What is Theory of Mind in Psychology?

The psychology behind understanding other people's thoughts and actions

Two children are seated at a table and one is whispering to the other.
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Theory of mind refers to the ability to understand the mental states of others and to recognize that those mental states may differ from our own. Developing a theory of mind is a key stage of child development. A well-developed theory of mind helps us solve conflicts, develop social skills, and predict other people's behavior. 

Assessing Theory of Mind

Psychologists often assess a child's developing theory of mind by performing the .

In the most common version of this task, the researcher will ask the child to observe two puppets: Sally and Anne. The first puppet, Sally, places a marble in a basket, then leaves the room. When Sally is gone, the second puppet, Anne, moves Sally’s marble from the basket to a box. The researcher then asks the child, "Where will Sally look for her marble when she comes back?" 

A child with a robust theory of mind will respond that Sally will look for her marble in the basket. Even though the child knows the basket is not the actual location of the marble, the child is aware that Sally does not know this, and consequently understands that Sally will look for her marble in its former location. Children without fully developed theories of mind may respond that Sally will look in the box. This response suggests that the child is not yet able to recognize the difference between what he or she knows and what Sally knows.


The Development of Theory of Mind

Children typically begin to answer false belief questions correctly around age four. In one meta-analysis, researchers found that children under age three usually answer false belief questions incorrectly, three and a half year olds answer correctly approximately half the time, and the proportion of correct responses continues to increase with age.


Importantly, theory of mind is . An individual may understand others’ mental states in some situations, but struggle with more nuanced scenarios. For example, someone could pass the false belief test but still struggle to understand figurative (nonliteral) speech. One especially of theory of mind involves trying to assess someone's emotional state based only on photographs of their eyes. 

The Role of Language

Research suggests that our use of language may play a role in the development of theory of mind. In order to assess this theory, a group of participants in Nicaragua who were deaf and had varying levels of exposure to sign language. The study found that participants who had exposure to less complex sign language tended to answer false belief questions incorrectly, while the participants who had exposure to more complex sign language tended to answer the questions correctly. Moreover, when the participants who initially had less exposure learned more words (particularly words related to mental states), they began to answer false belief questions correctly. 

However, other research suggests that children develop some understanding of theory of mind even before they can talk.

In , researchers tracked the eye movements of toddlers while answering a false belief question. The study found that even when the toddlers answered the question about false beliefs incorrectly, they looked at the correct answer.  For example, in the Sally-Anne scenario above, the toddlers would look at the basket (the correct answer) while stating that Sally would look for her marble in the box (the incorrect answer). In other words, very young children may have some understanding of theory of mind, even before they can verbalize it.

Theory of Mind and Autism

The researcher Simon Baron-Cohen at the University of Cambridge has suggested that difficulties with theory of mind may be a key component of autism. Baron-Cohen conducted a comparing the performance of children with autism, children with Down syndrome, and neurotypical children on a false beliefs task.

The researchers found that about 80% of neurotypical children and children with Down syndrome answered correctly. However, only about 20% of children with autism answered correctly. Baron-Cohen concluded that this difference in theory of mind development may explain why people with autism sometimes find certain types of social interactions confusing or difficult.

When discussing theory of mind and autism, it’s important to recognize that understanding others’ mental states (i.e. theory of mind) is not the same as caring about others’ feelings. Individuals who have trouble with theory of mind tasks nonetheless feel the same levels of compassion as those who answer theory of mind questions correctly.  

Key Takeaways

  • Theory of mind refers to the ability to understand the mental states of others and to recognize that those mental states may differ from our own.
  • Theory of mind plays an important role in solving conflicts and developing social skills.
  • Children typically develop an understanding of theory of mind around age four, although some research suggests it may start developing even earlier.
  • Some studies have shown that individuals with autism may have more difficulty than others answering theory of mind questions correctly. These findings might explain why people with autism sometimes find certain social situations confusing.


  • Baron-Cohen, Simon. “What is Theory of Mind, and Is It Impaired in ASC.” Autism spectrum conditions: FAQs on Autism, Asperger Syndrome, and Atypical Autism answered by International Experts, 2011: 136-138.
  • Baron-Cohen, Simon, Alan M. Leslie, and Uta Frith. “Does the Autistic Child Have a “Theory of Mind”?.” Cognition, 21.1, 1985: 37-46.
  • Gewin, Virginia. “Eye-Tracking Brings Focus to ‘Theory of Mind.’” Spectrum News, 29 Jul. 2009.
  • Soraya, Lynn. “Empathy, Mindblindness, and Theory of Mind.” Asperger’s Diary, Psychology Today, 20 May 2008.
  • Tager-Flusberg, Helen. “False-Belief Tasks Are Distinct From Theory of Mind.” Spectrum News, 15 Mar. 2011.
  • Thomson, Brittany M. “Theory of Mind: Understanding Others in a Social World.” Socioemotional Success, Psychology Today, 3 Jul. 2017.
  • Wellman, Henry M., David Cross, and Julanne Watson. “Meta‐Analysis of Theory‐of‐Mind Development: The Truth About False Belief.” Child Development, 72.3, 2001: 655-684. https:/s.semanticscholar.org/93da/6bc7aaa52478bed7852594d1a2237a2be544