Imagine asking about last night's football game. A friend says ’It was a draw’. Another one shakes their head: ’No, it was 2:1 to the home team!’ You’d have a hard time deciding whom to believe. But if both statements came from the same person, you’d likely accept the second result, assuming your friend has just misremembered but then promptly corrected himself. This interpretation is based on the principle of psychological coherence: the notion that contradictory mental states are not likely to coexist within a single mind. In other words, your friend probably doesn’t disagree with himself (while he may very well disagree with other people or remember the same things differently over time). The intuitive sense of psychological coherence shapes how we interpret others’ actions and communication – and as the newest findings suggest, we already rely on it in the first year of our lives.
Ágnes Kovács (Central European University) and Olivier Mascaro (CNRS) investigated whether infants also apply a principle of psychological coherence. Fifteen-month-olds watched informants point to indicate the location of a hidden toy. When two different people each pointed to a different spot, infants were unsure where to look for the toy: they were equally likely to search in both locations. But when the same person pointed first to one location, then to another, infants reliably followed the second gesture — treating it as a correction rather than a contradiction. The pattern suggests infants assumed that one speaker would not convey a contradictory message — here, simultaneously claiming a toy is in two places at once.
The researchers also wanted to find out if infants would expect psychological coherence when it comes to actions. In a series of looking-time experiments, 9-month-olds watched two gloved hands interact on a table. The first hand grabbed some objects and arranged them in a straight line. When it reached for the last item, the second hand blocked it. Then it was revealed that the hands either belonged to two different people or the same individual. Infants were surprised when the two hands belonged to the same person and seemed to follow conflicting goals. The researchers interpreted this as evidence that infants find it implausible for a single agent to thwart their own goal.
These results suggest that the mechanisms of “theory of mind”—the ability to attribute mental states to others— rest on assumptions about the way multiple mental states are organized within a mind. They rely on intuitive assumptions of psychological coherence, which are not learned slowly over childhood, but may reflect a core, early-emerging component of human social cognition.
Original paper: Mascaro, O., Kovács, Á. M. (2026) Core Intuitions of Psychological Non-Contradiction: Infants Assume That Individual Agents Act and Communicate Coherently. Open Mind (2026) 10: 287–305.
