The Effects of Opinion Labels on News Source Credibility Online

This dissertation seeks to answer the pressing question of whether labeling opinionated content online as opinion affects readers’ perceived credibility of news sources and trust in the news media. This research was motivated by the many search engines and social media sites that do not label opinionated content as such on their platforms. To answer this question, two studies explore the effects of ‘opinion labels’ on news previews (known as ‘story cards’) on readers’ perceived credibility. Story cards are employed because news consumers often interact with them instead of news websites. In study one, a 3 (news source) x 2 (headline opinion polarity) x 2 (presence of opinion labels) between-subjects design investigated the effects of opinion labels on the perceived credibility of news sources when participants (N = 389) were presented a feed containing biased and unbiased content from one news source. In study two, a mixed design with three levels (prominence of opinion labels) investigated the effects of opinion labels on readers’ perceived credibility of news sources when participants (N = 275) were presented a feed containing biased and unbiased content from multiple news sources. Study one found that labeling opinionated content as opinion significantly increased the perceived credibility of a news source (p < .01). Additionally, opinion labels significantly changed credibility perceptions even among political affiliates viewing oppositional content. Findings from study one suggest opinion labels increase perceived credibility because the labels increase perceived opinion segmentation – the distinctions between news and opinion and between author and source. Previous research indicated that heuristic cues need to be of sufficient visual prominence to affect perceived credibility. However, study two found that the prominence of the labels did not have an effect in a multiple source environment. Findings from study two therefore support the source blindness effect over the prominence-interpretation theory. This dissertation deepened knowledge of heuristics and credibility theory by examining how and why heuristic cues, specifically opinion labels, affect readers’ perceived credibility of news sources. The findings have broad socio-political implications as they indicate that design choices such as labeling content can significantly impact credibility and media trust