Emerging Trends in The Social and Behavioral Sciences

Theory of Mind

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Theory of Mind

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Theory of Mind
HENRY WELLMAN

Abstract
Humans are a social species. We not only live socially, but also think socially, accumulating myriad thoughts and knowledge about our social world. A hallmark of
this human social cognition is an everyday theory of mind––our ordinary human
understanding that persons (self and others) have internal mental states––desires,
beliefs, feelings, hopes—that crucially shape their actions and lives. I review classic
and current knowledge on the nature and importance of theory of mind. Theory of
mind is achieved and changes over human development; so, I emphasize that we
must understand its development. Fortunately, development of this everyday theory of mind is an intriguing story in its own right, and a great portion of the research
on theory of mind is developmental research with typical and atypical infants and
children.

In March 2007, NBCNews.com posted an article headlined “Mindreading
Scientists Predict Behavior.” At a lab in Germany, volunteers in an MRI
machine performed simple tasks of deciding whether to add or subtract
two numbers that they would see a few seconds later. Researchers tried to
read these volunteers’ minds from their brain scans, by judging what the
person intended, in their thoughts before they acted. The researchers, led
by Dr. Haynes in Berlin, were reasonably successful—about 70% accurate
at identifying the subjects’ decisions about whether they would add versus
subtract the two numbers. That made them about 20% more successful than
random guessing. The article cited various enthusiastic reactions and even
ended by noting that some commentators and ethicists are alarmed by the
implications of such mind reading.
Mind reading is indeed amazing. Yet actually, even 2-year olds and
3-year-olds do this sort of thing every day; even infants can succeed at
figuring out someone’s intentions. They succeed not with fancy machines,
but with their fancy 2-year-old brains and their ordinary, still-developing
theory of mind. We all “read minds” in this ordinary (mundane but fully
amazing) way. And we are better than these scientists—not infallible (but
Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

often better than 70% for simple things like inferring intentions and then
using them to predict behavior) and we are also able to do so in much less
constrained everyday situations. How we do this is the story of theory of
mind (and a great deal of research).
Theory of mind describes our wide-ranging human understanding of
agents’ mental states, such as intentions, desires, and thoughts, and how
action is shaped by such states. It refers to our everyday psychology, appropriately emphasizing the “mind reading” that so strongly characterizes our
everyday, commonsense understandings. Consider Romeo and Juliet. We
easily understand that Romeo loves Juliet and wants to be with her. But he
thinks his parents (and his clansmen) will violently object, so he tries to meet
with her in secret.
Philosophers and psychologists often characterize our everyday theory of
mind as a belief–desire psychology. Such an everyday psychology provides
explanations and predictions of action by appeal to what the person thinks,
knows, and expects, coupled with what he or she wants, intends, and hopes
for. Why did Romeo meet Juliet secretively: He wanted to be with her, and
thought his kinsmen would interfere. Everyday psychological reasoning also
includes reasoning about the origins of mental states (Romeo wants to be
with Juliet because he loves her; he thinks his kinsmen will violently object
because he has seen their violence in the past). That is, beyond beliefs and
desires, theory of mind incorporates a variety of related constructs such as
drives and preferences that ground one’s desires, and perceptual–historical
experiences that ground one’s beliefs. It also includes emotional reactions
that result from these desires, beliefs, preferences, and perceptions: happiness at fulfilled desires, frustration at unfulfilled desires, surprise when
events contradict one’s firmly held beliefs.
Acquisition of this everyday theory of mind may be one of the most
impressive intellectual accomplishments of human development. Much
like human language, theory of mind is notably abstract, but accomplished
in basic forms rapidly by young children everywhere. And, again like
language, both intriguing early competences and striking developments are
readily apparent: Infants closely attend to other humans; 2-year-olds talk
about persons’ wants and feelings and comfort others in distress; 3-year-olds
and 4-year-olds talk about thoughts and begin to engage in lies and trickery;
and nuanced theories of mind—in adults’ “folk psychologies”—are apparent
in (and dramatically differ across) cultural communities worldwide. Indeed,
revealing developmental data showing near-universal attribution by young
children of mental states to self and others has helped fuel rampant contemporary interest in theory of mind. Lay adults and children are embedded
in theory of mind; scientists, scholars, and the newsreading public are now
immersed in it.

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FOUNDATIONAL RESEARCH
Think about Romeo and Juliet again. Theirs is a story about love and desire,
but love and desire gone awry. At the end of the play, down in the crypt,
Romeo still desires Juliet who is alive and well right beside him, but he kills
himself. Why? Because, he believes she is dead. Understanding the possibility
of an internal realm of mental representations (ideas, thoughts, images) is
a hallmark of theory of mind. Understanding false beliefs (FBs), when contents of the world (Juliet is alive) contradict the contents of thought (“Juliet
is dead”), provides a powerful illustration of such everyday understanding.
This is one reason why there has been so much research on children’s
understanding of FBs (hundreds of studies and thousands of children
encompassed in several meta-analyses, e.g., Milligan & colleagues, 2007;
Wellman & colleagues, 2001). Another reason for this voluminous research
is that when researchers were first becoming interested in theory of mind,
several easy-to-use, “standard” false-belief tasks were developed of the
sort depicted in Box 1. And these have proved nicely revealing. For one,
they consistently show an important developmental transition. Indeed, as
graphed in Box 1, because they have been used worldwide, false-belief tasks
reveal a universal childhood theory-of-mind developmental achievement.
Worldwide, children go from consistent false-belief errors to consistently
correct understanding of FBs during early childhood. The timing of coming
to understand FBs can also differ intriguingly across countries.

Box 1

FB tasks have children (or adults) reason about an agent whose actions should be controlled by an FB. Such tasks have many forms, but a common task employs a change in
locations, as depicted above. The child (not shown above) sees the character, Jill, puts
her candy in the drawer. Jill leaves and, while she cannot see, the candy gets moved to
the cupboard. Jill returns, wants her candy, and the child is asked “Where will Jill look
for her candy?” or “Where does Jill think her candy is?” Older children answer correctly, like adults. Younger children answer incorrectly; they are not just random they
consistently say Jill will search in the cupboard (where it really is). Note that the task
taps more than just attribution of ignorance (Jill doesn’t know) rather attribution of FB
(Jill thinks—falsely—her candy is in the drawer).

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Country
5
4
Proportion correct (logit)

Australia
3
2

Austria
Canada
Japan

1
0

USA

−1
−2

Hong Kong

−3
−4
−5

England
30

40

50

60

70

80

90

100 110

Age (months)
(Data from Wellman and colleagues
2001; Liu and colleagues 2008.)

A frequently used alternative task uses deceptive contents (rather than change of location). For example, children see a crayon box, say they think it holds crayons, then upon
opening see it holds candies. They are asked what someone else who has never looked
inside will think the box holds—crayons or candies.
Several factors make such tasks harder or easier, but nonetheless children go from consistently below -chance to above-chance performance, typically in the preschool years.
Moreover, as shown in the graph at left, children in different cultural-linguistic communities can achieve FB understanding somewhat more quickly or more slowly, yet
in all locales they evidence the same trajectory—from below-chance to above-chance
performance in early to middle childhood. This is true even for children growing up
in non-western cultural communities speaking non-Indo-European languages. And is
true even for children in traditional, nonliterate societies.

There is more to say about FBs, but a focus on a single task or achievement
is limited and misleading. So, importantly, other research shows that by 4–6
years, children not only expect people to act in accord with their beliefs but
also explain persons’ actions by citing their mental states, including their
beliefs; they also come to understand about lies and deception, appearances
versus reality, that someone’s external expressions need not display their
internal emotions, and more. As a single intriguing example, 3-year-old
and 4-year-old children explicitly judge that a person’s ideas, thoughts, and
dreams are “internal,” immaterial, private experiences in contrast to real,
concrete, overt physical events (Harris & colleagues, 2006; Wellman & Estes,
1986).

