Theory of Mind Hypothesis: Explaining Autism
2002, Satyan Chari,
B.O.T., G.C.Occ Thy, Msc. Occ.Thy., University of Queensland
People with autism sometimes have difficulty comprehending when
others do not know something. Autistic individuals can become extremely
agitated when another person does not know the answer to a question
they ask. By not understanding that other people think differently
than themselves, many autistic individuals may have problems relating
socially and communicating to other people. That is, they may not
be able to anticipate what others will say or do in various situations.
In addition, they may have difficulty understanding that their peers
or classmates even have thoughts and emotions, and may therefore
appear to be self-centered, or uncaring.
term theory of mind was coined by Premack and Woodruff,
1978 and is often used to refer to the ability to attribute
mental states and to use these invisible postulates to explain behaviour
in everyday life. Premack and Woodruff defined theory of mind as
the ability to ascribe mental states to oneself and to others. The
ability to ascribe these mental states was called a theory
because mental states are not observable. Premack and Woodruff also
used the term theory as mental constructs of states
of mind are used to predict behaviour.
theory of mind concept was actually first proposed in research exploring
primate psychology and primate social organisation. The concept
was initially used to explain observations where the chimpanzees
demonstrated behaviours that required them to know what another
chimpanzee may be thinking, or was possibly about to do, in response
to an occurrence in its environment. The ability to ascribe mental
states to other chimpanzees was called a theory of mind
(ToM). This concept was subsequently identified by researchers in
the field of autism as a possible absent ability that may be resulting
in some of the manifest behaviours seen in children with autism.
The definition of what a theory of mind has however,
changed as research has progressed and has different shades of meaning
across different areas of research.
The Theory of Mind Hypothesis in Autism
definition of autism at a biological level continues to remain elusive.
But a fairly clear idea is emerging of a cause at a cognitive level.
Specific discrete behavioural deficits are seen in autism such as
impaired social functioning, impaired communication and lack of
imaginative play. In fact, the triad of social impairment, reduced
communication and decreased imagination characterizes the whole
spectrum of autistic disorders (Wing, 1986). Baron-Cohen, Leslie
and Frith (1988) suggested that this association between these three
areas of functioning could be explained by a single cognitive deficit,
that is, an inability to cognitively represent mental states, otherwise
called a theory of mind. Representing mental states such as belief
and desire is required to predict other peoples behaviour.
Morton and Leslie, (1991) described the difference between normal
and autistic children as in a normally developing child,
the computational capacity to represent mental states has an innate
neurological basis. In the autistic child damage to the circumscribed
system of the brain has occurred, and this prevents the normal operation
of the critical cognitive mechanism. The ability to represent
mental states would appear to be crucial for normal reciprocal social
interaction, for understanding a speakers intended meaning
in communication, and for understanding contrast between real and
imaginary events. Wimmer and Perner (1983) designed the first false
belief tasks to test the hypothesis. The test required the ability
to attribute a false belief to another person (Sally Ann
task). Wimmer and Perner found that almost all children over the
age of 4 years passed the task. In contrast, Baron-Cohen, Leslie
and Frith (1988) found that only 20% of a sample of autistic children
were able to pass this task despite having mental ages over 4 years.
It is interesting to note that in the same study, 85% of a sample
of children with Downs Syndrome passed the test even though
they had significantly lower verbal ability than the age-matched
group of children with autism. Subsequent studies have confirmed
that a large proportion of children with autism have great difficulty
in tests designed to tap into Theory of Mind ability.
of Theory of Mind
orders of theory of mind ability have been described in literature
(Baron-Cohen, 1995). First-order ToM refers to inferring the thoughts
of another person; an example of this could be a child (X) knowing
what his friend (Y) might be going through after losing his favourite
toy. Normal children pass first-order tests of ToM by the age of
four years. Second-order ToM refers to reasoning, that is, what
one person (other than the self) thinks about another person's thoughts.
