My fingers pick up the pen, but I don’t control them. What they do is nothing to do with me. (Mellors, 1970, p.13) DELUSIONS of alien control are symptoms associated with schizophrenia in which people misattribute self-generated actions to an external source (Schneider, 1959). The actions in question can be mundane, such as picking up a cup or combing one’s hair. Auditory hallucinations are common in schizophrenia, and normally consist of hearing speech or voices (Johnstone, 1991). Both delusions of alien control and auditory hallucinations are included as ‘first rank’ features in schizophrenia (Schneider, 1959). But what can such phenomena tell us about how we know that our own actions belong to us? How are we able to distinguish self-generated sensory events from those that arise externally? Here, I describe behavioural and brain-imaging experiments designed to investigate these questions.