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SOCIAL ACTION
Children’s development of this network of belief–desire reasoning dramatically impacts their actions and interactions with others. One way to
appreciate this is to note that amid the consistent trajectories shown in Box 1,
there is also obvious variation. Although almost all normally developing
children eventually master FBs, some children (not only across countries, but
also within any cultural–language community) come to this understanding
somewhat earlier and some later. This variation has been important for
identifying outcomes that are influenced by theory-of-mind understandings.
Indeed, differences in FB understanding, as measured in the preschool years,
predict several key childhood competences, such as how and how much
children talk about people in everyday conversation, their engagement
in pretense, their social interactional skills, and consequently their interactions and popularity with peers. Preschool variation in theory-of-mind
understanding also influences children’s use of deception, their strategies
for arguing with and persuading others, and their actions in games like
Hide-and-Seek. These findings reveal and confirm theory of mind’s real-life
relevance. (See Wellman, 2014, Chapter 3, for a review.)
AUTISM
What would social understanding and social interaction be like for someone
with an impaired theory of mind? A long-standing proposal is that individuals with autism might approximate such a case—the “theory-of-mind
hypothesis for autism.” Indeed, in classic studies, school-age children and
adolescents with autism were given standard false-belief tasks much like
the one depicted in Box 1. Although the tasks were largely nonverbal (and
children could respond merely by pointing), and although individuals with
autism were correct on all the related control questions, they were consistently incorrect on the false-belief judgments themselves. In comparison, not
only are younger typically developing 4-, 5-, and 6-year-olds consistently correct, older children with Down’s Syndrome, matched in age to those with
autism, are also consistently correct (Baron-Cohen, 1995).
The consensus perspective on theory of mind is that it targets a special
sort of reasoning about the social domain of agents’ actions and minds.
But, perhaps, theory of mind is really just a straightforward manifestation
of more domain-general cognitive processes such as memory, inference,
and executive functioning. And, similarly, perhaps those are the critical
deficits for autism, not something more specially social–cognitive. In this
regard, high-functioning autistics’ performance with false photographs
versus FBs has proved revealing. False-belief tasks are outlined in Box 1;
false-photograph tasks are comparable in format, but target not mental

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representations that are outdated and so false but rather outdated photos
that no longer match what is so. High-functioning autistics that consistently fail false-belief tasks consistently pass parallel false-photo tasks
(Leekam & Perner, 1991; Leslie & Thaiss, 1992). Because these individuals’
memory, attention, learning, and executive functioning are sufficient to
understand false photos, such domain-general processing factors fail to
account for their parallel difficulties with FBs. Data such as these help
confirm that theory of mind is a specialized and distinctive form of social
understanding.
At the same time, it is important to note that almost no researchers or clinicians today argue that autism deficits are solely characterized or caused by
theory-of-mind deficits.
INFANCY
Classically, theory-of-mind research began with older children, such as
preschoolers, and moved backward. It is now clear that understanding of
people in terms of their internal, psychological states begins in infancy.
The earliest examples of psychological construals of persons appear in
intention understandings; by the end of the first year, children begin to treat
themselves and others as intentional agents. Box 2 presents an example of
just one method used to demonstrate intention understanding in infants
(from Brandone & Wellman, 2009). In the initial demonstrations, using something like this paradigm, infants saw an animated circle “jumping” over a
barrier to reach its goal object. Just as they do for intentional human acts
like reaching, 9- and 12-month-olds look longer at the animated indirect test
events over the direct ones, showing an abstract, generalized understanding
of intentional agency (Gergley & colleagues, 1995).
Infant understandings of intentional action appear not only in looking-time
research but also in more active–interactive paradigms. A classic study of
this type went beyond examining infant understanding of successful actions
(e.g., a reach that successfully retrieves an object, as in Box 2) to consider
understanding of failed actions (Meltzoff, 1995). Arguably, inferring a goal
when it is unfulfilled, and thus nonovert in the actor’s movements or
outcomes, demonstrates a still deeper understanding that intentions exist
beneath the surface of performed actions. So, in this study, 18-month-olds
witnessed an adult try but fail to fulfill several novel, object-directed goals
(e.g., trying to hang a ring on a hook). Although infants never saw the actions
successfully modeled, when given a chance to act on the objects themselves,
they “imitated” the successful action much more than the failed (actually

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witnessed) actions. So, they understood the action’s goal even when it was
never observed.

Box 2

Habituation event

Direct reach test event

Indirect reach test event

Habituation-test (or familiarization-test) looking-time paradigms set the infant up so
that he or she will then look longer at novel, unexpected test events. In the reaching
paradigm (above), infants view multiple trials of the barrier-reaching event in habituation. Then, the barrier is removed and the test events contrast two different construals of
the person’s actions, one in terms of intentions and one in terms of physical motions of
the body. Suppose during habituation the infant construes the actor’s action in terms of
its physical movement (the arm and hand up and then down in an arc), then the indirect reach test event should be expected (as it repeats the same movement), whereas
the direct reach will stand out as novel and so specially attention-worthy. In contrast,
if the infant initially construes the action as goal directed, then when the barrier is
removed the direct reach is the expected action because there the actor continues to
directly seek the goal. Under this second construal, the indirect reach would be more
attention-worthy because (although the actor’s arm movement remains the same as during habituation) the actor no longer seems straightforwardly directed to the goal. Infants
who are 8, 9, 10, and 12 months old consistently look longer at the indirect test event.
Infants look equally to both test events in control conditions where they are first habituated to a display with no barrier or first habituated to the exact same over-the-barrier
arm movements but where there is no goal-object.

Key infant understandings encompass their understanding of intentional
action and internal experience. Consider infant gaze following. When watching an adult shift his gaze to look at some salient toy, infants by 9 months of
age shift their gaze to follow the adult’s gaze to that toy. Potentially, infant
gaze following might be produced by an understanding that the agent sees
something—the adult has a visual experience of some sort and that is what
I will see if I look over there. However, infants may instead just automatically and unknowingly match the adult’s behavior, without any deeper
understanding. In fact, young infants often “gaze follow” adults wearing
blindfolds. Yet, in telling research, 12-month-olds were given advance
experience with blindfolds occluding their own vision (Meltzoff & Brooks,
2008). After such experiences, they were significantly less likely to “gaze
follow” a blindfolded adult, suggesting that their sense of what the adult

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can see—visually experience—guided the infants’ actions. By 18 months,
infants do not often gaze follow a blindfolded adult—probably because they
have come to understand that blindfolds occlude visual experience. But,
in this same study, 18-month-olds were given an experience with a special
blindfold that looked opaque yet was easily seen through when worn.
After the experience with that blindfold, 18-month-olds did gaze follow the
head-turn of a blindfolded adult. Thus, by 12–18 months, infants develop
a sense of the person’s visual experience, and it is this awareness of visual
experiences (not just overt eye- or head-directedness) that controls their
gaze following.
CUTTING-EDGE RESEARCH
THE PROGRESSIVE COURSE OF THEORY-OF-MIND DEVELOPMENT
Theory-of-mind understandings begin in infancy, but also progress; earliest
understandings of intentional action give way to a later, richer belief–desire
system of understanding (see Wellman, 2011 for a chapter-length overview
of theory-of-mind development; see Wellman, 2014, for a book-length treatment). Within such a crude progression are several more precise ones. The
best-established progression concerns comparisons between preschool children’s understanding of desires and intentions versus beliefs. When tested
in closely comparable tasks, toddlers evidence an understanding that people
can have differing desires for the exact same object or event, but not that they
may have differing beliefs.
Beyond this shift, more detailed, extended progressions of understanding
characterize theory of mind. A clear example comes from an established
Theory-of-Mind Scale (Wellman & Liu, 2004) that encompasses carefully
constructed tasks assessing childhood understanding of (i) Diverse Desires
(people can have different desires for the same thing, DD), (ii) Diverse
Beliefs (people can have different beliefs about the same situation, DB), (iii)
Knowledge Access (something can be true, but the uninformed are ignorant
of that, KA), (iv) FBs (something can be true, but someone might believe
something different), and (v) Hidden Emotions (someone can feel one way
but display a different emotion, HE). Studies using this carefully scaled battery of tasks, encompassing more than 500 preschoolers in the United States,
Canada, Australia, and Germany, evidence a clear and consistent order of
difficulty. It is of the order listed above, with DDs the easiest, understanding
knowledge and beliefs harder, and HEs the hardest. For shorthand, call this
sequence, DD>DB>KA>FB>HE. This sequence is highly replicable and
significant—80% of these children show the pattern DD>DB>KA>FB>HE.