Extending the same example, this would refer possibly to a third
child watching the two children and reasoning what child X would
be thinking about child Y.
functions in the Theory of Mind and Asperger's Syndrome
and adults with Aspergers Syndrome have also been shown to
suffer from deficits in ToM though they are more likely to pass
tests of ToM relative to the performance of children and adults
with autism (Baron-Cohen, 1995). Since many children and adults
with Asperger's disorder do pass second-order ToM tasks, such tasks
cannot be interpreted as conclusive evidence of intact ToM. However,
a persons performance on such tasks does provide evidence
for the level of impairment.
those who do pass such tasks due to a high level of functioning,
more advanced tasks can measure ability to read nonverbal cues such
as facial and eye expressions. As a group, children and adults with
Autism or Asperger's disorder are less able to interpret nonverbal
language and cues than normal persons are. We often use facial expressions
to determine what a person may be thinking or what message he/she
may be giving us. A deficit in this ability puts anyone at a major
disadvantage in almost every situation, especially at social situations
when a person is required to interpret such cues from multiple persons
simultaneously. These cues let us know when it is all right to interrupt,
when others are interested in what we are saying, when to stop talking,
when others are lost by tangential conversation, etc. Without this
ability, a person is likely to feel overwhelmed in such situations
and may prefer to retreat from others.
causes of Theory of mind impairments
biological causes of autism vary greatly. It is three to four times
more frequent in male children. This, along with the fact that increased
concordance rates are noted in monozygotic twins points towards
a probable genetic association. There has been a lot of research
done on people with autism in the past two decades to identify the
affects autism has on the brain. Every lobe of the brain, with the
exception of the occipital lobe has been implicated in the pathophysiology
of autism. However, specific brain regions seem to be more involved
in studies where subjects were tested on theory of mind tasks.
studies of normal subjects engaged in tasks designed to tap into
the theory of mind have shown increased activation of a range of
frontal regions. Individuals with frontal lobe lesions have also
shown to display abnormalities of social and emotional functioning
(Saver and Damasio, 1991). Adults with right hemisphere damage appear
to have social and communicative deficits that resemble those seen
in high-functioning individuals with autism (Happe, Brownell and
Baron-Cohen, Ring, Moriarty, Schmitz and Costa (1994) and Fletcher,
Happe, Frith, Baker, Dolan, Frackowiak, and Frith (1995) found frontal
brain regions to be specifically more active during theory of mind
tasks than during control tasks but there is relatively little agreement
on the exact sub-regions involved. In the study by Baron-Cohen et.
al. (1994), increased activation was noted in the right orbito-frontal
regions. Fletcher et al. (1995) used stories requiring mental state
attribution, a skill difficult for even high-function autistic children
and found through PET imaging that left medial frontal regions were
significantly more active during the task.
Happe, Brunswick, Fletcher, Frith and Frith (2000) found activity
increases in the medial frontal and paracingulate regions through
MRI studies. They also identified increased activity in the temporal-parietal
junction and temporal poles bilaterally when subjects were engaged
in theory of mind tasks.
a study by Happe, Brownell and Winner (1999), left hemisphere damaged
patients showed no evidence of ToM impairments, but it needs to
be noted that none of these patients had lesions to the key frontal
areas implicated in imaging studies of theory of mind.
While left frontal regions may play a key role in the neural circuits
underlying ToM, the most probable explanation would indicate a neural
circuit that has important centres in other regions of the brain
(primarily in the right frontal lobe) which would cause similar
deficits if affected.
Theoretical Models explaining Theory of Mind Deficits:
from brain imaging studies and the peculiar association between
specific deficits in children with autism, has provided researchers
with information to build models to explain theory of mind deficits.
Current models that attempt to explain the theory of mind concept
(and impairments in it) can be organized into two distinct categories.
One group of models is based on the theory of modularity proposed
by Fodor (1983), the second group of models can be classified as
in favour of a dedicated cognitive mechanism, or module, underlying
The theory of mind have pointed to evidence of dissociation in developmental
disorders. Theory of mind ability appears to be dissociable from
cognitive ability in other domains. For example, children with autism
may lack a theory of mind but may be intelligent in other respects
(Baron-Cohen, Tager-Flusberg, Cohen, 1993), and children with Williams
syndrome, can show intact theory of mind despite delayed mental
development in other domains (Karmiloff-Smith, Klima, Bellugi, Grant
and Baron-Cohen 1995).
