To have a theory of mind (ToM) is to realise that others have minds like yours. Elementary as that sounds, it’s a question that has engaged philosophers, evolutionary psychologists, and researchers of schizophrenia and autism. Experts assumed that humans were the only species to have a ToM, but it has emerged that not only primates, but parrots, crows and even rats have recently shown the ability to grasp the ‘I know that you know that I know’ loop that underlies social relationships. A broken ToM can result from damage to specific brain regions and also informs research into the neurology of empathy.
