Recursion in language, theory-of-mind inference and arithmetic: aphasia and Alzheimer's disease

We found a variety of dissociations among the linguistic and non-linguistic operations tested. In the case of Hungarian speaking patients with a medium-serious AD, syntactic recursion is relatively unimpaired, as opposed to their limited ability to tackle theory-of-mind and arithmetical recursion. Conversely, we found limited syntactic recursion but normal theory-of-mind inferences and recursive arithmetical operations in Hungarian speaking agrammatic aphasics. We argue for a model that posits a module of recursive operations in the human mind that is shared by linguistic, theory-of-mind, and arithmetical performance.