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UNIVERSALITY
The data for FBs in Box 1 begin to show an intriguing universality in
early theory-of-mind understanding. Young children worldwide evidence
a belief–desire understanding of persons, as indexed by their emerging
false-belief understanding. Current data go beyond such classic findings
to demonstrate universality coupled with intriguing cultural influences on
theory of mind. Research using the Theory-of-Mind Scale clarifies this.
Assume that theory-of-mind understandings are the products of social
and conversational experiences that vary from one community to another.
Western and Chinese childhood experiences could be crucially different.
Various authors have described an Asian focus on persons as sharing group
commonalities and interdependence and a contrasting Western focus on
persons as distinctively individual and independent. These differences
include differing emphases on common knowledge and perspectives versus
emphases on diversity of individual beliefs and perspectives. Moreover,
Western and Chinese adults seem to manifest very different everyday
epistemologies—everyday notions of knowledge, belief, truth, and learning.
Everyday Western epistemology is focused on truth, subjectivity, and belief;
Confucian–Chinese epistemology focuses more on pragmatic knowledge
acquisition and the consensual knowledge that all right-minded persons
should learn. Indeed, in conversation with young children, Chinese parents
comment predominantly on “knowing,” while US parents comment more
on “thinking.”
In accord with such conversational–cultural preferences for emphasizing
knowledge acquisition versus belief differences, Chinese preschoolers evidence a consistent, but different, theory-of-mind sequence where KA (knowledge access) and DB (diverse beliefs) are reversed: DD>KA>DB>FB>HE
rather than DD>DB>KA>FB>HE (Wellman & colleagues, 2006). Both Western and Chinese children first understand the basic aspects of desire (DD),
but after that Western children first appreciate belief differences (DB), while
Chinese children first appreciate knowledge acquisition and access. While
the two sequences are notably similar (pointing to robust, universal processes
of theory-of-mind development), they are also crucially different (pointing to
experience-dependent processes of theory-of-mind learning as well).
An alternative, experience-dependent sequencing is not some singular peculiarity of Chinese mind and development; the same alternative
sequence appears in Iranian preschool children. Despite profound differences in Iran’s Muslim traditions and beliefs in contrast to the Chinese
Confucian/Buddist/Communist ones, both China and Iran share collectivist
family values emphasizing consensual learnings, knowledge acquisition,
and low tolerance for childhood assertions of disagreement and independent

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belief. In parallel, children in Iran display the DD>KA>DB>FB>HE
sequence displayed by Chinese children (Shahaeian & colleagues, 2011).
DEAFNESS
Not only can sequences of theory-of-mind understandings differ (e.g., for
Chinese vs US children), but as Box 1 shows, timetables can differ as well.
Beyond the modest timing differences depicted in Box 1, theory-of-mind
understandings can be seriously delayed. Indeed, as noted before, false-belief
understanding is seriously (not modestly) delayed in children with autism.
Most adolescents and adults with autism perform poorly on false-belief
tasks. But, then, autism is replete with neurological impairments, general
across-the-board cognitive delays. Autism could certainly have its own
delayed maturational timetable. Intriguingly, deaf children often evidence
serious theory-of-mind delays as well. Deaf children do not suffer from
the same central neurological impairments and retardation as individuals
with autism; they have peripheral hearing loss instead. Their data further
emphasize the crucial role of social–conversational experiences in children’s
acquisition and construction of their theories of mind.
Neatly enough, there are two main groups of deaf children to consider. Deaf
children of deaf parents grow up with ordinary conversational, language
experiences—albeit in sign language—and so grow up with others who communicate and interact with them profusely. But, most deaf children—about
95%—are born to hearing parents. They grow up with very different early
experiences. For example, despite valiant efforts to learn sign, hearing parents rarely achieve real proficiency. Especially, when their child is young,
hearing parents mostly communicate with their deaf child using simple signs
or gestures to refer to here and now objects. Also, usually only one person
in the family—often the mother—is the “designated” primary communicator and interactor for the child. The deaf child in a hearing family begins
life with little discourse about persons’ inner states, thoughts, and ideas, is
likely to have restricted play with others, and generally has less access to the
free-flowing, turn-taking, perspective-negotiating dance of social communication and interaction.
Initial research in the 1990s showed that deaf children of hearing parents
(but not deaf children of deaf parents) were substantially delayed in understanding FBs, typically as delayed as high-functioning children with autism
(Peterson & Siegal, 1995). More informatively, when deaf children (of hearing parents) receive the Theory-of-Mind Scale, like hearing children, they
too evidence a consistent sequence of progression, but one that is delayed
at every step of the way (Peterson & colleagues, 2005). It takes deaf children
12 or more years to progressively achieve what hearing children (and deaf
children of deaf parents) progressively achieve in 4–6 years.

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The data for deaf children of hearing parents also speak strongly against
any maturational, critical-period analysis of theory of mind. Deaf children
of hearing parents continue to progress on what are typically “preschool”
theory-of-mind understandings as adolescents and adults.
INFANCY
Recent research claims infants go beyond an understanding of intentional
actions and internal experiences. By 10–15 months, they already recognize
that actors act on the basis of their beliefs and FBs. Box 3 presents the essence
of the initial influential task and findings. Several other demonstrations are
also on offer. These emerging infant “false-belief” studies are clever and
revealing. It remains unclear and controversial, however, how these findings
should best be interpreted. Whether or not these studies reveal a true infant
understanding of FBs, however, I believe they confirm, at a minimum, that
infants understand actors as goal-directed, that infants track the changing
experiences of other persons that yield for them awareness or unawareness
of key events (at least in simplified scenarios), and that infants expect aware
and unaware agents to act differently.

Box 3
A. Familiarization: Agent puts toy in dark box

B. Change: Agent doesn’t see toy move to lighter box

C. Test events: Infant sees agent search, in either
new location

prior location

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Recent research claims that the intention understanding of 1-year-old infants also
includes FB understanding. The initial and most well-known demonstration comes
from Kristine Onishi and Renee Baillargeon (2005), in a familiarization-test paradigm
schematized here. In essence, paralleling standard tasks (Box 1), infants see that the
agent places the object in one location and does not see the object switch locations.
If infants expect the agent to search in the prior location (on the basis of a FB), they
should look longer at the new-location test event. 15-month-old infants do consistently
look longer at new location-test events.
Note, however, that understanding FB requires more than just understanding ignorance. So, alternative interpretations are possible based on an infant understanding of
ignorance rather than FB. For example, if infants understand the agent is unaware (and
thus ignorant of the location of the object), that understanding would be sufficient for
them to see the new-location test event as novel or unexpected (e.g., if the agent is ignorant, she might search in neither place, she might search in both places, she might search
incorrectly, but in any event it would be novel/unexpected to see her search directly in
only the correct location.)