Brothers Social Brain Theory
Ring and Kling (1990) suggested proposed that social intelligence
should be differentiated from other kinds of intelligence (hence
a modular theory). He suggested that social intelligence might have
its own neural circuitry (amygdala, orbitofrontal cortex and superior
temporal sulcus). He proposed that these neural structures together
could be called the social brain. Studies on selective
social impairments seen in brain damaged patients provided considerable
evidence for this theory.
Leslies Modularity Theory
Leslie (1991) suggests that a specific area in the brain that is
selectively responsible for understanding and interpreting mental
states is present in normal cases and impaired in individuals with
autism. He coined the term Theory of Mind Mechanism
to describe what he considers to be a module responsible
for this function.
Baron-Cohens Innate Minimalist Modularity Theory
(1995) proposed a theoretical model (based on his background in
evolutionary biology and developmental psychology) that consisted
of four discrete sub-systems or mechanisms, which together comprise
the human mind-reading system. The first mechanism is
the Intentionality Detector (ID). The ID is proposed
to be a perceptual device that interprets primitive volitional
mental states such as goal and desire (want). These are seen as
basic mental states required for making basic sense of the movements
of all organisms in the environment. For example, an infant seeing
an adult move across the room would (through the ID mechanism) interpret
that as the adult wants to go there or the adult
does not want to stay here. The ID is considered to be an
innate mechanism that infants possess for reading mental states.
second innate mechanism is the Eye Direction Detector (EDD). Baron-Cohen
suggests that the EDD has three basic functions of detecting the
presence of eye-like stimuli, computing whether eyes are directed
towards it or towards another direction and inferring from the observation
that the organisms eyes are directed at something else that
it actually sees something. In simpler words, the third function
interprets gaze as seeing. The last function is considered
especially important to mind-reading as it allows the infant to
attribute a specific perceptual state to the organism (the
monkey sees the banana or mummy sees me). Both
these mechanisms allow the infant to interpret observed behaviour
as a small number of mental states. Another defining similarity
between these two mechanisms is that they allow the infant to interpret
behaviour on a dyadic level, that is, between the organism/agent
and the infant or the organism/agent and the object it sees. This
is considered by Baron-Cohen to be suggestive of the autistic
third mechanism is the Shared Attention Mechanism (SAM). The SAM
is considered to be a higher order skill that allows the individual
to form what is called triadic representation. Triadic
representations conceptualize relations between an Agent, the Self
and an Object (which can be another agent). The SAM builds triadic
representations by perceiving the perceptual state of another agent
and computes shared attention by comparing another agents
perceptual state with the selfs current perceptual state.
The last mechanism described is the Theory of Mind Mechanism (ToMM).
The ToMM is considered to be a system for inferring the complete
range of mental states observed from human and animal behaviour.
The ToMM achieves this by representing the set of epistemic mental
states (imagining, dreaming, knowing, deceiving, believing etc.)
and combining the different mental state concepts (volitional, perceptual
and epistemic) in to a rational understanding of how mental states
relate to actions and each other.
Johnson and Mortons Minimalist Innate Modularity Theory
modularity theory proposed by Johnson and Morton (1991) is a truly
minimalist theory. The authors of this theory postulate that only
two innate mechanisms are involved in the steps leading to acquisition
of a theory of mind. The first mechanism is termed CONSPEC which
takes hold of the infants attention to look at a face-like stimuli
and CONLERN which directs the infants attentional system to
learn about faces. Therefore according to this theory, mechanisms
such as ID, EDD and ToMM would in turn be acquired modules.
General Learning Mechanism Theory
the argument of minimalism to an even more simplistic level, Baron-Cohen
(1998) proposes a general learning mechanism theory, which encapsulates
the view held by certain learning theorists. This theory argues
that there is nothing innate in cognition and that everything learnt
from the environment. There are fundamental deficits in this kind
of a model in that it cannot account for certain kinds of conditions.
