New longitudinal study published in Development and psychopathology provide evidence that most children have low or declining levels of lying as they grow up, but that this generally does not cause serious problems in adulthood. However, the study also suggests that a small number of children who lie frequently or whose deception increases over time tend to develop symptoms of antisocial personality and are at higher risk of being convicted of a crime later in life.
Deception is a common human behavior that emerges from the preschool stage. Although most people have the cognitive ability to lie, research shows that most adults rarely do so. The overall rate of lying tends to decrease with age. However, a small portion of the population lie frequently and can develop problematic habits.
Past research has often viewed lying as a static trait or measured it at a single point in time. The transactional model of lie development provides another perspective. This framework conceptualizes truth and dishonesty as dynamic behaviors that change throughout a person’s life. According to this model, children’s tendency to lie is shaped by the continuous interaction between mental development, social environment, and individual personality traits.
Much of the existing research on childhood deception relies on short-term laboratory experiments. These experiments often place children in artificial situations in which they either lie for a reward or hide their misdeeds. Although these studies reveal how children acquire the mental skills necessary to lie, they do not capture how deception unfolds over many years in real-world settings.
To address this gap, researchers wanted to track lying patterns, or trajectories, from childhood to adolescence. They sought to determine whether different groups of children follow different paths of dishonesty with age.
“We know that the ability to lie emerges in young children through the development of cognitive abilities (theory of mind, executive function),” said Victoria Talwar, director of the Daniel Monica Gold Center for Early Childhood Development at McGill University’s School of Education.
Theory of mind refers to the ability to understand that others have different thoughts and beliefs than one’s own, while executive function includes mental skills such as self-control and working memory.
“But we didn’t know how these trajectories would develop,” Talwar said. “We had no association between childhood and adulthood. This data allowed us to examine how individuals’ lying behavior changes or remains stable from childhood to early adulthood.”
To answer these questions, scientists analyzed data from a Quebec longitudinal study of kindergarteners. The sample included 3,017 French-speaking children living in Quebec, Canada. This group consisted of 47.2% girls and 52.8% boys who were approximately 6 years old at the start of the study. Participants included a representative group of 2,000 children and a specialized group of 1,017 children who scored at the top level for disruptive behavior in kindergarten.
Researchers followed participants for 16 years. Parents and teachers served as observers and reported on children’s lying behavior at multiple points in time between the ages of 6 and 19. Adults rated the frequency of their children’s lies using a simple 3-point scale. They selected either “Not applicable,” “Sometimes,” or “Often.”
Parents also reported their child’s aggressive behavior at age 6 and again at age 19. They assessed items such as fighting, biting, bullying, and destruction of property. Teachers rated impulsivity in 12-year-old children. This included assessing how often the child acted without thinking or screamed for attention.
Once participants reached 22 years of age, a trained assistant conducted a clinical interview based on standardized psychiatric guidelines. They evaluated young people for symptoms of antisocial personality disorder. This mental health condition involves a long-term pattern of manipulating, exploiting, or violating the rights of others and is often accompanied by a lack of remorse. The researchers also collected official juvenile and adult court records for the participants. These records included convictions between ages 13 and 25.
The scientists then used statistical grouping techniques to identify different pathways of lying behavior based on parent and teacher reports. Because parents and teachers were observing children in very different settings, the researchers analyzed the two sets of reports separately.
Teacher reports revealed three distinct pathways of lying behavior. The majority of the sample, 73 percent of the children, fell into the “low lie” group. These children lied at very low rates at age 7, and this behavior decreased to almost zero by age 15. The second group, comprising 22% of the sample, followed the path of “increased lying.” Their deception started higher than the first group and slowly rose to occasional rates by the mid-teens. A third group, based on teacher reports, showed a pattern of “decreasing lying.” This group made up 5% of the sample and initially had the highest rate of lying, but by the age of 15 this had dropped to almost zero.
Parent reports also revealed three unique behavioral pathways. The largest group, 58 percent of children, showed a pattern of “occasional lying.” According to their parents, these children lied at a stable and moderate rate from age 6 to age 19. Another 30% followed a “low-lying” trajectory. These children started out with low deception rates that gradually dropped to near zero. The final 12 percent showed a “curvilinear” path. These children lied moderately at age 6 and experienced a peak in deception around age 8 to 10. After this peak, their lying rates declined sharply toward zero by late adolescence.