KEY ISSUES FOR FUTURE RESEARCH
It is easy to think of key issues for research going forward. Research is
needed on how theory of mind influences social learning, for example,
how it impacts children’s receptiveness to and learning from others (“testimony”); (Harris, 2012). Research is needed on the interplay between
children’s theory of mind and their emerging moral judgments. Research
is needed on theory of mind beyond childhood development—how does
it operate in adults or in the elderly? For example, is theory of mind party
to the general declines of cognitive aging or is it specially preserved and
resistant to decline?
Three additional future directions for research stand out in my mind.
INFANCY
The emerging data on infants’ understanding of minds, including demonstrations of their understanding of belief-like states (as in Onishi &
Baillargeon, 2005), are intriguing and transformative. Clearly, infants are
deeply attuned to agents’ actions and states. The emerging data on infant
“FBs” are, however, still patchy and unsystematic. They are also interpreted
in widely discrepant ways by various competing researchers. Moreover,
it is far from clear how to reconcile the infant research with that from
preschoolers. Whatever is the best account of infant theory-of-mind development, preschool developments and achievements remain important.
It is the preschool achievements, recall, that relate to children’s social
actions—their popularity with peers, their engagement in social pretense,
and their prosocial and antisocial interactions. The current inconsistencies

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and competing interpretations demand future research with infants and
research reconciling infant and preschool understandings.
DEVELOPMENTAL NEUROSCIENCE
Theory of mind is not only a conceptual achievement characterized by developmental and conceptual-learning processes. It is a cognitive system characterized by distinctive neural bases and processes as well.
Cognitive neuroscientific investigations with adults demonstrate that
theory-of-mind reasoning involves a network of neural regions: the medial
prefrontal cortex (medial PFC) and the left and right temporoparietal junction (TPJ) most consistently, as well as the superior temporal gyrus/superior
temporal sulcus (STG/STS), and the temporal poles (Gallagher & Frith,
2003; Saxe & colleagues, 2004). These regions are recruited when adults
engage in multiple mental-reasoning tasks across functional neuroimaging
(fMRI) and electrophysiological (EEG/ERP) methods alike.
To illustrate, adults show increased BOLD signal (the hemodynamic
response that indexes neural activation and is tracked by fMRI) in bilateral
TPJ, anterior STS, medial PFC when reading stories requiring mental-state
inferences (i.e., inferring thoughts and knowledge states from a series of
human actions and interactions) in contrast to reading nonmental human
descriptions (e.g., nonmental social interactions and descriptions of people’s
appearances).
Even if the adult findings were crystal clear, however, understanding
neurocognitive processes in cognitively expert adults does not translate
to an understanding of brain and cognition earlier in development. Yet,
theory of mind undergoes rapid and stark advancements over infancy
and early childhood. Thus, direct neurocognitive examinations of younger
children—especially in the age range from 2 to 6 or 7 years, when developmental changes are so pronounced—are needed to more clearly address
important and outstanding questions on theory of mind and its development
(for initial research, see Liu & colleagues, 2009; Sabbagh & colleagues, 2009).
As one more concrete example, again consider infant theory-of-mind
understandings. Infant social–cognitive understandings are measured most
consistently with nonverbal, implicit, looking-time methods (Boxes 2 and 3),
and disputes rest highly on questions of how these implicit measures relate
to the explicit, verbal measures used with older children and adults (Box 1).
Potentially, neuroscientific investigations should help us distinguish implicit
versus explicit types of reasoning. Studies that examine neural correlates
as infants perform implicit theory-of-mind tasks could identify neural
similarities and differences between them and older children performing
explicit, standard theory-of-mind tasks.

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THEORY OF MIND AND NAïVE SOCIOLOGY
Theory of mind is often called naïve psychology—our everyday, common
understanding of agents via their psychological, mental states. In this
way, it is distinguishable from several other everyday theories, classically
naïve physics and naïve biology. Using this terminology, humans may well
achieve a naïve sociology (Banaji & Gelman, 2013)—an everyday understanding of social groups (allies and enemies), of social rules (obligations
and privileges), and social categories (gender and race). A key question to
consider is to what extent are naïve sociology and naïve psychology distinct
and to what extent do they overlap? Some theorists attempt to decisively
segregate two very different sorts of social cognition—naïve psychology
versus naïve sociology. But, a long-standing and key claim about theory of
mind is that it is central to all our social cognition—and is foundational to
the way we humans make sense of our social world, our social interactions,
and our social organizations. I believe that theory of mind cannot be neatly
or decisively segregated from these additional societal understandings. On
this perspective, naïve psychology and naïve sociology largely overlap. Not
every social cognition has a psychological face, of course, but still I would
argue that vast portions of the social world—including our understanding
of morality and social rules, social identities and social categories, social
groups and interactions—are grounded in our everyday construal of social
actors as psychological, belief–desire agents. Future research is still needed
to establish the nature and development of social cognition in all its breadth
and interconnections.
REFERENCES
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Baron-Cohen, S. (1995). Mindblindness: An essay on autism and theory of mind. Cambridge, MA: MIT Press.
Brandone, A. C., & Wellman, H. M. (2009). You can’t always get what you want:
Infants understand failed goal-directed actions. Psychological Science, 20(1), 85–91.
doi:10.1111/j.1467-9280.2008.02246.x
Gallagher, H. L., & Frith, C. D. (2003). Functional imaging of ’theory of mind’. Trends
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Gergely, G., Nádasdy, Z., Csibra, G., & Bíró, S. (1995). Taking the intentional stance
at 12 months of age. Cognition, 56(2), 165–193. doi:10.1016/0010-0277(95)00661-h
Harris, P. L. (2012). Trusting what you’re told: How children learn from others. Cambridge,
MA: Belknap Press of Harvard University Press.
Harris, P. L., Pasquini, E. S., Duke, S., Asscher, J. J., & Pons, F. (2006). Germs and
angels: The role of testimony in young children’s ontology. Developmental Science,
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Leekam, S. R., & Perner, J. (1991). Does the autistic child have a metarepresentational
deficit? Cognition, 40(3), 203–218. doi:10.1016/0010-0277(91)90025-Y
Leslie, A. M., & Thaiss, L. (1992). Domain specificity in conceptual development:
Neuropsychological evidence from autism. Cognition, 43(3), 225–251. doi:10.1016/
0010-0277(92)90013-8
Liu, D., Sabbagh, M. A., Gehring, W. J., & Wellman, H. M. (2009). Neural correlates of children’s theory of mind development. Child Development, 80(2), 318–326.
doi:10.1111/j.1467-8624.2009.01262.x
Meltzoff, A. N. (1995). Understanding the intentions of others: Re-enactment of
intended acts by 18-month-old children. Developmental Psychology, 31, 838–850.
Meltzoff, A. N., & Brooks, R. (2008). Self-experience as a mechanism for learning
about others: A training study in social cognition. Developmental Psychology, 44(5),
1257–1265.
Milligan, K., Astington, J. W., & Dack, L. A. (2007). Language and theory of mind:
Meta-analysis of the relation between language ability and false-belief understanding. Child Development, 78(2), 622–646. doi:10.1111/j.1467-8624.2007.01018.x
Onishi, K. H., & Baillargeon, R. (2005). Do 15-month-old infants understand false
beliefs? Science, 308(5719), 255–258. doi:10.1126/science.1107621
Peterson, C. C., & Siegal, M. (1995). Deafness, conversation and theory of mind.
Journal of Child Psychology and Psychiatry, 36(3), 459–474. doi:10.1111/j.14697610.1995.tb01303.x
Peterson, C. C., Wellman, H. M., & Liu, D. (2005). Steps in theory-of-mind development for children with deafness or autism. Child Development, 76(2), 502–517.
doi:10.1111/j.1467-8624.2005.00859.x
Sabbagh, M. A., Bowman, L. C., Evraire, L. E., & Ito, J. M. B. (2009). Neurodevelopmental correlates of theory of mind in preschool children. Child Development, 80(4),
1147–1162. doi:10.1111/j.1467-8624.2009.01322.x
Saxe, R., Carey, S., & Kanwisher, N. (2004). Understanding other minds: Linking
developmental psychology and functional neuroimaging. Annual Review of Psychology, 55, 87–124. doi:10.1146/annurev.psych.55.090902.142044
Shahaeian, A., Peterson, C. C., Slaughter, V., & Wellman, H. M. (2011). Culture and
the sequence of steps in theory of mind development. Developmental Psychology,
47(5), 1239–1247. doi:10.1037/a0023899
Wellman, H. M. (2011). Developing a theory of mind. In U. Goswami (Ed.), The Blackwell handbook of childhood cognitive development (2nd ed., pp. 258–284). New York,
NY: Blackwell.
Wellman, H. M. (2014). Making minds: How theory of mind develops. New York, NY:
Oxford University Press.
Wellman, H. M., Cross, D., & Watson, J. (2001). A meta-analysis of theory-of-mind
development: The truth about false belief. Child Development, 72(3), 655–684.
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Wellman, H. M., Fang, F., Liu, D., Zhu, L., & Liu, G. (2006). Scaling of theory-of-mind
understandings in Chinese children. Psychological Science, 17(12), 1075–1081.
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75(2), 523–541. doi:10.1111/j.1467-8624.2004.00691.x

