Upsetting memories and the images that derive from them have a powerful effect upon an individual’s mood state. Although mental imagery may have several different functions, some researchers believe that one function of mental imagery is a type of mental representation that serves to represent information about an individual’s goals – a kind of language of goals relating either to the future (e.g., with social anxiety) or to the processing of past events (e.g., as in posttraumatic stress). Mental imagery is also linked directly to emotion that can both maintain dysfunctional psychological states and thus act as a defense against goal change; conversely the generation of positive imagery can play a critical role in actively resolving distressing emotional states that lead to the formation of new more adaptive goals.