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When children lie they are simply reaching a developmental milestone

Dominika Osmolska Psy.D.'s picture

If your previously innocent, blundering toddler has morphed into a sneaky little liar, don’t sweat it. A new Canadian study links the ability to lie to an important developmental milestone. Lying is, it turns out, an integral part of healthy brain development.

The study, conducted at the Institute of Child Study at Toronto University, surveyed 1,200 children aged two to 17. The children's honesty was tested by telling them not to peek at a toy placed behind their backs while leaving the room. Their reactions were then monitored by video and the children were asked if they had turned around. Their responses were checked against the recording.

Only a fifth of 2-year-olds were able to lie. But by age 4, 90 percent were capable of lying. The rate peaked at age 12.

Dr. Kang Lee, director of the institute, said parents should not be afraid that their children are going to turn out pathological liars if they catch them in a lie. Although it is wise to instruct children that lying is not a good practice, which is part of shaping them into ethical individuals, parents should not be overly distraught by the presence of recurrent lying.

That’s because lying is an integral part of developing what psychologists call a “theory of mind.” Briefly, theory of mind is the ability to attribute mental states—beliefs, intents, desires, pretending, knowledge, etc.—to oneself and others and to understand that others have beliefs, desires and intentions that are different from one's own.

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The presumption that others have a mind is termed a theory of mind because each human being can only intuit the existence of his or her own mind through introspection, while no one has direct access to the mind of another. Having a theory of mind allows you to attribute thoughts, desires, and intentions to others, to predict or explain their actions, and to speculate about their intentions. If a person does not have a complete theory of mind it may be a sign of cognitive or developmental impairment. The inability to lie is a sign that a child’s theory of mind is not fully operational – that child, in other words, cannot imagine that another mind exists within its own frame of reference and which can thereby be deceived.

In fact, one of the hallmarks of autism spectrum disorders is just such an impairment in the ability to imagine another isolated mind with its own sense of reality and perceptual constraints. Individuals classified as having autism have severe difficulty assigning mental states to others, and they seem to lack theory of mind capabilities.

Researchers in the field of autism have been studying “false-belief” tasks (essentially, lying tasks) for years in order to help clarify the intricate developmental trajectory involved in theory of mind. A now classic false-belief experiment, referred to as the “Sally-Anne” task, involves a story about two characters, Sally and Anne. The child is shown two dolls, Sally and Anne, who have a basket and a box, respectively. Sally also has a marble, which she places in her basket, and then leaves to take a walk. While she is out of the room, Anne takes the marble from the basket, eventually putting it in the box. Sally returns, and the child is then asked where Sally will look for the marble. The child passes the task if she answers that Sally will look in the basket, where she put the marble; the child fails the task if she answers that Sally will look in the box, where the child knows the marble is hidden, even though Sally cannot know, since she did not see it hidden there. In order to pass the task, the child must be able to understand that another’s mental representation of the situation is different from their own, and the child must be able to predict behavior based on that understanding. The results of research using false-belief tasks have been fairly consistent: most normally-developing children are unable to pass the tasks until around age four.

Those statistics correlate nicely with the research findings at Toronto University.

A fascinating supplement to the research is that most children with Down’s syndrome, a pervasive developmental disability, are able to pass the test, while most children with autism cannot.

Theory of mind impairment is basically an impairment in the ability to see things from a perspective other than its own. Lying clearly demonstrates that ability.

In addition to autistic individuals, persons under the influence of alcohol and narcotics, sleep-deprived persons, and persons who are experiencing severe emotional or physical pain, as well as schizophrenics, demonstrate varying levels of theory of mind impairments.