What determines adults’ difficulties in mental states inference ?

An accumulating body of evidence shows that adults don’t perform flawlessly on Theory of Mind (ToM) tasks, and that the reason for this is linked to an executive component of ToM reasoning, namely the need to inhibit one’s own perspective. But recent neuropsychological studies have shown the influence of another executive component linked to the inhibition of salient distracting information in the environment. It is currently unknown whether adults show differential difficulties for the inference of different types of mental state. Developmental studies show that children find it easier to reason about emotion than desires and easier to reason about desires than beliefs. However, the executive components have usually not been matched across mental states. In this study, we examined adult’s ToM by contrasting the inference of different types of mental states (emotions, desires/intentions and beliefs) and orthogonally manipulating the type of executive demands (self-perspective inhibition and inhibition of salient distracting information in the environment). Results show that participants’ performance was not flawless (8 % errors on average) and that the errors evenly spread across the different mental states. Furthermore, errors were equivalent across types of executive demands (and even marginally higher in the inhibition of salient distracting information condition).