Theory of mind is the ability to attribute mental states — beliefs, intents, desires, emotions, knowledge,
etc. — to oneself, and to others, and to understand that others have
beliefs, desires, intentions, and perspectives that are different from
one's own. Theory of mind is crucial for everyday human social interactions and is used when analyzing, judging, and inferring others' behaviors. Deficits can occur in people with autism spectrum disorders, schizophrenia, attention deficit hyperactivity disorder, cocaine addiction, and brain damage suffered from alcohol's neurotoxicity. Although philosophical approaches to this exist, the theory of mind as such is distinct from the philosophy of mind.
Definition
Theory of mind is a theory insofar as the mind is the only thing being directly observed.
The presumption that others have a mind is termed a theory of mind
because each human can only intuit the existence of their own mind
through introspection, and no one has direct access to the mind of
another. It is typically assumed that others have minds analogous to
one's own, and this assumption is based on the reciprocal, social
interaction, as observed in joint attention, the functional use of language, and the understanding of others' emotions and actions.
Having theory of mind allows one to attribute thoughts, desires, and
intentions to others, to predict or explain their actions, and to posit
their intentions. As originally defined, it enables one to understand
that mental states can be the cause of—and thus 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, that one must be able to
conceive of the mind as a "generator of representations". If a person does not have a complete 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
theory 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
is a related concept, meaning the recognition and understanding of the
states of mind of others, including their beliefs, desires and
particularly emotions. This is often characterized as the ability to
"put oneself into another's shoes". Recent neuro-ethological studies of animal behaviour suggest that even rodents may exhibit ethical or 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
35 years since Premack and Guy Woodruff's paper, "Does the chimpanzee have a theory of mind?" The emerging field of social neuroscience
has also begun to address this debate, by imaging the brains of humans
while they perform tasks demanding the understanding of an intention,
belief or other mental state in others.
An alternative account of theory of mind is given within operant psychology and provides significant 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 what is called relational frame theory.
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
Contemporary discussions of Theory of Mind have their roots in philosophical debate—most broadly, from the time of Descartes' Second Meditation,
which set the groundwork for considering the science of the mind. Most
prominent recently are two contrasting approaches in the philosophical
literature, to theory of mind: theory-theory and simulation theory.
The theory-theorist imagines a veritable theory—"folk psychology"—used
to reason about others' minds. The theory is developed automatically and
innately, though instantiated through social interactions. It is also closely related to person perception and attribution theory from social psychology.
The intuitive assumption that others are minded is an apparent tendency we all share. We 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 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 detached and functional theory we
resort to during interpersonal interactions. A shared world is directly
perceived and its existence structures reality itself for the perceiver.
It is not just automatically applied to perception; it in many ways
constitutes perception.
The philosophical roots of the relational frame theory (RFT)
account of Theory of Mind arise from contextual psychology and refer 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,
has identified several behavioral precursors to theory of mind.
Understanding attention, understanding of others' intentions, and
imitative experience with other people are hallmarks of a theory of mind
that may be observed early in the development of what later becomes a
full-fledged theory. In studies with non-human animals and pre-verbal
humans, in particular, researchers look to these behaviors
preferentially in making inferences about mind.
Simon Baron-Cohen
identified the infant's understanding of attention in others, a social
skill found by 7 to 9 months of age, 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. Attention
can be directed and shared by the act of pointing, a joint attention
behavior that requires taking into account another person's mental
state, particularly whether 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 ("protodeclarative pointing") and to likewise appreciate
the directed attention and interests of another may be the underlying
motive behind all human communication.
Understanding of others' intentions is another critical precursor
to understanding other minds because intentionality, or "aboutness", is
a fundamental feature of mental states and events. The "intentional
stance" has been defined by Daniel Dennett
as an understanding that others' actions are goal-directed and arise
from particular beliefs or desires. Both 2- and 3-year-old children
could discriminate when an experimenter intentionally vs. accidentally
marked a box with stickers as baited. Even earlier in ontogeny, Andrew N. Meltzoff
found that 18-month-old infants could perform target manipulations 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 (the box-marking) and knowledge
(false-belief tasks) 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.
