18 Mar, 2026
A recent study published in Cognitive Development has provided new insights into how early children begin to recognize and engage in deceptive behaviour, suggesting that the foundations of deception emerge far earlier than previously assumed.1 Conducted by researchers from the University of Bristol and collaborating institutions, the study indicates that nearly 25% of infants demonstrate some awareness of deception by around 10 months of age, increasing to approximately 50% by 17 months. By the age of three years, children not only engage in deception more frequently but also display increasing sophistication and creativity in their deceptive behaviours.1
Traditionally, deception has been considered a complex cognitive skill requiring advanced language abilities and theory of mind. However, by drawing comparisons with deceptive behaviours observed in animals such as primates and birds, researchers identified early, non-verbal forms of deception in human infants.2 This broader framework allowed the identification of rudimentary deceptive behaviours much earlier in development than previously documented.
The study involved parental reports from over 750 children aged birth to 47 months across multiple countries, including the United Kingdom, United States, Australia, and Canada. Some parents observed early signs of deception recognition as young as 8 months of age, and once initiated, deceptive behaviours were reported to occur frequently, with about half of children engaging in such acts within a single day.1
Analysis revealed 16 distinct types of deception, with developmental progression noted across age groups. Around two years of age, children primarily engage in simple, action-based deception, such as ignoring instructions, concealing objects, or denying actions (e.g., shaking their head after eating a forbidden item).1 They may also perform restricted activities covertly or provide basic excuses to avoid tasks.
By three years, children demonstrate more advanced deceptive strategies that involve linguistic ability and an emerging understanding of others’ mental states, including exaggeration, fabrication, omission of information, and distraction techniques.3 These findings highlight that deception is a normative aspect of early cognitive and social development rather than a maladaptive behavior.
The study provides valuable implications for parents and educators by normalizing early deceptive behavior and offering age-specific expectations, thereby facilitating better communication and guidance strategies.1,3
References:
1- Hoicka E, et al. Early development of deception in infancy and toddlerhood. Cogn Dev. 2026;XX(X):XXX–XXX.
2- Byrne RW, Whiten A. Tactical deception in primates: the 1990 database. Primate Rep. 1990;27:1–101.
3- Talwar V, Lee K. Development of lying to conceal a transgression: children’s control of expressive behaviour during verbal deception. Int J Behav Dev. 2002;26(5):436–44.