RESEARCH INTO THEORY OF
MIND
In recent years, the phrase "theory of mind"
has more commonly been used to refer to a specific cognitive capacity:
the ability to attribute mental states—beliefs, intents, desires,
pretending, knowledge, etc.—to oneself and others and to understand
that others have beliefs, desires and intentions that are different
from one's own.[1]
General category usage of theory of mind
In functionalist theories, functionalists such
as Georges Rey explore computational theories of mind[2] that are
independent of the physical instantiation of any particular mind.In
brain-mind identity theories, biologists such as Gerald Edelman
are concerned with the details of how brain activity produces mind
and work within the confines of the identity theory of mind.[3]
Philosophical roots of Theory of Mind
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.[9]
The mental states attributed to others are unobservable—theoretical
notions that explain and predict behavior in the same way that doctors
interpret abnormal blotches on an x-ray as cancerous tumors—and
yet knowable by intuition or insight.
On the other hand, simulation theory suggests
Theory of Mind is not, at its core, theoretical. Two kinds of simulationism
have been proposed.[10] The first simulation theory suggests that
each person simulates being in another's shoes, extrapolating from
each one's own mental experience. The second kind of simulation
theory proposes that each person comes to know her own and others'
minds through what Gordon[11] names a logical "ascent routine"
which answers questions about mental states by re-phrasing the question
as a metaphysical one. For example, if Zoe asks Pam, "Do you
think that dog wants to play with you?", Pam would ask herself,
"Does that dog want to play with me?" to determine her
own response. She could equally well ask that to answer the question
of what Zoe might think.
One of the differences between the two theories
that have influenced psychological consideration of Theory of Mind
is that theory-theory describes Theory of Mind as a detached theoretical
process that is an innate feature, whereas simulation theory portrays
Theory of Mind as a kind of knowledge that allows one to mimic the
mental state of another person. These theories continue to inform
the definitions of theory of mind at the heart of scientific Theory
of Mind investigation.
Autism and theory of mind
There has also been speculation that certain humans
fail to progress through the normal cognitive developmental stages
that lead to acquisition of a theory of mind. In 1985 Simon Baron-Cohen,
Alan Leslie and Uta Frith published an article called "Does
the autistic child have a 'theory of mind'?" in which it was
suggested that children with autism have particular difficulties
with tasks requiring the child to understand another person's beliefs.
These difficulties persist when children are matched for verbal
skills (Happe, 1995, Child Development) and have been taken as a
key feature of autism.
Many autistic individuals have severe difficulty
assigning mental states to others, and they seem to lack theory
of mind capabilities.[25] 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.[26] According to Leslie,[27] 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 autistic individuals show extreme deficits in both theory
of mind and pretend play. However, Hobson proposes a social-affective
justification,[28] which suggests that an autistic person’s deficits
in theory of mind result from a distortion in understanding and
responding to emotions. He suggests that typically developing human
beings, unlike individuals with autism, are born with a set of skills
(such as social referencing ability) which will later enable them
to comprehend and react to other people’s feelings. Other scholars
emphasize that autism involves a specific developmental delay, so
that children with the impairment 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.[29]
Theory of mind development
Earlier in the twentieth century, Piaget articulated
a view with similarities to Theory of Mind: that in early childhood
egocentrism, a child does not understand that others’ views and
thoughts differ from his or her own.[12] There is now general agreement
among researchers that human children pass tests of theory of mind
much earlier than they leave Piaget's egocentric stage—by the age
of 3 or 4 years. There is considerable disagreement regarding which
behaviors necessarily indicate the presence of a developing theory
of mind in young (1- to 3-year-old) humans. Much research focuses
on investigating behaviors which may be precursors to the development
of a fully functional theory of mind. These behaviors include joint
attention, gaze following, proto-declarative pointing, comprehending
objects' animacy, and awareness of others as intentional agents.[13]
Gaze following—following another's gaze with one's
own—is seen in infants by about the age of six months, while markers
of joint attention, including shared mutual gaze, appear later,
around the age of 9-12 months. Additionally, behaviors such as proto-declarative
pointing—pointing in order to draw another's attention to an object
in the environment—also emerge around the end of the first year.[14]
This ability to engage in shared attention is considered to be crucial
for a child to learn about his or her social environment. A longitudinal
study conducted by Charman et al. (2000)[15] demonstrated that children
who displayed the highest rates of joint attention at 20 months
were generally the same children who scored highest on theory of
mind tasks at 44 months. Some researchers believe that these behaviors
and social referencing (using the emotional response of others to
determine one's own response to a novel object or situation) suggest
that children are beginning to have an awareness of adults' internal,
mental functioning.
An ability to distinguish between animate and
inanimate objects represents another step along the path toward
development of a theory of mind. In studies conducted to answer
the question of when people attribute animacy to objects, Tremoulet
and Feldman (2000)[16] demonstrated that objects that were perceived
to be most animate were those whose motion appeared to violate laws
of Newtonian physics or those moving objects that appeared to have
a goal. (Most normally developing humans will acquire the ability
to distinguish between animate and inanimate objects.)