HENRY WELLMAN SHORT BIOGRAPHY
Henry Wellman was born in Hickory, North Carolina, received his undergraduate degree from Pomona College, was a kindergarten and preschool
teacher for several years, then received his PhD from the Institute of
Child Psychology at the University of Minnesota. Wellman has been at
the University of Michigan for more than 30 years where he is the Harold.
W. Stevenson Collegiate Professor of Psychology. For many years, his
research has focused on children’s developing knowledge of persons. He
has written more than 100 articles and several books including The Child’s
Theory of Mind (1990), (with Karen Bartsch) Children Talk about the Mind
(1995), and Making Minds (2014). He is a former president of the Cognitive
Development Society, recipient of an NIH MERIT Award, recipient of the
University of Michigan’s Distinguished Faculty Achievement Award and
of the American Psychological Association’s G. Stanley Hall Award for
distinguished research contributions to Developmental Psychology. He lives
in Ann Arbor, Michigan, with his wife Karen Lind, and has two sons Ned
and Daniel.
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Theory of Mind

17

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Hongjing Lu



Theory of Mind
HENRY WELLMAN

Abstract
Humans are a social species. We not only live socially, but also think socially, accumulating myriad thoughts and knowledge about our social world. A hallmark of
this human social cognition is an everyday theory of mind––our ordinary human
understanding that persons (self and others) have internal mental states––desires,
beliefs, feelings, hopes—that crucially shape their actions and lives. I review classic
and current knowledge on the nature and importance of theory of mind. Theory of
mind is achieved and changes over human development; so, I emphasize that we
must understand its development. Fortunately, development of this everyday theory of mind is an intriguing story in its own right, and a great portion of the research
on theory of mind is developmental research with typical and atypical infants and
children.

In March 2007, NBCNews.com posted an article headlined “Mindreading
Scientists Predict Behavior.” At a lab in Germany, volunteers in an MRI
machine performed simple tasks of deciding whether to add or subtract
two numbers that they would see a few seconds later. Researchers tried to
read these volunteers’ minds from their brain scans, by judging what the
person intended, in their thoughts before they acted. The researchers, led
by Dr. Haynes in Berlin, were reasonably successful—about 70% accurate
at identifying the subjects’ decisions about whether they would add versus
subtract the two numbers. That made them about 20% more successful than
random guessing. The article cited various enthusiastic reactions and even
ended by noting that some commentators and ethicists are alarmed by the
implications of such mind reading.
Mind reading is indeed amazing. Yet actually, even 2-year olds and
3-year-olds do this sort of thing every day; even infants can succeed at
figuring out someone’s intentions. They succeed not with fancy machines,
but with their fancy 2-year-old brains and their ordinary, still-developing
theory of mind. We all “read minds” in this ordinary (mundane but fully
amazing) way. And we are better than these scientists—not infallible (but
Emerging Trends in the Social and Behavioral Sciences. Edited by Robert Scott and Stephen Kosslyn.
© 2015 John Wiley & Sons, Inc. ISBN 978-1-118-90077-2.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

often better than 70% for simple things like inferring intentions and then
using them to predict behavior) and we are also able to do so in much less
constrained everyday situations. How we do this is the story of theory of
mind (and a great deal of research).
Theory of mind describes our wide-ranging human understanding of
agents’ mental states, such as intentions, desires, and thoughts, and how
action is shaped by such states. It refers to our everyday psychology, appropriately emphasizing the “mind reading” that so strongly characterizes our
everyday, commonsense understandings. Consider Romeo and Juliet. We
easily understand that Romeo loves Juliet and wants to be with her. But he
thinks his parents (and his clansmen) will violently object, so he tries to meet
with her in secret.
Philosophers and psychologists often characterize our everyday theory of
mind as a belief–desire psychology. Such an everyday psychology provides
explanations and predictions of action by appeal to what the person thinks,
knows, and expects, coupled with what he or she wants, intends, and hopes
for. Why did Romeo meet Juliet secretively: He wanted to be with her, and
thought his kinsmen would interfere. Everyday psychological reasoning also
includes reasoning about the origins of mental states (Romeo wants to be
with Juliet because he loves her; he thinks his kinsmen will violently object
because he has seen their violence in the past). That is, beyond beliefs and
desires, theory of mind incorporates a variety of related constructs such as
drives and preferences that ground one’s desires, and perceptual–historical
experiences that ground one’s beliefs. It also includes emotional reactions
that result from these desires, beliefs, preferences, and perceptions: happiness at fulfilled desires, frustration at unfulfilled desires, surprise when
events contradict one’s firmly held beliefs.
Acquisition of this everyday theory of mind may be one of the most
impressive intellectual accomplishments of human development. Much
like human language, theory of mind is notably abstract, but accomplished
in basic forms rapidly by young children everywhere. And, again like
language, both intriguing early competences and striking developments are
readily apparent: Infants closely attend to other humans; 2-year-olds talk
about persons’ wants and feelings and comfort others in distress; 3-year-olds
and 4-year-olds talk about thoughts and begin to engage in lies and trickery;
and nuanced theories of mind—in adults’ “folk psychologies”—are apparent
in (and dramatically differ across) cultural communities worldwide. Indeed,
revealing developmental data showing near-universal attribution by young
children of mental states to self and others has helped fuel rampant contemporary interest in theory of mind. Lay adults and children are embedded
in theory of mind; scientists, scholars, and the newsreading public are now
immersed in it.

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FOUNDATIONAL RESEARCH
Think about Romeo and Juliet again. Theirs is a story about love and desire,
but love and desire gone awry. At the end of the play, down in the crypt,
Romeo still desires Juliet who is alive and well right beside him, but he kills
himself. Why? Because, he believes she is dead. Understanding the possibility
of an internal realm of mental representations (ideas, thoughts, images) is
a hallmark of theory of mind. Understanding false beliefs (FBs), when contents of the world (Juliet is alive) contradict the contents of thought (“Juliet
is dead”), provides a powerful illustration of such everyday understanding.
This is one reason why there has been so much research on children’s
understanding of FBs (hundreds of studies and thousands of children
encompassed in several meta-analyses, e.g., Milligan & colleagues, 2007;
Wellman & colleagues, 2001). Another reason for this voluminous research
is that when researchers were first becoming interested in theory of mind,
several easy-to-use, “standard” false-belief tasks were developed of the
sort depicted in Box 1. And these have proved nicely revealing. For one,
they consistently show an important developmental transition. Indeed, as
graphed in Box 1, because they have been used worldwide, false-belief tasks
reveal a universal childhood theory-of-mind developmental achievement.
Worldwide, children go from consistent false-belief errors to consistently
correct understanding of FBs during early childhood. The timing of coming
to understand FBs can also differ intriguingly across countries.

