Bias has been a factor of news since time immemorial. A wide range of studies have shown that for radio, television, print news, and online news, the production, dissemination and consumptions stages of the news cycle are rife with opportunities for its influence and effect. Three recent experiments demonstrate that the perception of bias in news articles online is impacted by their visual presentation, and that it can be predicatively impacted. This presentation will explore this phenomenon, highlighting the lack of underlying theory explaining judgements of bias. To begin, bias as a construct is examined demonstrating the need for a classification of biases including definitions of the term. Due to the lack of underlying theory the overarching domain of credibility is explored. Bias is a core dimension of credibility, especially when judging news online. Credibility is often defined in terms of believability and or as a multi-dimensional construct. Ten cognitive models, theories, frameworks and schematics which explain how users judge the credibility of information online are briefly examined. Most of these highlight the importance of the visual presentation of the information. Many of them are built on underlying theory provided by the Elaboration Likelihood Model (ELM) and the Heuristic Systematic Information Processing Model (HSM), two of the Dual Process Models of Persuasion. In general, these maintain that humans process information via two routes, a conscious route and a preconscious route. The ELM and HSM are built on foundational work in psychology such as the Controlled and Automatic Human Information Processes (C&AHIP). The richness and lineage of theory for credibility throws into stark contrast the lack of theoretical underpinnings for judgements of bias.