After learning to define certain objects as animate,
children can then begin to develop the concept of other beings as
intentional "agents." An agent is an object that acts
in a goal-directed manner, essentially planning actions and then
carrying them out in the most efficient way possible in order to
attain some end. Using a habituation procedure, Gergely et al. (1995)[17]
found that 12-month-old children were able to demonstrate an understanding
that intentional agents act in rational ways. Meltzoff and Moore
(1999)[18] have shown that children as young as several hours or
days old may mimic simple behaviors, which may be part of a developing
Theory of Mind; other researchers have argued that 14- to 18-month-old
infants are capable of understanding intention and so have a basic
comprehension of others as intentional and mental agents.[19][20]
In a study of 18 month olds' ability to understand the intentions
of others, Meltzoff found that children mimic intentional, but not
unintentional, behaviors of (adult) humans in their environment,
and that they imitate considerably less often when a machine is
performing the behavior. This experiment suggests that infants younger
than two years of age may be considering the intentions of others
and interpret humans, and not machines, as intentional beings.
Empirical investigation of Theory of Mind
Whether children younger than 3 or 4 years old
may 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—(the German word Umwelt means "environment"
or "surrounding world")—of the pre-verbal child.
False-belief task
The canonical test of Theory of Mind ability is
the 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 wrong. 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).[21]
In the most common version of the false-belief
task (often called the ‘Sally-Anne’ task), children are told or
shown a story involving two characters. For example, in one version,
the child is shown two dolls, Sally and Anne, playing with a marble.
The dolls put away the marble in a box, and then Sally leaves. Anne
takes the marble out and plays with it again, and after she is done,
puts it away in a different 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 first box where
she put the marble; the child fails the task if she answers that
Sally will look in the second box, where the child knows the marble
is hidden, even though Sally cannot know, since she did not see
it hidden there. In order 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.
The false-belief task has, in a number of studies,
been modified so as to make certain that children who fail the tasks
do so because they lack the Theory of Mind ability required, and
not because the tasks are too cognitively demanding for them. Low-verbal
false-belief tasks have tried to eliminate the possibility that
the language of the task is too complicated for young or language-delayed
children to understand. Such tasks often employ thought bubbles
rather than explicit words to show a character thinking. The results
of research using false-belief tasks have been fairly consistent:
most normally-developing children are unable to pass the tasks until
around the age of three or four. The conclusion from this research
has thus been that most children do not begin to have any mature
theory of mind abilities until this time. Passing these tasks does
not necessarily mean that a child has a theory of mind like that
of an adult—in fact, studies with mental verb acquisition show that
at the age when children can pass the false-belief task, they still
have difficulty in understanding differences between mental states—but
being able to pass them is an indication that a child has developed
the kinds of understanding, like false-belief, necessary for gaining
adult Theory of Mind abilities, and that they are on their way to
an adult Theory of Mind. Inability to pass the false-belief task–and
thus the apparent inability to understand false belief–at an age
when one is expected to be able to do so is usually taken as an
indication of a developmental delay or other disruption that has
affected Theory of Mind development.
Appearance-reality task
Other tasks have been developed to try to solve
the problems inherent in the false-belief task. In the "appearance-reality",
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," each 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 she responds that another person will think that there are
"Smarties" 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[22][23]
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, there is either a location or identity
change.[24] In the location-change task, the child is told a story
about a character that puts an object in one location (e.g., chocolate
in a green cupboard) and takes a Polaroid photograph of the scene.
While the photograph is developing, the object is moved to a different
location (e.g., to a blue cupboard). The child is then asked two
control questions, “When we first took the picture, where was the
object? 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 she correctly identifies the location of the object
in the picture and the actual location of the object at the time
of the question.
In order to make tasks more accessible for young
children, non-human animals, and autistic individuals, theory of
mind research has begun employing non-verbal paradigms. One category
of tasks uses a preferential looking paradigm, with looking time
as the dependent variable. For instance, Woodward found that 9-month-old
infants preferred to look at behaviors performed by a human hand
than those made by an inanimate hand-like object.
Theory of mind in the brain
With the advent of neuroimaging techniques, particular
brain regions that seem to be important for theory of mind have
been identified by researchers including Chris Frith[30] and Rebecca
Saxe.[31] These studies identify the medial frontal cortex, temporal
poles and temporoparietal junction as the brain regions which are
most active when people perform theory of mind tasks.
A paper published in 2004 by Samson and colleagues
in Nature Neuroscience [32] shows that people who have a stroke
which damages the temporoparietal junction of the brain (between
the temporal lobe and parietal lobe have difficulty with some theory
of mind tasks. This shows that theory of mind abilities are associated
with specific parts of the human brain.