Box 1

FB tasks have children (or adults) reason about an agent whose actions should be controlled by an FB. Such tasks have many forms, but a common task employs a change in
locations, as depicted above. The child (not shown above) sees the character, Jill, puts
her candy in the drawer. Jill leaves and, while she cannot see, the candy gets moved to
the cupboard. Jill returns, wants her candy, and the child is asked “Where will Jill look
for her candy?” or “Where does Jill think her candy is?” Older children answer correctly, like adults. Younger children answer incorrectly; they are not just random they
consistently say Jill will search in the cupboard (where it really is). Note that the task
taps more than just attribution of ignorance (Jill doesn’t know) rather attribution of FB
(Jill thinks—falsely—her candy is in the drawer).

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Country
5
4
Proportion correct (logit)

Australia
3
2

Austria
Canada
Japan

1
0

USA

−1
−2

Hong Kong

−3
−4
−5

England
30

40

50

60

70

80

90

100 110

Age (months)
(Data from Wellman and colleagues
2001; Liu and colleagues 2008.)

A frequently used alternative task uses deceptive contents (rather than change of location). For example, children see a crayon box, say they think it holds crayons, then upon
opening see it holds candies. They are asked what someone else who has never looked
inside will think the box holds—crayons or candies.
Several factors make such tasks harder or easier, but nonetheless children go from consistently below -chance to above-chance performance, typically in the preschool years.
Moreover, as shown in the graph at left, children in different cultural-linguistic communities can achieve FB understanding somewhat more quickly or more slowly, yet
in all locales they evidence the same trajectory—from below-chance to above-chance
performance in early to middle childhood. This is true even for children growing up
in non-western cultural communities speaking non-Indo-European languages. And is
true even for children in traditional, nonliterate societies.

There is more to say about FBs, but a focus on a single task or achievement
is limited and misleading. So, importantly, other research shows that by 4–6
years, children not only expect people to act in accord with their beliefs but
also explain persons’ actions by citing their mental states, including their
beliefs; they also come to understand about lies and deception, appearances
versus reality, that someone’s external expressions need not display their
internal emotions, and more. As a single intriguing example, 3-year-old
and 4-year-old children explicitly judge that a person’s ideas, thoughts, and
dreams are “internal,” immaterial, private experiences in contrast to real,
concrete, overt physical events (Harris & colleagues, 2006; Wellman & Estes,
1986).

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5

SOCIAL ACTION
Children’s development of this network of belief–desire reasoning dramatically impacts their actions and interactions with others. One way to
appreciate this is to note that amid the consistent trajectories shown in Box 1,
there is also obvious variation. Although almost all normally developing
children eventually master FBs, some children (not only across countries, but
also within any cultural–language community) come to this understanding
somewhat earlier and some later. This variation has been important for
identifying outcomes that are influenced by theory-of-mind understandings.
Indeed, differences in FB understanding, as measured in the preschool years,
predict several key childhood competences, such as how and how much
children talk about people in everyday conversation, their engagement
in pretense, their social interactional skills, and consequently their interactions and popularity with peers. Preschool variation in theory-of-mind
understanding also influences children’s use of deception, their strategies
for arguing with and persuading others, and their actions in games like
Hide-and-Seek. These findings reveal and confirm theory of mind’s real-life
relevance. (See Wellman, 2014, Chapter 3, for a review.)
AUTISM
What would social understanding and social interaction be like for someone
with an impaired theory of mind? A long-standing proposal is that individuals with autism might approximate such a case—the “theory-of-mind
hypothesis for autism.” Indeed, in classic studies, school-age children and
adolescents with autism were given standard false-belief tasks much like
the one depicted in Box 1. Although the tasks were largely nonverbal (and
children could respond merely by pointing), and although individuals with
autism were correct on all the related control questions, they were consistently incorrect on the false-belief judgments themselves. In comparison, not
only are younger typically developing 4-, 5-, and 6-year-olds consistently correct, older children with Down’s Syndrome, matched in age to those with
autism, are also consistently correct (Baron-Cohen, 1995).
The consensus perspective on theory of mind is that it targets a special
sort of reasoning about the social domain of agents’ actions and minds.
But, perhaps, theory of mind is really just a straightforward manifestation
of more domain-general cognitive processes such as memory, inference,
and executive functioning. And, similarly, perhaps those are the critical
deficits for autism, not something more specially social–cognitive. In this
regard, high-functioning autistics’ performance with false photographs
versus FBs has proved revealing. False-belief tasks are outlined in Box 1;
false-photograph tasks are comparable in format, but target not mental

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

representations that are outdated and so false but rather outdated photos
that no longer match what is so. High-functioning autistics that consistently fail false-belief tasks consistently pass parallel false-photo tasks
(Leekam & Perner, 1991; Leslie & Thaiss, 1992). Because these individuals’
memory, attention, learning, and executive functioning are sufficient to
understand false photos, such domain-general processing factors fail to
account for their parallel difficulties with FBs. Data such as these help
confirm that theory of mind is a specialized and distinctive form of social
understanding.
At the same time, it is important to note that almost no researchers or clinicians today argue that autism deficits are solely characterized or caused by
theory-of-mind deficits.
INFANCY
Classically, theory-of-mind research began with older children, such as
preschoolers, and moved backward. It is now clear that understanding of
people in terms of their internal, psychological states begins in infancy.
The earliest examples of psychological construals of persons appear in
intention understandings; by the end of the first year, children begin to treat
themselves and others as intentional agents. Box 2 presents an example of
just one method used to demonstrate intention understanding in infants
(from Brandone & Wellman, 2009). In the initial demonstrations, using something like this paradigm, infants saw an animated circle “jumping” over a
barrier to reach its goal object. Just as they do for intentional human acts
like reaching, 9- and 12-month-olds look longer at the animated indirect test
events over the direct ones, showing an abstract, generalized understanding
of intentional agency (Gergley & colleagues, 1995).
Infant understandings of intentional action appear not only in looking-time
research but also in more active–interactive paradigms. A classic study of
this type went beyond examining infant understanding of successful actions
(e.g., a reach that successfully retrieves an object, as in Box 2) to consider
understanding of failed actions (Meltzoff, 1995). Arguably, inferring a goal
when it is unfulfilled, and thus nonovert in the actor’s movements or
outcomes, demonstrates a still deeper understanding that intentions exist
beneath the surface of performed actions. So, in this study, 18-month-olds
witnessed an adult try but fail to fulfill several novel, object-directed goals
(e.g., trying to hang a ring on a hook). Although infants never saw the actions
successfully modeled, when given a chance to act on the objects themselves,
they “imitated” the successful action much more than the failed (actually

Theory of Mind

7

witnessed) actions. So, they understood the action’s goal even when it was
never observed.

Box 2

Habituation event

Direct reach test event

Indirect reach test event

Habituation-test (or familiarization-test) looking-time paradigms set the infant up so
that he or she will then look longer at novel, unexpected test events. In the reaching
paradigm (above), infants view multiple trials of the barrier-reaching event in habituation. Then, the barrier is removed and the test events contrast two different construals of
the person’s actions, one in terms of intentions and one in terms of physical motions of
the body. Suppose during habituation the infant construes the actor’s action in terms of
its physical movement (the arm and hand up and then down in an arc), then the indirect reach test event should be expected (as it repeats the same movement), whereas
the direct reach will stand out as novel and so specially attention-worthy. In contrast,
if the infant initially construes the action as goal directed, then when the barrier is
removed the direct reach is the expected action because there the actor continues to
directly seek the goal. Under this second construal, the indirect reach would be more
attention-worthy because (although the actor’s arm movement remains the same as during habituation) the actor no longer seems straightforwardly directed to the goal. Infants
who are 8, 9, 10, and 12 months old consistently look longer at the indirect test event.
Infants look equally to both test events in control conditions where they are first habituated to a display with no barrier or first habituated to the exact same over-the-barrier
arm movements but where there is no goal-object.

