Perloff identified four factors as the reasons those individuals with strong attitudes towards a particular issue, as well as high involvement, might perceive hostile media bias: "selective recall", which causes partisans to focus more on contradictory information; "selective categorization", in which partisans categorize more content as unfair to their position than fair; "different standards", in which partisans classify more of the content that reflects positively on their position as accurate, and information that reflects negatively as inaccurate; and "prior beliefs about media bias", in which partisans judge media content unfairly based on a generalized negative set of beliefs about the media in general.