Mirror Neurons
Recent research by Vittorio Gallese and Giacomo
Rizzolatti (reviewed in [33]) has shown that some visuomotor neurons,
which are referred to as mirror neurons, first discovered in the
premotor cortex of rhesus monkeys, may be involved in theory of
mind abilities. Single-electrode recording revealed that these neurons
fired when a monkey performed an action and when the monkey viewed
another agent carrying out the same task. Similarly, fMRI studies
with human participants have shown brain regions which are assumed
to contain mirror neurons are active when one person sees another
person's goal directed action.[34] These data have been used to
suggest that mirror neurons provide the basis for theory of mind
in the brain, and to support Simulation Theory (see above) [35]
However, 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. Second, fMRI studies of theory of
mind typically activate the medial frontal cortex, temporal poles
and temporoparietal junction,[36] but these brain areas are not
part of the human mirror neuron system. Some investigators believe
that mirror neurons merely facilitate learning through imitation
and may provide a precursor to the development of Theory of Mind.
Non-human theory of mind
As the title of Premack and Woodruff's 1978 article
"Does the chimpanzee have a theory of mind?" indicates,
it is also important to ask if 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, of the existence of a concept
of self or self-awareness, or of particular thoughts.
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 which we do not yet describe as "minded" at
all, and about 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). 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.
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)[37] presented chimpanzees with the choice of two experimenters
from which 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)[38] found that subordinate chimpanzees were
able to use the knowledge state of dominant rival chimpanzees to
determine which container of hidden food they approached.
Tomasello and like-minded colleagues who originally
argued that great apes did not have theory of mind have since reversed
their position. Povinelli and his colleagues, however, maintain
that Tomasello's group has misinterpreted the results of their experiments.
They point out that most evidence in support of great ape theory
of mind involves naturalistic settings to which the apes may have
already adapted through past learning. Their "reinterpretation
hypothesis" explains away all current evidence supporting attribution
of mental states to others in chimpanzees as merely evidence of
risk-based learning; that is, the chimpanzees learn through experience
that certain behaviors in other chimpanzees have a probability of
leading to certain responses, without necessarily attributing knowledge
or other intentional states to those other chimpanzees. They therefore
propose testing theory of mind abilities in great apes in novel,
and not naturalistic settings. Kristin Andrews takes the reinterpretation
hypothesis one step further, arguing that it implies that even the
well-known false-belief test used to test children's theory of mind
is susceptible to being interpreted as a result of learning.
References and notes
1 Premack, D. G. & Woodruff, G. (1978). Does
the chimpanzee have a theory of mind? Behavioral and Brain Sciences,
1, 515-526.
2"The Computational Theory of Mind" - Stanford Encyclopedia
of Philosophy
3"Identity theory of mind" - Stanford Encyclopedia of
Philosophy
4 Premack, D. G. & Woodruff, G. (1978). Does the chimpanzee
have a theory of mind? Behavioral and Brain Sciences, 1, 515-526.
5 Courtin, C. (2000) The impact of sign language on the cognitive
development of deaf children: The case of theories of mind. Cognition,
77,25-31.
6 Courtin, C., & Melot, A.-M. (2005) Metacognitive development
of deaf children: Lessons from the appearance-reality and false
belief tasks. Journal of Deaf Studies and Deaf Education, 5, 266-276.
7 Premack, D. G. and Woodruff, G. (1978). Does the chimpanzee have
a theory of mind? Behavioral and Brain Sciences, 1, 515-526.
8 Premack, D. G. and Woodruff, G. (1978). Does the chimpanzee have
a theory of mind? Behavioral and Brain Sciences, 1, 515-526.
9 Carruthers, P. (1996). Simulation and self-knowledge: a defence
of the theory-theory. In P. Carruthers & P.K. Smith, Eds. Theories
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10 Gordon, R.M. (1996). 'Radical' simulationism. In P. Carruthers
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11 Gordon, R.M. (1996). 'Radical' simulationism. In P. Carruthers
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12 Piaget, J., & Inhelder, B. (1948/1967). The Child's Conception
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13 Terje Falck-Ytter, Gustaf Gredebäck & Claes von Hofsten,
Infants predict other people's action goals, Nature Neuroscience
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26 Leslie, A. M. (1991). Theory of mind impairment in autism. In
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27 Leslie, A. M. (1991). Theory of mind impairment in autism. In
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31 http://arjournals.annualreviews.org/doi/abs/10.1146%2Fannurev.psych.55.090902.142044
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34 Iacoboni, M., Molnar-Szakacs, I., Gallese, V., Buccino, G., Mazziotta,
J.C. (2005). Grasping the intentions of others with one's own mirror
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35 Gallese, V., & Goldman, A. (1998). Mirror neurons and the
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Excerpts taken from: Davis, E. (2007) Mental Verbs in Nicaraguan
Sign Language and the Role of Language in Theory of Mind. Undergraduate
senior thesis, Barnard College, Columbia University.
Students of the Spring 2007 course Theory of Mind and Intentionality
at Barnard College (Columbia University) contributed extensively
to this page.
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