Theory of Mind interacts with semantic comprehension in 14-month-old infants.

Forgács, B., Gervain, J., Parise, E., Csibra, G., Gergely, G., Baross, J., Király, I. (2019). Theory of Mind interacts with semantic comprehension in 14-month-old infants. Poster presented at the Budapest CEU Conference on Cognitive Development (BCCCD19), Budapest, Hungary. 


Infants employ sophisticated communicative and Theory-of-Mind (ToM) abilities well before they start to talk. In a previous study, using an object naming paradigm in a live puppet theater setting, 14-month-olds produced an N400 to semantic incongruity experienced by another person, who had a false belief about the identity of the named object (Forgács et al., in press). The current stud- ies further explored this phenomenon in three electrophysiological experiments, using the same paradigm. First, we replicated our initial finding: we induced a false belief in the adult observer by replacing an object with a second one without her knowledge, and then named it correctly from the perspective of the infant – which was incongruent with the false belief of the observer. Intriguingly, the replicated N400 effect was not accompanied by a later frontal negativity, as in the original study, but by an early frontal positivity. In the second study, we inverted the situation: the objects were always labeled incongruently from the perspective of infants, but sometimes congruently with the adult observer’s false belief. In the third study, we used the original paradigm, but we replaced the first object with another one of the same kind. The latter two follow up studies indicated no N400 effect, but an early frontal positivity. These results together argue against an initial, perception-based ToM, and suggest that language comprehension relies on ToM earlier than previously believed by allowing infants to track the understanding of communicative partners.