In the experiment, adult human subjects made choices about baited
containers when guided by confederates who could not see (and therefore,
not know) which container was baited.
Recent research in developmental psychology suggests that the
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 it to recognize the equivalence between the
physical and mental states apparent in others and those felt by the
self. For example, the infant uses his own experiences, orienting his
head/eyes toward an object of interest to understand the movements of
others who turn toward an object, that is, that they will generally
attend to objects of interest or significance. Some researchers in
comparative disciplines have hesitated to put a too-ponderous 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 (neuronal connections) 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 to believe 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.
One might argue that this relationship is due solely to the fact that
both language and theory of mind seem to begin to develop substantially
around the same time in children (between ages 2–5). However, many other
abilities develop during this same time period as well, and do not
produce such high correlations with one another nor with theory of mind.
There must be something else going on to explain the relationship
between theory of mind and language.
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 a verbal utterance is often
underdetermined, and therefore, it can have different meanings depending
on the actual context theory of mind abilities can play a crucial role
in understanding the communicative and informative 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. One idea was that the extent of verbal communication and
conversation involving children in a family could explain theory of mind
development. The belief is that this type of language exposure could
help introduce a child to the different mental states and perspectives
of others.
This has been suggested empirically by findings indicating that
participation in family discussion predict scores on theory of mind
tasks,
as well as findings showing 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 sentential complements as being independent of one another is a
relatively complex syntactic skill and has been shown to be related to
increased scores on theory of mind tasks in children.
In addition to these hypotheses, there is also evidence that the
neural networks between the areas of the brain responsible for language
and theory of mind are closely connected. The temporoparietal junction
has been shown to be involved in the ability to acquire new vocabulary,
as well as perceive and reproduce words. The temporoparietal junction
also contains areas that specialize in recognizing faces, voices, and
biological motion, in addition to theory of mind. Since all of these
areas are located so closely together, it is reasonable to conclude that
they work together. Moreover, 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 the theory of mind concepts that they developed as children
(concepts such as belief, desire, knowledge and intention). A focal
question is how 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, even
though they were perfectly well aware that the speaker lacked critical
knowledge.
Other studies converge in showing that adults are prone to “egocentric
biases”, whereby they are influenced by their own beliefs, knowledge or
preferences when judging those of other people, or else neglect other
people’s perspectives entirely.
There is also evidence that adults with greater memory and inhibitory
capacity and greater motivation are more likely to use their theory of
mind abilities.
In contrast, evidence from tasks looking for 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 or not an avatar in the
scene thought there was a ball behind the occluder, even though adults
were not asked to pay attention to what the avatar 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 an avatar 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 avatar could see.
It has been questioned whether these “altercentric biases” truly
reflect automatic processing of what another person is thinking or
seeing, or whether they instead reflect attention and memory effects
cued by the avatar, but not involving any representation of what they
think or see.
Different theories have sought to explain these patterns of
results. The idea that theory of mind is automatic is attractive because
it 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.
The idea that theory of mind is effortful and not automatic is
attractive because it feels effortful to decide whether a defendant is
guilty or innocent, or whether a negotiator is bluffing, and economy of
effort would help explain why people sometimes neglect to use their
theory of mind. Ian Apperly and Stephen Butterfill have suggested that people do in fact have “two systems” for theory of mind, in common with “two systems” accounts in many other areas of psychology.
On 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. This account has been criticised by Peter Carruthers who
suggests that the same core theory of mind abilities can be used in both
simple and complex ways.
The account has been criticised 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-mentalising”.
Aging
In older
age, theory of mind capacities decline, irrespective of how exactly they
are tested (e.g. stories, eyes, videos, false belief-video, false
belief-other, faux pas).