Key infant understandings encompass their understanding of intentional
action and internal experience. Consider infant gaze following. When watching an adult shift his gaze to look at some salient toy, infants by 9 months of
age shift their gaze to follow the adult’s gaze to that toy. Potentially, infant
gaze following might be produced by an understanding that the agent sees
something—the adult has a visual experience of some sort and that is what
I will see if I look over there. However, infants may instead just automatically and unknowingly match the adult’s behavior, without any deeper
understanding. In fact, young infants often “gaze follow” adults wearing
blindfolds. Yet, in telling research, 12-month-olds were given advance
experience with blindfolds occluding their own vision (Meltzoff & Brooks,
2008). After such experiences, they were significantly less likely to “gaze
follow” a blindfolded adult, suggesting that their sense of what the adult

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

can see—visually experience—guided the infants’ actions. By 18 months,
infants do not often gaze follow a blindfolded adult—probably because they
have come to understand that blindfolds occlude visual experience. But,
in this same study, 18-month-olds were given an experience with a special
blindfold that looked opaque yet was easily seen through when worn.
After the experience with that blindfold, 18-month-olds did gaze follow the
head-turn of a blindfolded adult. Thus, by 12–18 months, infants develop
a sense of the person’s visual experience, and it is this awareness of visual
experiences (not just overt eye- or head-directedness) that controls their
gaze following.
CUTTING-EDGE RESEARCH
THE PROGRESSIVE COURSE OF THEORY-OF-MIND DEVELOPMENT
Theory-of-mind understandings begin in infancy, but also progress; earliest
understandings of intentional action give way to a later, richer belief–desire
system of understanding (see Wellman, 2011 for a chapter-length overview
of theory-of-mind development; see Wellman, 2014, for a book-length treatment). Within such a crude progression are several more precise ones. The
best-established progression concerns comparisons between preschool children’s understanding of desires and intentions versus beliefs. When tested
in closely comparable tasks, toddlers evidence an understanding that people
can have differing desires for the exact same object or event, but not that they
may have differing beliefs.
Beyond this shift, more detailed, extended progressions of understanding
characterize theory of mind. A clear example comes from an established
Theory-of-Mind Scale (Wellman & Liu, 2004) that encompasses carefully
constructed tasks assessing childhood understanding of (i) Diverse Desires
(people can have different desires for the same thing, DD), (ii) Diverse
Beliefs (people can have different beliefs about the same situation, DB), (iii)
Knowledge Access (something can be true, but the uninformed are ignorant
of that, KA), (iv) FBs (something can be true, but someone might believe
something different), and (v) Hidden Emotions (someone can feel one way
but display a different emotion, HE). Studies using this carefully scaled battery of tasks, encompassing more than 500 preschoolers in the United States,
Canada, Australia, and Germany, evidence a clear and consistent order of
difficulty. It is of the order listed above, with DDs the easiest, understanding
knowledge and beliefs harder, and HEs the hardest. For shorthand, call this
sequence, DD>DB>KA>FB>HE. This sequence is highly replicable and
significant—80% of these children show the pattern DD>DB>KA>FB>HE.

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9

UNIVERSALITY
The data for FBs in Box 1 begin to show an intriguing universality in
early theory-of-mind understanding. Young children worldwide evidence
a belief–desire understanding of persons, as indexed by their emerging
false-belief understanding. Current data go beyond such classic findings
to demonstrate universality coupled with intriguing cultural influences on
theory of mind. Research using the Theory-of-Mind Scale clarifies this.
Assume that theory-of-mind understandings are the products of social
and conversational experiences that vary from one community to another.
Western and Chinese childhood experiences could be crucially different.
Various authors have described an Asian focus on persons as sharing group
commonalities and interdependence and a contrasting Western focus on
persons as distinctively individual and independent. These differences
include differing emphases on common knowledge and perspectives versus
emphases on diversity of individual beliefs and perspectives. Moreover,
Western and Chinese adults seem to manifest very different everyday
epistemologies—everyday notions of knowledge, belief, truth, and learning.
Everyday Western epistemology is focused on truth, subjectivity, and belief;
Confucian–Chinese epistemology focuses more on pragmatic knowledge
acquisition and the consensual knowledge that all right-minded persons
should learn. Indeed, in conversation with young children, Chinese parents
comment predominantly on “knowing,” while US parents comment more
on “thinking.”
In accord with such conversational–cultural preferences for emphasizing
knowledge acquisition versus belief differences, Chinese preschoolers evidence a consistent, but different, theory-of-mind sequence where KA (knowledge access) and DB (diverse beliefs) are reversed: DD>KA>DB>FB>HE
rather than DD>DB>KA>FB>HE (Wellman & colleagues, 2006). Both Western and Chinese children first understand the basic aspects of desire (DD),
but after that Western children first appreciate belief differences (DB), while
Chinese children first appreciate knowledge acquisition and access. While
the two sequences are notably similar (pointing to robust, universal processes
of theory-of-mind development), they are also crucially different (pointing to
experience-dependent processes of theory-of-mind learning as well).
An alternative, experience-dependent sequencing is not some singular peculiarity of Chinese mind and development; the same alternative
sequence appears in Iranian preschool children. Despite profound differences in Iran’s Muslim traditions and beliefs in contrast to the Chinese
Confucian/Buddist/Communist ones, both China and Iran share collectivist
family values emphasizing consensual learnings, knowledge acquisition,
and low tolerance for childhood assertions of disagreement and independent

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

belief. In parallel, children in Iran display the DD>KA>DB>FB>HE
sequence displayed by Chinese children (Shahaeian & colleagues, 2011).
DEAFNESS
Not only can sequences of theory-of-mind understandings differ (e.g., for
Chinese vs US children), but as Box 1 shows, timetables can differ as well.
Beyond the modest timing differences depicted in Box 1, theory-of-mind
understandings can be seriously delayed. Indeed, as noted before, false-belief
understanding is seriously (not modestly) delayed in children with autism.
Most adolescents and adults with autism perform poorly on false-belief
tasks. But, then, autism is replete with neurological impairments, general
across-the-board cognitive delays. Autism could certainly have its own
delayed maturational timetable. Intriguingly, deaf children often evidence
serious theory-of-mind delays as well. Deaf children do not suffer from
the same central neurological impairments and retardation as individuals
with autism; they have peripheral hearing loss instead. Their data further
emphasize the crucial role of social–conversational experiences in children’s
acquisition and construction of their theories of mind.
Neatly enough, there are two main groups of deaf children to consider. Deaf
children of deaf parents grow up with ordinary conversational, language
experiences—albeit in sign language—and so grow up with others who communicate and interact with them profusely. But, most deaf children—about
95%—are born to hearing parents. They grow up with very different early
experiences. For example, despite valiant efforts to learn sign, hearing parents rarely achieve real proficiency. Especially, when their child is young,
hearing parents mostly communicate with their deaf child using simple signs
or gestures to refer to here and now objects. Also, usually only one person
in the family—often the mother—is the “designated” primary communicator and interactor for the child. The deaf child in a hearing family begins
life with little discourse about persons’ inner states, thoughts, and ideas, is
likely to have restricted play with others, and generally has less access to the
free-flowing, turn-taking, perspective-negotiating dance of social communication and interaction.
Initial research in the 1990s showed that deaf children of hearing parents
(but not deaf children of deaf parents) were substantially delayed in understanding FBs, typically as delayed as high-functioning children with autism
(Peterson & Siegal, 1995). More informatively, when deaf children (of hearing parents) receive the Theory-of-Mind Scale, like hearing children, they
too evidence a consistent sequence of progression, but one that is delayed
at every step of the way (Peterson & colleagues, 2005). It takes deaf children
12 or more years to progressively achieve what hearing children (and deaf
children of deaf parents) progressively achieve in 4–6 years.

