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. notably, 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. adults may also struggle with false beliefs, for instance when they show hindsight bias—"the inclination to see events that have already happened as being more predictable than they were before they took place." 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 a candy called "smarties". after the child guesses (usually) "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 (leo kanner-type) 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 or not such a robot passes or fails 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. 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 attention deficit hyperactivity disorder, 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 or not 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 a spectrum of mindful behavior. 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 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 is invaluable, 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. schizophrenia individuals diagnosed with schizophrenia can show deficits in theory