However, the decline in other cognitive functions is even stronger,
suggesting that social cognition is somewhat preserved. In contrast to
theory of mind, empathy shows no impairments in aging.
There are two kinds of theory of mind representations: cognitive
(concerning the mental states, beliefs, thoughts, and intentions of
others) 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, the 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 the theory of mind impairment is simply
due to the normal decline in cognitive function.
Cultural variations
Researchers
have proposed that five key aspects of theory of mind develop
sequentially for all children between the ages of three to five.
This five-step theory of mind scale consists of the development of
diverse desires (DD), diverse beliefs (DB), knowledge access (KA), false
beliefs (FB), and hidden emotions (HE). 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 the 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 (KA) before Western
children but take longer to understand false beliefs (FB). 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 conflicting
opinions. Because of these different cultural values, Iranian and
Chinese children might take longer to understand that other people have
different, sometimes false, beliefs. 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.
Empirical investigation
Whether
children younger than 3 or 4 years old may have any 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—(the German word Umwelt means "environment" or "surrounding world")—of the pre-verbal child.
False-belief task
One of the most important milestones in theory of mind development is gaining the ability to attribute false belief:
that is, to recognize that others can have beliefs about the world that
are diverging. 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 the
false-belief task have been developed, based on the initial task done by
Wimmer and Perner (1983).
In the most common version of the false-belief task (often called the "'Sally-Anne' test"
or "'Sally-Anne' task"), children are told or shown a story involving
two characters. For example, the child is shown two dolls, Sally and
Anne, who have a basket and a box, respectively. Sally also 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. Sally returns, and the child is then asked where
Sally will look for the marble. 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,
where the child knows the marble is hidden, even though Sally cannot
know this, since she did not see it hidden there. 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 is when a boy 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 normally 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.
Also adults can experience problems with false beliefs. For instance, when they show hindsight bias,
defined as: "the inclination to see events that have already happened
as being more predictable than they were before they took place."
In an experiment by Fischhoff in 1975, 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 be unable to disregard certain
information that they have been given.
Unexpected contents
Other
tasks have been developed to try to solve the problems inherent in 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 (1988) found that children pass this test at age four or five years.
Other tasks
The "false-photograph" task
is another task that serves as a measure of 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 (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 the foregoing standards. One
category of tasks uses a preferential looking paradigm, with looking time
as the dependent variable. For instance, 9-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
Recent
research on the early precursors of theory of mind has looked at
innovative ways at capturing preverbal infants' understanding of other
people's mental states, including perception and beliefs. Using a
variety of experimental procedures, studies have shown 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 predicates on infants'
tendency to look longer at unexpected and surprising events compared to
familiar and expected events. Therefore, their looking-times measures
would give researchers an indication of what infants might be inferring,
or their implicit understanding of events. One recent 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 either searching
for a toy 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.
Deficits
The
theory of mind impairment describes a difficulty someone would have with
perspective-taking. This is also sometimes referred to as mind-blindness.
This means that individuals with a theory of mind impairment would have
a difficult time seeing 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, people with schizophrenia, people with nonverbal learning disorder, people with attention deficit disorder,
persons under the influence of alcohol and narcotics, sleep-deprived
persons, and persons 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 the
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 suggested 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 have been taken as a key feature of autism.
Many individuals classified as autistic have severe difficulty
assigning mental states to others, and they 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,
which suggests that with an autistic person, deficits in theory of mind
result from a distortion in understanding and responding to emotions.
He suggests that typically developing human beings, 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.
Tine et al. suggest 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 if 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.
Schizophrenia
Individuals with the diagnosis of 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 does not significantly affect the
performance of theory of mind tasks.
Current 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 would be able to accurately self-represent,
by comparing oneself with others and by viewing oneself from the
perspective of others.
Insight allows a patient to recognize and react appropriately to his
symptoms; however, a patient who lacks insight would 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.
The majority of the current literature supports the argument that
the 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. The results indicate
that the deficit is not merely a consequence of the active phase of
schizophrenia.