Theory of Mind

11

The data for deaf children of hearing parents also speak strongly against
any maturational, critical-period analysis of theory of mind. Deaf children
of hearing parents continue to progress on what are typically “preschool”
theory-of-mind understandings as adolescents and adults.
INFANCY
Recent research claims infants go beyond an understanding of intentional
actions and internal experiences. By 10–15 months, they already recognize
that actors act on the basis of their beliefs and FBs. Box 3 presents the essence
of the initial influential task and findings. Several other demonstrations are
also on offer. These emerging infant “false-belief” studies are clever and
revealing. It remains unclear and controversial, however, how these findings
should best be interpreted. Whether or not these studies reveal a true infant
understanding of FBs, however, I believe they confirm, at a minimum, that
infants understand actors as goal-directed, that infants track the changing
experiences of other persons that yield for them awareness or unawareness
of key events (at least in simplified scenarios), and that infants expect aware
and unaware agents to act differently.

Box 3
A. Familiarization: Agent puts toy in dark box

B. Change: Agent doesn’t see toy move to lighter box

C. Test events: Infant sees agent search, in either
new location

prior location

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

Recent research claims that the intention understanding of 1-year-old infants also
includes FB understanding. The initial and most well-known demonstration comes
from Kristine Onishi and Renee Baillargeon (2005), in a familiarization-test paradigm
schematized here. In essence, paralleling standard tasks (Box 1), infants see that the
agent places the object in one location and does not see the object switch locations.
If infants expect the agent to search in the prior location (on the basis of a FB), they
should look longer at the new-location test event. 15-month-old infants do consistently
look longer at new location-test events.
Note, however, that understanding FB requires more than just understanding ignorance. So, alternative interpretations are possible based on an infant understanding of
ignorance rather than FB. For example, if infants understand the agent is unaware (and
thus ignorant of the location of the object), that understanding would be sufficient for
them to see the new-location test event as novel or unexpected (e.g., if the agent is ignorant, she might search in neither place, she might search in both places, she might search
incorrectly, but in any event it would be novel/unexpected to see her search directly in
only the correct location.)

KEY ISSUES FOR FUTURE RESEARCH
It is easy to think of key issues for research going forward. Research is
needed on how theory of mind influences social learning, for example,
how it impacts children’s receptiveness to and learning from others (“testimony”); (Harris, 2012). Research is needed on the interplay between
children’s theory of mind and their emerging moral judgments. Research
is needed on theory of mind beyond childhood development—how does
it operate in adults or in the elderly? For example, is theory of mind party
to the general declines of cognitive aging or is it specially preserved and
resistant to decline?
Three additional future directions for research stand out in my mind.
INFANCY
The emerging data on infants’ understanding of minds, including demonstrations of their understanding of belief-like states (as in Onishi &
Baillargeon, 2005), are intriguing and transformative. Clearly, infants are
deeply attuned to agents’ actions and states. The emerging data on infant
“FBs” are, however, still patchy and unsystematic. They are also interpreted
in widely discrepant ways by various competing researchers. Moreover,
it is far from clear how to reconcile the infant research with that from
preschoolers. Whatever is the best account of infant theory-of-mind development, preschool developments and achievements remain important.
It is the preschool achievements, recall, that relate to children’s social
actions—their popularity with peers, their engagement in social pretense,
and their prosocial and antisocial interactions. The current inconsistencies

Theory of Mind

13

and competing interpretations demand future research with infants and
research reconciling infant and preschool understandings.
DEVELOPMENTAL NEUROSCIENCE
Theory of mind is not only a conceptual achievement characterized by developmental and conceptual-learning processes. It is a cognitive system characterized by distinctive neural bases and processes as well.
Cognitive neuroscientific investigations with adults demonstrate that
theory-of-mind reasoning involves a network of neural regions: the medial
prefrontal cortex (medial PFC) and the left and right temporoparietal junction (TPJ) most consistently, as well as the superior temporal gyrus/superior
temporal sulcus (STG/STS), and the temporal poles (Gallagher & Frith,
2003; Saxe & colleagues, 2004). These regions are recruited when adults
engage in multiple mental-reasoning tasks across functional neuroimaging
(fMRI) and electrophysiological (EEG/ERP) methods alike.
To illustrate, adults show increased BOLD signal (the hemodynamic
response that indexes neural activation and is tracked by fMRI) in bilateral
TPJ, anterior STS, medial PFC when reading stories requiring mental-state
inferences (i.e., inferring thoughts and knowledge states from a series of
human actions and interactions) in contrast to reading nonmental human
descriptions (e.g., nonmental social interactions and descriptions of people’s
appearances).
Even if the adult findings were crystal clear, however, understanding
neurocognitive processes in cognitively expert adults does not translate
to an understanding of brain and cognition earlier in development. Yet,
theory of mind undergoes rapid and stark advancements over infancy
and early childhood. Thus, direct neurocognitive examinations of younger
children—especially in the age range from 2 to 6 or 7 years, when developmental changes are so pronounced—are needed to more clearly address
important and outstanding questions on theory of mind and its development
(for initial research, see Liu & colleagues, 2009; Sabbagh & colleagues, 2009).
As one more concrete example, again consider infant theory-of-mind
understandings. Infant social–cognitive understandings are measured most
consistently with nonverbal, implicit, looking-time methods (Boxes 2 and 3),
and disputes rest highly on questions of how these implicit measures relate
to the explicit, verbal measures used with older children and adults (Box 1).
Potentially, neuroscientific investigations should help us distinguish implicit
versus explicit types of reasoning. Studies that examine neural correlates
as infants perform implicit theory-of-mind tasks could identify neural
similarities and differences between them and older children performing
explicit, standard theory-of-mind tasks.

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EMERGING TRENDS IN THE SOCIAL AND BEHAVIORAL SCIENCES

THEORY OF MIND AND NAïVE SOCIOLOGY
Theory of mind is often called naïve psychology—our everyday, common
understanding of agents via their psychological, mental states. In this
way, it is distinguishable from several other everyday theories, classically
naïve physics and naïve biology. Using this terminology, humans may well
achieve a naïve sociology (Banaji & Gelman, 2013)—an everyday understanding of social groups (allies and enemies), of social rules (obligations
and privileges), and social categories (gender and race). A key question to
consider is to what extent are naïve sociology and naïve psychology distinct
and to what extent do they overlap? Some theorists attempt to decisively
segregate two very different sorts of social cognition—naïve psychology
versus naïve sociology. But, a long-standing and key claim about theory of
mind is that it is central to all our social cognition—and is foundational to
the way we humans make sense of our social world, our social interactions,
and our social organizations. I believe that theory of mind cannot be neatly
or decisively segregated from these additional societal understandings. On
this perspective, naïve psychology and naïve sociology largely overlap. Not
every social cognition has a psychological face, of course, but still I would
argue that vast portions of the social world—including our understanding
of morality and social rules, social identities and social categories, social
groups and interactions—are grounded in our everyday construal of social
actors as psychological, belief–desire agents. Future research is still needed
to establish the nature and development of social cognition in all its breadth
and interconnections.
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HENRY WELLMAN SHORT BIOGRAPHY
Henry Wellman was born in Hickory, North Carolina, received his undergraduate degree from Pomona College, was a kindergarten and preschool
teacher for several years, then received his PhD from the Institute of
Child Psychology at the University of Minnesota. Wellman has been at
the University of Michigan for more than 30 years where he is the Harold.
W. Stevenson Collegiate Professor of Psychology. For many years, his
research has focused on children’s developing knowledge of persons. He
has written more than 100 articles and several books including The Child’s
Theory of Mind (1990), (with Karen Bartsch) Children Talk about the Mind
(1995), and Making Minds (2014). He is a former president of the Cognitive
Development Society, recipient of an NIH MERIT Award, recipient of the
University of Michigan’s Distinguished Faculty Achievement Award and
of the American Psychological Association’s G. Stanley Hall Award for
distinguished research contributions to Developmental Psychology. He lives
in Ann Arbor, Michigan, with his wife Karen Lind, and has two sons Ned
and Daniel.
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