Theory of Mind (ToM)

What is Theory of Mind (ToM)?

Theory of Mind (ToM) refers to the commonsense ability to attribute mental states (such as beliefs, desires, and intentions) to one’s self and to other people as a way of making sense of and predicting behavior.

ToM is fundamental to humans’ everyday social interaction and mind reading. It is used when analyzing, judging, and inferring others' behaviors.

For example, your thought that “John thinks I ate his sandwich” reflects a basic understanding that John has internal mental states much like your own, though the specific content of those mental states may differ from your own (in this case, perhaps you believe that Mary ate John’s sandwich).

Studies have shown that some humans use their ToM capabilities to think about other human’s mental states (e.g., “John believes that I intend to make him believe that I didn’t crave his sandwich”). Indeed, ToM is a sophisticated thought process that is more often identified with humans.

In a typically developing child, a coherent theory of mind emerges between ages 3 and 5 (although rudiments of this skill, such as following another person’s gaze to understand what she is looking at, appear earlier). Theory of mind deficits is one major symptom of autism, a psychological disorder that usually appears early in life (other psychological disorders or brain injuries can also produce empathy deficits).

It is believed that other species have either highly limited or, more often the case, no ToM abilities resembling those of humans. Thus, ToM may be one of the crucial attributes that distinguish humans’ social lives from the experience and behavior of all other social animals. Also, among humans, it is possible that newborn babies do not have a Tom, and so child psychologists are very interested in understanding when and how children acquire this ability. (Roy F. Baumeister & Kathleen D. Vohs, Encyclopedia of Social Psychology, Vol 1).

Although, other species may communicate with elaborate signaling and vocalizationsOpens in new window, but they are probably not drawing on a rich understanding of mental states and how they influence behavior. How they interact socially is characterized in the same way as humans interact.

Say for example, you do this-and-that to operate a vending machine, and it functions responsively in a useful and predictable way, but that doesn’t make you believe that it thinks, feels, or for that matter, has any intention of its own.

Historical Background

The Theory of Mind was coined by two primatologists, David PremackOpens in new window and Guy Woodruff, specifically to respond to their curiosity as to whether chimpanzees could use abstract concepts such as desire and memory to interpret others’ behavior. Much of the matter is controversial, but ToM capabilities seems unique and only confined to human.

In addition to primatologists, scholars in diverse fields of study have also shown interest in ToM. Evolutionary psychologists have noted that the evolution of human language and social cooperation may have built on ToM. That is, without ToM, human language probably would not have developed into its present state. Some philosophers contend that ToM centers on human consciousness, since the appreciation that one’s perception of the world may differ from others’ requires knowing that one knows (i.e., metacognition).

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The most extensive ToM research comes from developmental psychologists. ToM may seem like a perfectly obvious and basic capacity, but humans are not born with it.

As the psychologist Jean PiagetOpens in new window noted, young children have difficulty appreciating that their construal of reality may not be shared by everyone. Gradually they begin to understand that their mental states are unique to their perspective and begin to represent others’ perspectives based on knowledge of their mental states.

ToM is often assessed in children using a false belief task:
Show a child that a container labeled “lollipops” actually contains pencils rather than the expected candy. Ask the child what someone else who has not seen the contents of the container will think it contains.

Most 3-years-olds incorrectly predict “pencils,” whereas most 4-year-olds predict “lollipops.” Passing this test requires thinking through what another person would think given knowledge that differs from one’s own(Roy F. Baumeister & Kathleen D. Vohs, Encyclopedia of Social Psychology, Vol. 1).

Implications for Everyday Life

Everyday social activities such as communicating, navigating public spaces, or outsmarting a basketball opponent, depend crucially on everyday mind reading.

How fundamental ToM is to everyday social life isn’t realized until seeing cases where it is impaired. This seems to be the case with autistic individuals, who lack normal social insight and communication skills in part because of selective deficits in the capacity to reason about others’ mental states.

The following are some everyday social phenomena involving ToM.


In normal, reciprocal communicationOpens in new window, a person uses ToM to monitor whether the person and his or her communication partner are still attending to the same topic, to shift topics, and to discus imaginary or hypothetical situations.

ToM is also instrumental in understanding subtle or indirect meanings, such as those coveyed through sarcasmOpens in new window, humorOpens in new window, and nonverbal communicationOpens in new window (e.g., facial expressionsOpens in new window). Conversely, everyday types of miscommunicationOpens in new window occur when people fail to take into account each other’s perspective. For example, you might be confused if a friend called and abruptly announced, “I refuse to do that!” because she has failed to think through what knowledge is only in her head and what knowledge is mutually shared, or common ground.


The ability to reason about what others think, and how certain messages are likely to affect attitudes, is critical for influencing beliefs and actions. For example, if you attempted to use persuasion to influence your boss’s attitude about the importance of conserving water, you would need to adopt his or her point of view and to anticipate his or her reactions to your persuasive appeal.

On a similar note, effectively deceiving someone, from telling a white lie to staging an elaborate ruse, demands that the deceiver see the world through another’s eyes. It would be quite impossible to tailor a persuasive or deceptive message without first appreciating what others already know, want, or feel.

Empathy and Helping

Imagine seeing someone struggling to open a door while negotiating six bags of groceries and three children. Would you offer help even if there was nothing in it for you?

According to Daniel BatsonOpens in new window, if you empathize with the person—that is, vicariously experience the person’s suffering—you will be likely to help regardless of what you stand to gain by doing so. Whether a person lends a hand to those in need can thus depend crucially on his or her ability to put him or herself in their shoes, to experience events and emotions the way they experience them.

Explaining Behavior

People often act as amateur psychologists, trying to interpret others using what Fritz HeiderOpens in new window called a naïve or commonsense psychology about how minds and actions interrelate. People use information about traits and situations, but they also interpret others’ actions from the perspective of their predisposing desires and beliefs (“He’s upset because he thinks I ate his sandwich”).

Interestingly, people are also prone to attribute human-like mental states to nonhuman entities that presumably don’t have minds (“This butterfly came by to cheer me up!” or “I think my computer hates me!”). Cultural practices (e.g., rain dances) and beliefs (e.g., karma, fate) suggest that the young child’s animism, the belief that the physical world is endowed with mental life, retains its appeal well into adulthood.

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