An example of this would be a case of a person with Aspergers
syndrome who have good general intelligence but have difficulties
in the social domain. This would contradict a singular all-encompassing
learning theory as good general intelligence would indicate a good
general learning mechanism and could not therefore explain social
Fish out of Water Theory
'fish out of water' theory is that children with autism have failed
to develop mammalian behavioural response patterns, so they have
to rely on an earlier system of orientations. Griffin, J., (1999)
advanced this theory based on certain phylogenetic observations
of fetal development, and stress-responses of normal infants and
children with autism. He proposed that the ontogenetic mirroring
that is seen in human development may include certain mechanisms
in cognitive development. A lack of appropriate mammalian
responses could be attributed to a developmental deficit according
to this theory. The research support for this theory is however,
theory of mind hypothesis is increasingly being recognised as an
explanatory cause for a large majority of deficits seen in Autism
Spectrum Disorders. Theory of mind refers to the notion that many
autistic individuals do not understand that other people have their
own plans, thoughts, and points of view. Furthermore, it appears
that they have difficulty understanding other people's beliefs,
attitudes, and emotions.
of the tasks used to test this theory have been given to non-autistic
children as well as children with mental retardation, and the theory
of mind phenomenon appears to be unique to those with autism. Acquired
theory of mind deficits are also seen in patients with brain injuries,
those who have undergone neuro-surgical procedures, schizophrenia
and Williams syndrome. Evidence is growing that there might
be dedicated neural circuitry that involves a number of areas in
the right frontal lobe, certain portions of the left orbitofrontal
cortex and amygdala that is responsible for theory of mind abilities
among other functions. Current theories are evolving into constructs
that are still relatively modular in nature but with less apparent
delineation of functions. However, a purely neurolobiological explanation
will not be able to completely explain the deficits seen in theory
of mind abilities as autism has definite genetic and biochemical
clinical implications of recent findings about theory of mind deficits
are large. An understanding of the specific mechanisms underlying
the manifest behaviour in children with autism will help clinicians
devise different levels to intervene on. For example, a large number
of available interventions in dealing with communication in children
having autism focus on end-product abilities (PECS, Makaton etc.).
Social skills training programs also aim at teaching children with
autism appropriate skills that would help them respond in an adaptive
way when functioning in social settings. These skills, although
beneficial, will not be easy to generalise for an individual with
autism as he/she would lack the insight into the theory of
mind of others around him/her. Therefore the only alternative
available for autistic individuals would be to memorise a large
enough repertoire of interactional skills such that he/she would
be prepared for most social eventualities. The easier and more effective
option would be to train individuals with autism to develop even
a basic insight into theory of mind concepts. However, there is
very little literature documenting the use of such programs and
there is even less literature documenting the efficacy of and methods
that can be utilised.
From a clinical perspective, theoretical evidence is sufficient
in support for the theory of mind model to start developing
and testing specific interventions based on it. Many standardised
and reliable variations of false-belief task tests and mental state
attribution tests are currently available. These tests can be incorporated
in to clinical studies on theory of mind interventions to provide
significantly objective results.
social interaction, the ability to understand other peoples
beliefs, motivations, and goals is crucial. Mentalizing
(Frith and Frith, 1999) or Theory of Mind (Premack and Woodruff,
1978), is at the core of successful interaction with other human
beings. Theory of Mind (ToM) is necessary for understanding and
predicting other peoples behavior and, in turn, for reacting
adaptively to the changing environment. There is a large body of
knowledge about the development of this ability in childhood (Wellman,
1993), and it has been shown that autistic children have specific
deficits in ToM processing (Baron-Cohen, Leslie and Frith 1985).
Recently, a number of neuropsychological patient studies and neuroimaging
studies have attempted to further understand the neuroanatomical
basis of ToM abilities. Cortical regions shown to be particularly
important for ToM processes are the frontomedian cortex and the
amygdala. Increased understanding has brought research to a point
where theoretical evidence can be translated into specific interventions.
In terms of a clinical perspective, future research should aim at
designing appropriate intervention programs for children with autism
based on the theory of mind model.
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