on the Autism Diagnostic Interview-Revised, but not scores on the other subscales.

An fMRI study demonstrated that the right temporoparietal junction (rTPJ) of higher-functioning adults with autism was not more selectively activated for mentalizing judgments when compared to physical judgments about self and other. rTPJ selectivity for mentalizing was also related to individual variation on clinical measures of social impairment: individuals whose rTPJ was increasingly more active for mentalizing compared to physical judgments were less socially impaired, while those who showed little to no difference in response to mentalizing or physical judgments were the most socially impaired. This evidence builds on work in typical development that suggests rTPJ is critical for representing mental state information, whether it is about oneself or others. It also points to an explanation at the neural level for the pervasive mind-blindness difficulties in autism that are evident throughout the lifespan.

In schizophrenia

The brain regions associated with theory of mind include the superior temporal gyrus (STS), the temporoparietal junction (TPJ), the medial prefrontal cortex (mPFC), the precuneus, and the amygdala. The reduced activity in the mPFC of individuals with schizophrenia is associated with theory of mind deficit and may explain impairments in social function among people with schizophrenia. Increased neural activity in mPFC is related to better perspective-taking, emotion management, and increased social functioning. Disrupted brain activities in areas related to theory of mind may increase social stress or disinterest in social interaction, and contribute to the social dysfunction associated with schizophrenia.

Practical validity

Group member average scores of theory of mind abilities, measured with the Reading the Mind in the Eyes test (RME), are possibly drivers of successful group performance. High group average scores on the RME are correlated with the collective intelligence factor c, defined as a group's ability to perform a wide range of mental tasks, a group intelligence measure similar to the g factor for general individual intelligence. RME is a theory of mind test for adults that shows sufficient test-retest reliability and constantly differentiates control groups from individuals with functional autism or Asperger syndrome. It is one of the most widely accepted and well-validated tests for theory of mind abilities within adults.

Evolution

The evolutionary origin of theory of mind remains obscure. While many theories make claims about its role in the development of human language and social cognition, few of them specify in detail any evolutionary neurophysiological precursors. One theory claims that theory of mind has its roots in two defensive reactions—immobilization stress and tonic immobility—which are implicated in the handling of stressful encounters and also figure prominently in mammalian childrearing practice. Their combined effect seems capable of producing many of the hallmarks of theory of mind, such as eye-contact, gaze-following, inhibitory control, and intentional attributions.

Non-human

An open question is whether non-human animals have a genetic endowment and social environment that allows them to acquire a theory of mind like human children do. This is a contentious issue because of the difficulty of inferring from animal behavior the existence of thinking or of particular thoughts, or the existence of a concept of self or self-awareness, consciousness, and qualia. One difficulty with non-human studies of theory of mind is the lack of sufficient numbers of naturalistic observations, giving insight into what the evolutionary pressures might be on a species' development of theory of mind.

Non-human research still has a major place in this field. It is especially useful in illuminating which nonverbal behaviors signify components of theory of mind, and in pointing to possible stepping points in the evolution of that aspect of social cognition. While it is difficult to study human-like theory of mind and mental states in species of whose potential mental states we have an incomplete understanding, researchers can focus on simpler components of more complex capabilities. For example, many researchers focus on animals' understanding of intention, gaze, perspective, or knowledge (of what another being has seen). A study that looked at understanding of intention in orangutans, chimpanzees, and children showed that all three species understood the difference between accidental and intentional acts.

Individuals exhibit theory of mind by extrapolating another's internal mental states from their observable behavior. So one challenge in this line of research is to distinguish this from more run-of-the-mill stimulus-response learning, with the other's observable behavior being the stimulus.

Recently, most non-human theory of mind research has focused on monkeys and great apes, who are of most interest in the study of the evolution of human social cognition. Other studies relevant to attributions theory of mind have been conducted using plovers and dogs, which show preliminary evidence of understanding attention—one precursor of theory of mind—in others.

There has been some controversy over the interpretation of evidence purporting to show theory of mind ability—or inability—in animals. For example, Povinelli et al. presented chimpanzees with the choice of two experimenters from whom to request food: one who had seen where food was hidden, and one who, by virtue of one of a variety of mechanisms (having a bucket or bag over his head, a blindfold over his eyes, or being turned away from the baiting) does not know, and can only guess. They found that the animals failed in most cases to differentially request food from the "knower". By contrast, Hare, Call, and Tomasello found that subordinate chimpanzees were able to use the knowledge state of dominant rival chimpanzees to determine which container of hidden food they approached. William Field and Sue Savage-Rumbaugh believe that bonobos have developed theory of mind, and cite their communications with a captive bonobo, Kanzi, as evidence.

In one experiment, ravens (Corvus corax) took into account visual access of unseen conspecifics. The researchers argued that "ravens can generalize from their own perceptual experience to infer the possibility of being seen".

Evolutionary anthropologist Christopher Krupenye studied the existence of theory of mind, and particularly false beliefs, in non-human primates.

Keren Haroush and Ziv Williams outlined the case for a group of neurons in primates' brains that uniquely predicted the choice selection of their interacting partner. These primates' neurons, located in the anterior cingulate cortex of rhesus monkeys, were observed using single-unit recording while the monkeys played a variant of the iterative prisoner's dilemma game. By identifying cells that represent the yet unknown intentions of a game partner, Haroush & Williams' study supports the idea that theory of mind may be a fundamental and generalized process, and suggests that anterior cingulate cortex neurons may act to complement the function of mirror neurons during social interchange.

Maitrī

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