The ability to infer other people's mental states such as desires, emotions, intentions and beliefs is essential for successful social interactions, and it is usually referred to as theory of mind (ToM). In particular, the ability to detect and understand that people have beliefs about reality that may be false is considered an important hallmark of ToM. This experiment reports on the results of 18 participants who viewed photographic sequences of an actress performing actions as a consequence of true and false beliefs. Consistent with prior work, results from the passive viewing of stimuli depicting true belief indicated an increased response over frontal, central and parietal regions when compared with the amplitude for the false belief condition. These results show that (i) frontal activity is required for processing false belief tasks and (ii) parietal effects reported in previous studies to reflect specific cognitive process of monitoring others' beliefs can be elicited in the absence of an explicit instruction for mentalizing.