Strategic deception as a marker of Theory of Mind development during early to middle childhood: A microgenetic approach



Although frowned upon within interpersonal interactions, deception is actually a normative behavior across the lifespan. A less sophisticated version of the ability to deceive can be first noticed in children as young as 3 years old. From there, it undergoes a fast and intensive
progress, with significant improvement during middle childhood, followed by a peak in adolescence and a slow decrease during adulthood.

However, there is a developmental paradox of deceptive behavior: while at younger ages, proficiency in deceptive behavior correlates with better socio-cognitive development (e.g. theory of mind, executive functioning), an overreliance on such behaviors in adolescence and later on is associated with negative socio-cognitive outcomes (e.g. symptomatic for malingering or antisocial personality disorders). Despite this, very little is known about the developmental shift between the normative aspect of deception and the problematic one, with significant changes hypothesized to take place during middle childhood. Our focus is on antisocial lies, defined as untruthful communications driven by self-interest, intended to harm others or to avoid punishment, as they are the first to emerge and the ones with the highest importance as markers of problematic behavior later on, highlighting the fundamental and societal significance of analyzing their early development.

Our focus is on antisocial lies, defined as untruthful communications driven by self-
interest, intended to harm others or to avoid punishment, as they are the first to emerge and theones with the highest importance as markers of problematic behavior later on, highlighting the fundamental and societal significance of analyzing their early development.


The general aim of the project is to enhance our limited understanding of the developmental interplay between strategic deception skills, executive functions, and Theory of Mind processes during early and middle childhood. Thus, the studies will specifically aim to:

 Evaluate and modify (using a microgenetic training design) preschoolers’ ability to strategically deceive an adult in a deceptive hide and seek game (Study 1).

 Evaluate and modify (using a microgenetic training design) young children’s (8-12 years) ability to use second-order lies to deceive an opponent in a deceptive hide and seek game (Study 2- S2).

 Evaluate (using an accelerated longitudinal design) young children’s (8-12 years) ability to strategically deceive in a resistance to temptation paradigm (Study 3).

  Assess the cognitive (EF) and socio-cognitive (ToM) correlates of this deceptive behavior, while controlling for individual differences in intelligence and parental practices (Studies 1, 2, 3).


Our project will bring significant conceptual, methodological and empirical advancements to the study of strategic deception in children.

● It integrates and relates for the first time socio-cognitive and emotional correlates (ToM, EF, internalizing/externalizing symptoms), within microgenetic (repeated bursts of measurement during short periods of time designed to generate qualitative changes) or longitudinal accelerated (various age groups of children evaluated several times) designs. This can offer unprecedented insight into the intricate mechanisms and individual differences subserving deceptive behavior.

 The project opens up new prevention and intervention avenues, by showing that simply exposing children to repetitive competitive scenarios can allow them to spontaneously discover and practice deceptive behavior.

  By offering opportunities to transform competition in a prosocial action (sharing the prize – thus generating a hypothetical cooperative scenario) we can investigate what sociocognitive ingredients are needed in order to expand the individualistic benefits of deceptive behavior.

  By intersecting individual differences in strategic deception competences with individual differences supporting altruistic behavior, we can identify very early on the children and the contextual factors (e.g. parental practices) most likely to generate altruistic vs. selfish behavior.

 This opens up new territories for individualized prevention and intervention strategies, which have so far only focused on the reducing the undesirable behaviors (strategic deception) without taking into account the level of competence in producing this behavior.

 Therefore, a more individually tailored intervention based on the level of sociocognitive competence of the child could:

1) foster their sensitivity to the competitive/cooperative nature of the context, and 
2) help them select the most advantageous strategy which would not only benefit the individual, but the group as well.

Our project lays the foundation for such personalized endeavors by identifying the key individual and contextual factors that underlie both strategic deception and prosocial behaviors in a unitary, microgenetic design.

Summary of Results

The present research project aimed to extend the empirical knowledge on the interaction between deceptive behaviour, executive functioning (EF) and Theory of Mind (ToM) among pre-schoolers and school-age children. This was completed by meeting the following specific objectives:

– To assess and modify pre-schoolers’ ability to mislead an adult through a 10-day training program (Study 1).

– To assess and modify the ability of school-age children (8-10 years) to switch between false and true information to mislead an opponent (Study 2).

– To assess school-aged children’s (9-11 years) ability to cheat and conceal this type of information within the temptation resistance paradigm (Study 3).

– To assess the cognitive (EF) and socio-cognitive (ToM) correlates of deceitful behaviour, by taking into account individual differences related to parental practices and other contextual factors (i.e., bilingualism or socio-economic status).

Results from previous studies have shown that children’s ability to mislead an interlocutor in preschool and school-age children is a normative aspect of this socio-developmental stage. This has been demonstrated by associating children’s deceitful behaviour with cognitive sophistication; those with increased deceptive skills also perform better on tasks measuring working memory, assuming others’ perspectives, or speaking multiple languages.

As a result of this project, 9 scientific articles have been published in leading journals such as Acta Psychologica and Child Abuse Review, as well as a book chapter in the prestigious developmental psychology collective volume The Wiley-Blackwell Handbook of Childhood Social Development, 3rd Edition, Wiley-Blackwell, UK.

In order to disseminate the present results, the members of the project team have participated throughout the 3 years period in numerous national and international scientific events, aimed for both the scientific community and for legal practitioners (expert psychologists, prosecutors). 

Among the most important scientific events where the project team presented their results were: The Society of Research in Child Development Biennial Meeting 2021, The Annual Conference of the European Association of Psychology and Law 2021, British Psychology Society – Developmental Psychology Section Annual Conference 2021, The 26th Biennial Meeting of the International Society for the Study of Behavioural Development (ISSBD) 2022, The 45th Conference of the International Group for the Psychology of Mathematics Education 2022, the International Investigative Interviewing Research Group (iIIRG) Conference 2022 and the 17th Conference of the Swiss Psychological Society 2022.