Schizophrenic patients' deficit in theory of mind impairs their
daily interactions with others. An example of a disrupted interaction is
one between a schizophrenic parent and a child. 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 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.
Although there is a strong association between theory of mind deficit
and parental role dysfunction, future studies could strengthen the
relationship by possibly establishing a causal role of theory of mind on
parenting abilities.
Alcohol use disorders
Impairments in theory of mind, as well as other social-cognitive deficits are commonly found in people suffering from alcoholism, due to the neurotoxic effects of alcohol on the brain, particularly the prefrontal cortex.
Depression and dysphoria
Individuals in a current 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. They 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 typically developing humans
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 has supported this view, demonstrating specific brain regions consistently engaged during theory of mind tasks. PET
research on theory of mind, using verbal and pictorial story
comprehension tasks, has identified 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.
Subsequently, research on the neural basis of theory of mind has
diversified, with separate lines of research focused 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 very consistently found activation in mPFC, precuneus, and
temporo-parietal junction (TPJ), right-lateralized. In particular, it has been proposed that the right TPJ (rTPJ) is selectively involved in representing the beliefs of others.
However, some debate exists, as some scientists have noted that the
same rTPJ region has been consistently activated during spatial
reorienting of visual attention; Jean Decety
from the University of Chicago and Jason Mitchell from Harvard have
thus proposed 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 6-10mm 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.
Functional imaging has also been used to study the detection of
mental state information in Heider-Simmel-esque animations of moving
geometric shapes, 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 has implicated 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 have 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
then apparently would demand more processing in the STS. Note that this
region is distinct from the temporo-parietal area activated during
false belief tasks.
Also note that 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 has provided support for neuroimaging results regarding the
neural basis of theory of mind. Studies with patients suffering from a
lesion of the frontal lobes and the temporoparietal junction of the brain (between the temporal lobe and parietal lobe) reported 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 (reviewed in) has shown that some sensorimotor neurons, which are referred to as mirror neurons, 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 carrying out the same task.
Similarly, fMRI
studies with human participants have shown brain regions (assumed to
contain mirror neurons) that are active when one person sees another
person's goal-directed action.
These data have 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 (see above).
There is also evidence against the 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 these 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 a recent paper, 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 potentially act to complement the function of mirror neurons during social interchange.
In autism
Several neuroimaging studies have looked at the neural basis 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 normal 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 no 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
no STS or FFA activation, and significantly 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 significantly less functional connectivity between STS and
V3 in the autism group. Note, however, that 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 doesn't reach STS. Both explanations
involve an impairment 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.
In 2011, 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, irrespective of 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 the 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 suggested as drivers of successful group performance. In particular, high group average scores on the RME are shown to be 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. A recent theory claims that Theory of
Mind has its roots in two defensive reactions, namely immobilization
stress and tonic immobility, which are implicated in the handling of
stressful encounters and also figure prominently in mammalian
childrearing practices (Tsoukalas, 2018).
Their combined effect seems capable of producing many of the hallmarks
of theory of mind, e.g., eye-contact, gaze-following, inhibitory control
and intentional attributions.
Non-human
An open question is whether other animals besides humans have a genetic endowment and social environment that allows them to acquire a theory of mind in the same way that human children do. This is a contentious issue because of the problem 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,
however, and 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 what many claim to be a
uniquely human aspect of social cognition. While it is difficult to
study human-like theory of mind and mental states in species 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 (or rather, 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.
Part of the difficulty in this line of research is that observed
phenomena can often be explained as simple stimulus-response learning,
as it is in the nature of any theorizers of mind to have to extrapolate
internal mental states from observable behavior. 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, and have shown 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. Two examples serve as demonstration: first, Povinelli et al. (1990)
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 (2001) 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 a 2016 experiment, ravens Corvus corax
were shown to take 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".
A 2016 study published by evolutionary anthropologist Christopher
Krupenye brings new light to the existence of Theory of Mind, and
particularly false beliefs, in non-human primates.
