Abstract: Social media has changed the amount of information we have access to and the type of information we see. For example, individuals often publicly debate topics important to them on social media, and while one individual might be convinced by what a social media user has to say, another individual might be left unpersuaded. We are interested in what makes an ‘everyday’ argument like those found on social media persuasive to one person but not another. In two experiments, participants rated their beliefs about various political claims (e.g., ‘abortion should be legal’) and evaluated the quality of ‘good’ and ‘bad’ arguments about these claims. These ‘everyday’ arguments were designed to be like those seen on social media, with good and bad arguments manipulated to have either strong or weak evidence supporting their conclusions respectively. We find that participants consistently rated good arguments as better than bad arguments, but their argument quality ratings were also strongly correlated with their beliefs. Participants on average perceived arguments as being of better quality if it was also in line with their prior beliefs, with this overall effect of belief being around 3 times larger than the effect of argument quality itself. This finding was robust even when we controlled for potential order effects and demand characteristics; participants used their beliefs to assess the quality of the arguments despite being told explicitly not to, which they did irrespective of whether they saw the arguments before or after they rated their beliefs about the political claims. Our findings highlight that the same information can be perceived differently depending on a person’s prior beliefs.