Talwar reviewed the findings and noted that the results were in line with researchers’ expectations. “In many ways, this confirmed what we thought, but we didn’t have the evidence to know for sure,” she told PsyPost.
“Most children don’t lie much, but as they get older they tend to lie less,” Talwar explained. “We found that the majority lied infrequently or only occasionally, and that their trajectory was stable or decreasing. Frequent lying was not the norm, and only a small minority showed increasing levels over time or persistently high levels. So while lying is typically common in childhood, it is not a sign of a major problem for most children.”
The authors found that early problem behavior predicted which path of deception a child would follow. Children who showed higher levels of aggression at age 6 were more likely to end up in a lying group or in a group that increased their rate of lying. Similarly, children rated as highly impulsive by their teachers at age 12 were more likely to be in the deceptive group compared to the less likely lie group.
“The small number of children who had aggression in childhood or high impulsivity in adolescence were more likely to follow a trajectory of higher levels of lying,” Talwar said. “This means that problematic lying is often part of a broader pattern of behavioral problems, rather than an isolated problem.”
When researchers looked at outcomes in adults, they found that long-term patterns of lying were associated with future problems. According to teacher reports, children in the group who told more lies showed more symptoms of antisocial personality disorder in early adulthood than children in the group who told fewer lies. Their records also included convictions for more violent and nonviolent crimes.
Children in the stable and occasional lying group had the highest rates of adult aggression, according to parent report. This group also had the highest rates of antisocial personality symptoms and criminal convictions. In contrast, children in the low-lying or reduced-lying groups had the fewest adult criminal histories and psychiatric symptoms.
“For those who continued to lie or lie a lot, this was predictive of later problems: increased aggression, symptoms of antisocial personality disorder, and higher rates of criminal behavior (though still low overall),” Talwar said. “Lying that is too persistent and conspicuous can be an early warning sign of later adjustment problems.”
The findings of this study suggest that persistent lying, when observed in parallel with other behavioral problems, provides evidence of a trajectory toward maladaptive outcomes in adults. “But for parents, it’s important to remember that while most children lie occasionally and outgrow the lies as they grow up, persistent and escalating lies, especially in tandem with behavioral problems, can signal an increased risk of later antisocial outcomes and require early support,” Talwar added.
There are some potential misconceptions and limitations to consider. This study uses a simple three-point scale to measure lying down. This broad classification fails to capture the nuanced motivations behind lies. They cannot distinguish between malicious lies told for personal gain and prosocial lies told to protect the feelings of a friend.
Additionally, this measurement tool does not capture the actual frequency of all lies told by participants. Instead, parents and teachers can only report lies they actually discover. Adults are notoriously bad at detecting children’s lies. For this reason, this study primarily measures socially visible cheating, rather than the absolute number of lies told by children.
Talwar pointed out this limitation in the methodology. “These are lies reported by parents and teachers, not self-reports or behavioral norms (which are difficult to do at an early age),” she says. “So there could be lies that parents and teachers didn’t catch and report.”
This sample also included a disproportionately large number of children who exhibited disruptive behavior in kindergarten. This overrepresentation may have made it easier to detect associations between early problem behaviors and later criminal outcomes. The researchers also did not consider other external factors. Variables such as family socio-economic status and untreated internalizing problems such as anxiety can influence both childhood behavior and adult legal troubles.
Future studies should attempt to measure lying status using more accurate and continuous scales. Scientists could also benefit by investigating the specific types of lies that children tell across different stages of development. Tracking individuals into adulthood could help reveal how childhood deceptions affect long-term career success and personal relationships.
“This shows that not all lies are the same,” Talwar said. “In the future, we hope to identify different subtypes of chronic lying and their different causes and consequences. This will help detect problematic trajectories early and design more effective interventions for early support.”
The study, “Longitudinal Perspective: Lying Trajectories from Ages 6 to 19,” was authored by Victoria Talwar, Angela M. Crossman, Christy Robinson, Marie-Claude Geoffroy, Silvana Côté, Richard Ernest Tremblay, and Frank Vitaro.
