Theory of Mind: Four-year-revolution revisited

The standard picture of Theory of Mind development is this: Children begin to explicitly ascribe beliefs and other propositional attitudes to themselves and others around age four. Therefore, this has been considered as the age at which a fully-fledged Theory of Mind (ToM) is acquired. This picture is caused by numerous studies consistently showing that children master verbal false belief (FB) tasks reliably from age four on, while younger children fail to do so. The standard picture, though, has been attacked by two sorts of critique. On the one hand, studies using implicit measures show early competences in children much younger than four years of age, leading to an underestimation claim. Given children’s newly discovered implicit competences the standard picture seems to underestimate children’s real competence. On the other hand, studies on the scope of the explicit competence acquired at age four reveal limitations. This challenges the assumption that this competence is fully-fledged and therefore, raises the claim, that the standard picture may overestimate children’s real competence. This kind of critique has been called the overestimation claim. This dissertation focusses on the latter claim. This claim is borne by studies using two different kinds of tasks, tasks involving aspectuality understanding and tasks on true belief (TB) ascription. For both kinds of tasks, several studies have shown that only children much older than four years of age are able to pass them. Such findings cast doubt on the standard picture of ToM development, especially on the unity of the explicit competence. They bring into discussion the possibility that the competence children classically show around age four is limited or even based on the usage of simpler strategies rather than proper belief reasoning. In three studies, I investigate the validity of such findings of incompetence. For both, aspectuality understanding and TB ascription, I contrast competence-based with performance-based explanations. According to competence-based accounts children’s failure in aspectuality and TB tasks reflect a lack of competence. According to performance-based accounts, however, children’s failure is caused by performance problems and the standard picture of ToM development is true. Study 1, following a study by Rakoczy et al. (Rakoczy, Bergfeld, Schwarz, & Fizke, 2015), investigates 4- to 6-year-olds performance on a newly designed aspectuality task with reduced extraneous task demands. Study 1 shows that once aspectuality tasks are suitably modified children are able to solve them as soon as they master classical ToM tasks. The results of Study 1 therefore support a performance-based explanation of children’s former failure. Study 2 investigates TB competences of children older than four years of age. Experiment 1 in this study replicates and even extends findings of incompetence. However, Experiment 2 shows that once the procedure’s superficial qualities are changed, children are able to attribute TBs. This again, clearly speaks in favour of a performance-based explanation of children’s incompetence in former studies. Study 3 presents and empirically underpins a performance-based framework for the initial problem’s emergence. Taken together, these three studies suggest that previous findings of limitations of children’s explicit ToM constitute false negatives and that the classical picture of ToM development is justified