Matching mind to world and vice versa: Functional dissociations between belief and desire mental state processing.

With the aim of understanding how different mental or intentional states are processed in the brain, the present functional magnetic resonance imaging (fMRI) study examined the brain correlates during the ascription of belief intentional states relative to desire intentional states as well as the effect of incongruent relative to congruent intentional states. To this end, sentences containing scenarios were presented to participants and their task was to make judgments concerning the ascription of intentional states based on this information. Belief ascriptions, relative to desire ascriptions, were accompanied by activations in lateral prefrontal structures that include areas known to be involved in relational and conceptual reasoning. Desire ascriptions, in contrast, were accompanied by activations in regions of the medial prefrontal cortex, superior temporal gyri and hippocampal formation, all of which are known for their involvement in self-referential, autobiographical and episodic memory-relevant processes. In addition, the ascription of intentional states that were incongruent with reality (false beliefs and unfulfilled desires) was compared to the ascription of intentional states that were congruent to reality (true belief and fulfilled desires). While no brain region was selectively activated during the processing of unfulfilled desires, the processing of false beliefs was associated with stronger activations in the dorsal medial prefrontal cortex, an area that has been previously linked to the process of decoupling in false belief attribution. These findings provide new insights into more fine-grained aspects of mental state reasoning.